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loose nut
01-10-2014, 01:45 PM
Anyone have any experience with these.

After a little research it looks like the electric whole house ones require a very large energy demand when on, some quote a 300 amp house hold service requirement. Still cheaper then running one all the time but installation costs would be out off the question.

Gas heaters look better, installation problems too, so we are getting an estimate.

Has anyone any experience with these. What kind of problems have you had, like limited water availability, high gas usage etc.???? Maybe you think they are great. Would like to know before I get in to deep. Thanks.

Mike Hunter
01-10-2014, 02:03 PM
I installed one in our addition, its a Bosch... I should have done it years ago. LP model, uses SCH 40 PVC pipe for exhaust, 10 yr warrantee, the thing is awesome.

I have two teenage kids, 20-30 min showers are not uncommon, the thing keeps heating water until you run out of propane or run out of water. 250 gal propane tank lasts about a year.

The model we have, has an electro-piezo ignition system, so it activated by the flow of water thru the heater, meaning with power outages we still have hot water.

The only issues is that it takes a little time for the water to warm up.

Seastar
01-10-2014, 02:24 PM
Six years ago I built a seasonal cabin for my kids on my remote isolated Northern Minnesota property.
The only power we have is a 500 gallon tank of propane that runs the refrigerator, the stove, the heat and an 8 kW generator for lights, TV and the well pump.
I also installed a propane fired tankless hot water heater. A Japanese Takagi.
It worked fine until this year when it refused to light unless two faucets were open to make maximum water flow.
There is a paddle wheel inside that detects water flow and lights the unit.
I had to rig a hose to add vinegar to the unit to dissolve the lime deposits and free up the paddle wheel sensor. By the end of the season it had quit again.
Next spring I am going to use a solution of CLR to clean out the gunk before I turn on the well.
When I bought the heater it was the best in the market and one of the few. It cost $2500.
Today there are several brands that operate on natural gas or propane.
The electric tankless units do require very large currents and usually mean rewiring the house.
Be careful what you buy.
Bill

jlevie
01-10-2014, 02:41 PM
I have friends who have gas fired tankless water heaters and they are generally happy with them. But all have found that professional servicing once a year is required.

daryl bane
01-10-2014, 02:44 PM
We put in a nat.gas Bosch a number of years ago and the only issue was that it required much larger gas inlet line than a regular heater. This might have changed now with current models.

rickhann
01-10-2014, 03:10 PM
My wife and I live on Cape Cod. We have had a Rinnai Tankless Heater for 5 years. It is a natural gas model. There are just the two of us and we have been very happy with it. We set it at 115 deg F and the water is plenty hot for a shower and or a bath. Now for the negatives I have recently discovered. The vent leaves the house approximately 2 feet above the ground at about the same height as the High Efficiency Furnace vent. This is an area where snow drifts next to the house and you have to keep the vents clear or they both will shut off if snow blocks the vents. The tankless heater does require a sufficient supply of gas or it will groan and moan loudly and or shut itself off when it is asked to produce hot water at full capacity. Cutting down the flow of hot water needed will stop the noise. This only happens when the temperatures are cold as we have recently discovered. Like I say, we are happy with it, but if you are planning to install one make sure you have sufficient gas to run it. There are several FAQ sites about these heaters that will answer any questions you might have.

Rick

Tony
01-10-2014, 03:15 PM
+1 on the yearly maintenance. They are efficient but you must keep them clean.
My only complaint is that you (I) don't get hot water as fast. Maybe its just my plumbing, but we have to
leave the faucet run probably a good 20 seconds before we get hot water.

20 seconds maybe doesn't sound like a lot, but it gets tiresome. Other than that, no complaints.

I'd suggest installing one 25-50% larger (BTU rating) than the handbooks suggest.

Mike Burch
01-10-2014, 03:17 PM
I hate the things!
They heat the water through a temperature range, not to a fixed temperature. The output temperature therefore depends on a) the input water temperature, and b) the water flow through the heater. So for the same flow the hot water will be cooler in winter than in summer; and if some one tries to wash the dishes while you're under the shower you will have a sense of humour failure. No doubt many people can cope with that, but it drove me nuts.
Years ago I used to have an electric instant water heater for the shower, and it was hopeless.

Sparky_NY
01-10-2014, 03:36 PM
I hate the things!
They heat the water through a temperature range, not to a fixed temperature. The output temperature therefore depends on a) the input water temperature, and b) the water flow through the heater. So for the same flow the hot water will be cooler in winter than in summer; and if some one tries to wash the dishes while you're under the shower you will have a sense of humour failure. No doubt many people can cope with that, but it drove me nuts.
Years ago I used to have an electric instant water heater for the shower, and it was hopeless.

The symptoms you mention are typical of a improper installation (gas piping too small/low pressure) or a unit that was sized too small for the house. They hold temperature very well due to a modulated gas valve with a typical range of 30-130000 btu depending on water flow and inlet temperature. I have installed many and also repaired quite a few with symptoms like you mention. It typically happens when someone does a DIY install and simply connects to the existing gas line from the old tank type heater (1/2 inch being common)

Sparky_NY
01-10-2014, 03:45 PM
Everything stated thus far is pretty accurate. They work very well. As for maintenance, the main thing is a inlet screen filter that has to be cleaned. If you are on well water or other that is very hard then buildups can become a problem. I installed quite a few for people and they worked well with no call backs. Many years back, I did my house first, with a Bosch unit.

For the original poster... They cost quite a bit fully installed because there is quite a bit of work to do it correctly. Gas supply is CRITICAL to proper operation. For example, Bosch devotes about half of their installation manual to the gas supply subject. The typical units high flame is 130000 btu or a much as 200000btu. If the gas supply is insufficient due to undersized piping, it cripples the units performance. They just do not tolerate pressure drop when the flame cranks up high.

DFMiller
01-10-2014, 04:04 PM
We have had a Rinnai for about 6 years. We love it. The plumber who installed it said he liked it better than the Bosch.
It just works. What more could you ask for.
Dave

rws
01-10-2014, 04:42 PM
We install them in the buildings at work. LEED crap you know. Do they work better than a tank heater, no. re they mor efficient? Don't know. Would I buy one? Not a chance in hell. There is nothing wrong with the tried and true tank water heater. They don't require a yearly maintenance, they last for at least 10-15 years. You can install a simple timer if you want to cut power over night and/or during the day. No fuss no muss. Not a chance in hell..........

jeremy13
01-10-2014, 05:07 PM
We install them all the time only pre-determining factor is water quality. The harder the water the faster you will need the heater flushed out. I have some that are going on 11 years old never a call back. And some in 3 years. If you have a water softener that's a plus to life of the unit. Now as far as gas pipe size yes you will need bigger lines possibility. Some units go as big as 199,000btu. The new Navien heaters do not require bigger gas lines. They will run on the existing lines you have. There is something similar to a turbo fan in the gas system that pulls the required gas it needs.

jeremy13
01-10-2014, 05:46 PM
I forgot to add we see a large drop in gas usage when someone changes out a tank water heater to a propane tankless heater, over 200gal a year drop.

loose nut
01-10-2014, 07:02 PM
I should have added in the first post that I have a crawl space not a basement and I can't put a regular gas water heater down in it. Electrical costs here are ridiculous, that why I would like to go to gas.

1-800miner
01-10-2014, 08:41 PM
My gas unit has been working for fifteen years. On occasion we can't shower and dish wash at the same time.More noticeable in the winter.
I saw a drop in the propane bill right away.
I installed tees on the cold and hot lines. Every few years I tap into the tees with a pump and circulate vinegar water for a few hours. Works like a champ.

I had to wait a while for hot water to reach the bathroom.(about twenty five feet from the heater).
I took out the one inch hot water supply line to the bath and replaced it with half inch.
Water gets there much faster.

chipmaker4130
01-10-2014, 09:43 PM
I suppose the new stuff is probably better, but gas instant units were more common in Austria in the mid-seventies than tanks, and in my experience they didn't really get the water HOT. The inlet temps were, of course fairly cold, but even with a light load and full hot selected it wasn't what I'd call a hot shower.

Don Young
01-10-2014, 10:24 PM
Just noticed a news item about cold weather plumbing problems and the plumber was thawing out a tankless gas unit that was installed outdoors. That might be a consideration since they require combustion air and there is little or no stored heat.

gizmo2
01-11-2014, 09:15 AM
We've had a Rinnai up and chugging about 6-7 years now, downstream of a water softener so we haven't had any scale build up problems yet. Our problem is Miller moths; they get into the squirrel cage and when it gets unbalanced the unit starts growling. Have to take the blower out a couple times every summer and muck it out. Otherwise it's been a treat.

Rosco-P
01-11-2014, 09:27 AM
If you adhere to the unit's requirements, there are little or no problems. If you insist on doing it your own way, your mileage may vary. Yes, they may need to be de-scaled, they make a flush kit for that. Yes, they need an adequately sized gas supply, 1/2 or 3/4". But is black iron pipe really that expensive? They need access to exterior combustion air and exhaust within 6(?) feet. Use your existing chimney? No. Does keeping 30, 40, 50 gallons of water hot while you sleep waste money and fuel? Absolutely. Most complaints trace back to poor installation choices.

sch
01-11-2014, 10:42 AM
Gas supply never crossed my mind til the temps here went down to 11F last week, noted that the stove burner flames were smaller than usual and one of the three furnaces had an ignition failure
trouble light, one didn't blow hot air for several hours and the pilot on the gas tank water heater went out. All of this resolved as the air temp went up over the next 6 hours. If you have NG, be
aware that the NG meter attached to your house has a limit on how much gas it can proviede. In my area meters with a white face have lower limits than meters with a red face. Your utility "may"
be willing to tell you what your meter can supply, mine said "ask your contractor" when I called to ask before an NG generator install last summer. Before last week I figured the generator would
be no sweat in the winter when power needed to run a furnace is minor compared to AC, but now I realize a gas supply limitation in a winter disaster might constrict the generator significantly.
Fortunately, in my areas these are much rarer than tornado/hurricane disasters from a power loss POV. The gen full bore draws about 360 CF NG/hour.

As to tankless maintenance, go to utube and search on maintenance of tankless water heaters for some useful info. A decent sized unit has to have a large gas supply, a vent to the outdoors and
for maintenance ease of access is a good idea.

Stern
01-11-2014, 11:25 AM
Contemplated getting one years ago when they first came out, but fortunately I was doing work in a B&B place at the time where a large new one was installed (This place was for rich people from out of town). Well, after 3 years of dicking with it they never did get it to work the way they wanted it, and after learning a lot about them I decided to stick with my good old gas fired tank (which also works without power, which is good as I at least had hot water the 6 days at Xmass we had no power).
From what I learned about the tank-less heaters (electric or gas) is they work on raising the incoming water temp XX deg .... thats it. Now thats ok I guess for places that are warmer, but here our incoming is cold .... sometimes in winter its commonly around 3 deg C. Big thing is you need a unit that will produce the XX deg temp differential you want, and that is based on its bower (size, BTU rating, etc).

Concept is fine, but unfortunately the end results dont fit most peoples idea of what "hot water" to them means.

firbikrhd1
01-11-2014, 11:26 AM
While I ahve no personal experience with them I did some research a while back about getting a gas tankless heater. What I came up with is that recovering the cost of a tankless unit and it's installation would take years, probably the life of the unit. That was a while back but I eventually opted for a high efficiency conventional gas water heater. My research was done several years go so costs may have changed.
Right now I am building a new house and it will incorporate a conventional gas hot water heater with recirculation pump. I plan to use the circulating hot water to heat my shop as well as supply hot water to the rest of the house.

michigan doug
01-11-2014, 11:50 AM
They are more "efficient", in that they have zero to trivial storage tank losses.

On the other hand, let's say your normal gas water heater is sited in the conditioned space of your house, like a central, first floor utility room. Where does the "waste" heat go? Yeah, it heats your house. So, in the fall, winter and spring, you're reducing the amount of heat the furnace has to supply.

If it's in an unheated garage, well, that doesn't help you so much.

I did a spreadsheet a few years ago and it was an uphill battle to recover the extra cost by true energy saved alone. And, they are fussier. If they are sized a bit too small, the supply line or hot water line too big or too small, to many things on at once, you won't get the consistent hot water you would with a tank model.

Don't forget, there are more efficient tank models out there too.

doug

DR
01-11-2014, 12:19 PM
Tank-less natural gas unit purchased from Amazon about 5 years ago. No maintenance so far.

When we had a new gas furnace conversion (under permit) from oil I had the installer leave a stub line so I could install the unit with my son's advice, he's a contractor. Simple installation, hook to gas line and water, plug into 120V outlet.

Substantial saving over former electric water heater. Plus, both showers, clothes washer, dish washer all at the same time.

The one thing that drives me crazy is I can't convince my wife to use only cold when she's just quickly wetting a sponge to wipe the counters. When I'm in the basement the thing is constantly going on/off in short bursts because of this. The time required to get hot at the kitchen faucet is another annoyance even though the unit is right below the kitchen sink.

A couple houses my son built they use an instant hot tank-less. They keep hot water circulating with a small pump in your in-house piping, so the piping is equivalent to a small storage tank. You do get almost instant hot in the farthest away faucet at an increase in cost of keeping the piping system heated and more complexity of the pump, etc..

RichR
01-11-2014, 12:25 PM
The time to recover the cost of a tankless heater is also a function of why you are installing it. If you need to install a water
heater because the existing one failed or you are dealing with new construction, the payback will be quicker. If a hot water
tank is going to cost you $300, you have to spend that regardless of which type you choose, so the payback would be based
on the price difference between the two types.

On a side note, if you can feel any warmth when touching the side of your hot water tank, one of those insulating wraps for
hot water heaters may provide a better return on your money.

Rosco-P
01-11-2014, 01:03 PM
Rheem 40g (low efficiency model) 6yr warranty water heater at HD $350 approx., Rheem high efficiency RTGH95 12 yr tankless $1300 approx. Using the energy saving calculator on the website (4 showers per day), payback period could be 6 to 7 years or less, not including any local utility, state or government rebate programs.

Sparky_NY
01-11-2014, 01:29 PM
Rheem 40g (low efficiency model) 6yr warranty water heater at HD $350 approx., Rheem high efficiency RTGH95 12 yr tankless $1300 approx. Using the energy saving calculator on the website (4 showers per day), payback period could be 6 to 7 years or less, not including any local utility, state or government rebate programs.

Rheem tankless heaters were not made by rheem but by a big tankless heater company Paloma. The mention of Home Depot reminds me of something, Bosch sold tankless heaters through home centers, THEN also had their Pro-Tankless series which was only sold through plumbing supplys. The two units looked near identical BUT the pro series had 20 year warranty compared to 10yrs for the home center models. The old "buyer beware" story. Also, $1300 for the rheem at home depot is no bargain, most big name tankless heaters sell for under $1000 to the pros.

All these posts never mentioned the problem of running out of hot water in a house with kids, big jacuzzi tubs or for other reasons. Nothing like getting ready for work and NO hot water for your shower!!!!!!!! Put a price on that !!!

Every spring, I used to wash the motorhome with the garden hose using hot water. The nozzle required a glove to hold onto BUT nothing cleans like hot water. I only did it for the initial spring cleaning but what a difference. Try that with a tank type heater!!

The last tankless I installed was for a 4 bath house with 6 kids, a perfect application if ever there was one.

Jon Heron
01-11-2014, 01:51 PM
I put in a top of the line commercial Bosch Pro-tankless unit about 6 years ago (GWH635ESL 175,000BTU), I hate it and would never recommend one. I have never had to touch it as far as maintenance but any efficiency gained by not keeping a tank of water hot is lost with the amount of water you have to run before you get hot water out of the taps. Also because they never run out of hot water the family now takes endless showers...
The only advantage I see with tankless is they take up very little room compared to a standard water heater.
If you get one look for one that has a small tank that keeps the water hot, that way you dont waste so much water waiting for it to get hot.
I thought at first that it was taking so long to get hot water because all of my plumbing was 3/4", so I went and took the time and $$ to change them all out for 1/2" lines and it made very little difference. Also I needed to remove the water saving reducer orifices in the shower heads and faucets to make sure there was enough flow to start the heating, the anti scald valves can also play hell with them by making them cycle on and off thus shutting the unit down until you turn the hot water tap all the way off and back on again, not fun when your in the shower and the icy cold well water hits your package... :o
If I was to do it all over again I would have put in a 40 gallon oil fired tank (runs off my biodiesel), they never run out of hot water like a tankless except there is only a 10 second wait time to get hot water.
[/rant]
Cheers,
Jon

Sparky_NY
01-12-2014, 07:41 AM
The delay in getting hot water with a tankless is often over stated. From the time you open the faucet, the tank goes through its ignition process, and full temp hot if flowing out of the TANKLESS, is actually about 10 seconds or less. That 10 seconds can seem like a long time. As for water wasting during that wait time, of course that is true BUT, if your showerhead flows 3GPM then the waste in 10sec is pretty minimal and certainly not expensive. The pipe length can add to the delay of course, but that delay would be identical regardless if its a tank or a tankless.


Tankless heaters come on at 1/2 GPM flow or less and even the new water saving shower heads flow well over 1/2GPM so if the tankless is going on and off we are back to the problem of a poor installation. One of the things I noticed most about using a tankless was how the temperature in the shower NEVER changed the slightest amount from start to finish, regardess of how long a shower. Such is the nature of a tankless. The outlet temp of a tank vaires as the water is drawn out over time, they do not have the recovery rate to maintain temperature.

IF the anti scald feature in a faucet is causing the tankless to turn on and off, well that anti scald is adjusted wrong, they are adjustable. In that house with 4 baths I previously mentioned, one shower did that exact behavior, it was a simple adjustment of the anit-scald ring in the fixture to cure it.

There are a lot of myths out there about tankless heaters, mostly due to poor installations. I have fixed several DIY installs that complained about performance, a quick check at the unit with a manometer quickly showed the problem. Unfortunately, nearly all the DIY installs never had a manometer used, nor the instructions followed. A few tenths of a inch water column pressure drop in the gas piping system results in a HUGE difference in the performance of the heater.

vincemulhollon
01-12-2014, 08:22 AM
a unit that was sized too small for the house

This tankless topic comes up about every 3 months here. I've had one about 10 years.

1) Cost scales quadratically or quintic or so with heating ability. Plumber works on commission / labor. He's going to quote you a system that will allow you to run every hot in the entire house wide open continuously on 32.00001 F inlet temp water and output temp set to instantly scald skin. Got two showers, two bathroom sinks, kitchen sink, dishwasher, utility sink, clothes washer, dish washer? He's going to quote all of them running simultaneously for max income to him, even if there's only two people in the house and you never run above 110. After the heart attack at the "used car" sized price, try to get something a little more sane installed. It'll be a little more than a tank, but not much. That's what I did and it works great. Its really boring, it just works. I can't operate every hot water tap, faucet, and appliance at the same time, but what do I care, that would be ridiculous. I can run 2 or 3 things at a time, and thats plenty. I probably wasted a lot of money to enable that ability, just 1 thing at a time would have been "good enough".

2) Any installation mistake or mfgr foobar or eventual failure involving an antique tank is just how it is, and mistakes happen, whatever, and its nothing to worry about and tanks are the greatest nostalgic antique ever. Any installation mistake or mfgr foobar involving a tankless means its a communist eco-hippie federal conspiracy to push a faulty technology which is universally bad for everyone, which always sounds hilariously provincial because tanks are mostly only used in the USA and are dying out in the rest of the English speaking world and the whole rest of the world uses tankless, so no surprised tankless works better, on a world wide scale no one uses tanks and they're obsolete. Like a horse drawn carriage.

3) Its a different type of machine, requires different maintenance. There's an inlet screen than takes about 5 mins to clean about twice a year if properly installed with the right shutoff valves. If properly installed there's valves and stuff to hook up a circulation pump to circulate acetic (vinegar) or citric (lemon) acid thru every couple years to scour out the innards depending on water hardness.

4) It makes noise. Not as much as the appliances connected to it, but louder than an antique tank. A very small number of people are driven insane by small amounts of noise and will do anything or spend anything to avoid it. I'd say its about as loud as an average dishwashing machine. Its quieter than the furnace its right next to, in my house, most of the time. So if its installed right under your bed in the basement, some people will go absolutely bonkers. Too bad for them. For everyone else they're fine.

5) The ones made in 1970 sucked. So did the cars made in 1970. Doesn't mean much in 2014.

Ed P
01-12-2014, 09:10 AM
As far as I'm concerned, down here in the South where we heat and cool with heat pumps, tankless water heaters are out of date. When I put in a new heat pump as far back as the 1980's I installed a closed loop ground source heat pump. It came with a small heat exchanger just downstream of the compressor. A small circulation pump was added with a thermal switch that allowed "warm" water from the hot water heater to circulate through that heat exchanger when the heat pump was running. In the summer it supplied all my hot water needs, the only cost being the electricity to run the circulating pump which was only a few watts. In the winter it still supplied my hot water needs but far cheaper than normal. I put an R-11 blanket around the tank to minimize losses. Very cheap cheap cheap.

Ed P

P.S. And it didn't make any noise!

wmgeorge
01-12-2014, 09:55 AM
Six years ago I built a seasonal cabin for my kids on my remote isolated Northern Minnesota property.
The only power we have is a 500 gallon tank of propane that runs the refrigerator, the stove, the heat and an 8 kW generator for lights, TV and the well pump.
I also installed a propane fired tankless hot water heater. A Japanese Takagi.
It worked fine until this year when it refused to light unless two faucets were open to make maximum water flow.
There is a paddle wheel inside that detects water flow and lights the unit.
I had to rig a hose to add vinegar to the unit to dissolve the lime deposits and free up the paddle wheel sensor. By the end of the season it had quit again.
Next spring I am going to use a solution of CLR to clean out the gunk before I turn on the well.
When I bought the heater it was the best in the market and one of the few. It cost $2500.
Today there are several brands that operate on natural gas or propane.
The electric tankless units do require very large currents and usually mean rewiring the house.
Be careful what you buy.
Bill
I don't have one but anyone who lives in a area with high mineral deposits needs to think before installing a tankless WH. Normal ones lime up over a number of years. Tankless run at hotter temperatures and would seem to lime up even faster. Get a high efficiency gas water heater with extra thick insulation.
Energy savings? Our bill for heating water is about $25 per month using natural gas. If I save how much a month what is my payback, Nil. Factor in the de-liming costs at the same time.

Jon Heron
01-12-2014, 09:58 AM
Sparky, You have lots of theories there, unfortunately none of which apply to my situation.
The unit is installed correctly, the propane tank is about 20' away and I have a 1" line going directly to the unit, all black iron except teh last 6' where I used 1" flex. I calculated the size required appropriately (3/4" would have sufficed but I had 1" available) and Of course when I set it up I used my U-tube and the pressure is on spec, not that that would have anything to do with the delay in getting hot water out the taps.
It will supply 170F water with 3 taps going full out in the house all day long with the only hesitation being the two minutes it takes for the hot water to come out the taps (your 10 second statement is completely out of touch with reality).
None of the anti scald devices in my house are adjustable, they are built into the shower faucets and consist of a sliding bronze cylinder between the hot and cold, I found the only way to "adjust" them was to remove it and put a dimple on the cylinder with a centre punch then re install it, the dimple on the cylinder makes a friction fit so it wont slide anymore. I still have to do the one in the shower downstairs. As it is now, to have a good shower in that one you have to run the hot water in the sink at the same time your showering so the anti scald doesn't kick off the heater...
None of these things are myths, they are facts and I am not alone in my disappointment with tankless heaters.
Cheers,
Jon

jeremy13
01-12-2014, 11:46 AM
Jon I’m with Sparky on this one I see a lot of installs. And you have something wrong in the system. So you have a sliding cylinder in your valve so you have a pressure balancing valve. And they will cause problems in the water flow. So let’s start a new thread and fix your water heater problem.

Abner
01-12-2014, 12:18 PM
My use is different than others, but might be helpful. I installed a Bosch 125,000 BTU 'S' (solar) model in a green house which is a very corrosive environment. It is used for heating water for benches for growing seedlings in a closed loop system. It needs annual cleaning but has worked flawlessly for 14 years and still looks good. Built with copper and stainless steel it is in better shape than any other heater we have. I can foresee it lasting at least another 15-20 years which I think is amazing.

The solar model is self modulating -adjusting output based on incoming water temperature. By providing variable output it can make up for lower than needed output from a solar water heating system. But you also need a storage tank and circulation pump. Circulating water from your solar panel when it is up to temp and making up for low temps because of clouds etc. with the tankless. Something to consider if you foresee solar down the road.

The concept would be similar to a nat. gas fired electrical generator to make up for low wind power on today's integrated power grid.

edit: Some houses utilize an insulated closed loop circulated system. With taps off the loop for sinks, etc. giving you almost instant hot water all the time. Something to consider if your want to install a bidet.;)

Sparky_NY
01-12-2014, 01:27 PM
Sparky, You have lots of theories there, unfortunately none of which apply to my situation.

It will supply 170F water with 3 taps going full out in the house all day long with the only hesitation being the two minutes it takes for the hot water to come out the taps (your 10 second statement is completely out of touch with reality).

Jon

If its supplying 170F water then it certainly is not installed properly!! No further comment should be necessary there, 170F says it all.

Reread my statement, I said 10 seconds to be coming out the TANKLESS, not out the tap!! There is a lot of posts by tankless owners in this thread, how long from the time you open the faucet until the line AT THE TANKLESS is way to hot to touch? The ones I have seen, several brands, are approx 10 seconds, what do the other owners say?

Jeremy addressed the difference in a anti-scald feature and a balancing valve so I won't comment further.

Jon Heron
01-12-2014, 01:29 PM
Jeremy, I think this thread is as good as any?
IMO, there is nothing broke that needs fixing, its just the nature of the beast. There are options available to fix the known problem's and it consists of a circulating pump and small storage tank, that just defeats the purpose of the "on demand" heater to begin with though...
That being said I will entertain any suggestions you may have.
RE the balancing/anti scald valve, I already know how to fix that as I stated above.
Cheers,
Jon

Sparky_NY
01-12-2014, 01:30 PM
As far as I'm concerned, down here in the South where we heat and cool with heat pumps, tankless water heaters are out of date. When I put in a new heat pump as far back as the 1980's I installed a closed loop ground source heat pump. It came with a small heat exchanger just downstream of the compressor. A small circulation pump was added with a thermal switch that allowed "warm" water from the hot water heater to circulate through that heat exchanger when the heat pump was running. In the summer it supplied all my hot water needs, the only cost being the electricity to run the circulating pump which was only a few watts. In the winter it still supplied my hot water needs but far cheaper than normal. I put an R-11 blanket around the tank to minimize losses. Very cheap cheap cheap.

Ed P

P.S. And it didn't make any noise!

I recently worked on one of those "Water Furnace" brand systems with domestic hot water. That is one slick system!

Jon Heron
01-12-2014, 01:40 PM
Sparky, mind the typo, 140F is what I meant.
I am talking out the tap, where it counts, it takes 2 minutes minimum to get hot water from my kitchen faucet that is literally only 20' of 1/2" pex from the tank header.
The purpose of the balancing valve is to prevent scalding when the pressure in the cold water line drops AKA anti scald valve. Mixing valves are adjustable, the balancing type used in most faucets around here (its code) are not adjustable, at least any I have seen.
Cheers,
Jon

Sparky_NY
01-12-2014, 01:48 PM
Sparky, mind the typo, 140F is what I meant.
I am talking out the tap, where it counts, it takes 2 minutes minimum to get hot water from my kitchen faucet that is literally only 20' of 1/2" pex from the tank header.
The purpose of the balancing valve is to prevent scalding when the pressure in the cold water line drops AKA anti scald valve. Mixing valves are adjustable, the balancing type used in most faucets around here (its code) are not adjustable, at least any I have seen.
Cheers,
Jon

Ok, glad to hear that 170 deg was a typo !! As for the two minutes, a couple of things you mentioned are known troublemakers. Kitchen faucets.... many of the new ones have restrictors in them, some actually have as small as a 1/4" path through them. I put a new kitchen faucet in my house and its low flow made the tankless kick out sometimes, fix was to remove the restrictors. I am probably generous saying 1/4" path, the faucet I installed in my kitchen was one of those where the sprayer was built in the nozzle arm and pulls out, its hose was maybe 1/4 outside dia !!

Pex is not a favorite of mine. Although it is real nice stuff to work with, the pipe itself is 1/2" just like any other piping BUT the fittings are barbed and go INSIDE the pipe, the hole through the brass fittings is way less than half inch. Every fitting in a pex system is a flow restrictor !!!! I suppose that could be worked around by running 3/4 pex for everything but that increases the cost a lot. The highly restrictive fittings is my BIG gripe with pex. It "may" be contributing to the problems you are having.

Jon Heron
01-12-2014, 02:02 PM
I already removed all the water saving restricting disks due to the issue with them and tankless heaters. It was a real bitch on my kitchen faucet cause it was built into the seal at the base of it. I tried to drill it out instead but the bit caught and ripped the seal which led to me having to make a custom seal anyways... Not fun.
As far as the pex goes, I used all shark bite fittings which go on the OD of the pex and cause no more restriction then a standard copper fittings. Dont forget as I previously stated the only reason I even have pex was because I replaced all the original 3/4" copper lines with this to try to reduce the wait time for hot water (less water to move).
I really wanted to love this thing, I did a considerable amount of research and spent considerable money on the one I purchased at a time when money was tight. My family complained incessantly for 3 years before I could finely admit that it sucked...
If they were as great as they sounded you would not have to tamper with and remove the anti scald valves, water saving orifices, etc and still have to wait forever to get hot water, they would just work great right out of the box. Just like the 40gallon gas water heater I removed to install this POS... :)
Cheers,
Jon

Sparky_NY
01-12-2014, 02:07 PM
Yup, sharkbite fittings cure the restriction problem, but at a very expensive cost. Love the sharkbite fittings, just not the price.

Ok, lets ask this..... if you "slam" open a faucet and hold your hand on the hot pipe, right at the tankless,how long before it gets very hot? It should be about 10 seconds at the most if the tankless is working right. I realize the time at the faucet is longer. Time it, don't guess !

I would like to hear others response to the same question!!!!

BTW, what make is your tankless?

Jon Heron
01-12-2014, 02:16 PM
Yup, sharkbite fittings cure the restriction problem, but at a very expensive cost. Love the sharkbite fittings, just not the price.
Agreed! pricey but very convenient, especially when tying into existing copper infrastructure and you dont own a crimper.
Ok, lets ask this..... if you "slam" open a faucet and hold your hand on the hot pipe, right at the tankless,how long before it gets very hot? It should be about 10 seconds at the most if the tankless is working right. I realize the time at the faucet is longer. Time it, don't guess !
I cant remember, but it was all within its spec's, the first thing I did when I wasn't happy with the performance was to make sure the unit worked properly, and it does.
I would like to hear others response to the same question!!!!

BTW, what make is your tankless?
I listed it in the first response
I put in a top of the line commercial Bosch Pro-tankless unit about 6 years ago (GWH635ESL 175,000BTU),
Cheers,
Jon

Sparky_NY
01-12-2014, 02:20 PM
I warn customers about the delay with a tankless heater. The tankless takes maybe 10 seconds from the start of water flow until hot water is coming out the tankless outlet. It takes about a 2-3 second delay before the ignition sequence starts, then maybe 3 seconds for the ignition and flame to come to full power, then a couple three seconds before the actual outlet gets hot.

The problem is..... that 10 seconds gets ADDED to the time it took with the tank heater.... if it took 15 seconds to get hot water at the far bathroom before, it now takes 25 seconds with the tankless! Believe me, that seems like a eternity!!!!!! We are a very impatient lot, adding 10 seconds seems like forever !!! If it was actually timed, the numbers I mention would be pretty accurate.

The first tankless I installed (my own), I thought was not working for this reason. I turned the hot on, waited a few seconds, nothing! I looked around the corner, the tankless was running, looked back and steam was rising from the hot water in the sink. It just took longer than I was accustomed to my whole life. I too was impatient.

I still stand by my stance that 2 minutes is way out of wack, and if truely that long then something is wrong.

Sparky_NY
01-12-2014, 02:22 PM
I listed it in the first response
Cheers,
Jon

Ah, missed that.... Interesting is the fact that the great majority of units I installed were Bosch. I have done other makes also.

Bosch made 3 lines, the Aquastar sold thru homecenters for DIY, The pro tankless, sold through plumbing supplys, and a commercial line.e

The 635 you have is a pro series tankless, but not a commercial series unit. A real good unit though.

For what its worth, the unit I had was a 425 pro series, smaller (130K btu) and standard venting type. I didn't need the additional BTU's.
I no longer have that house, moved to SC back in March. Had the tankless for almost 10 years at that point.

SGW
01-12-2014, 02:51 PM
We got one of these a couple of months ago: http://www.geappliances.com/heat-pump-hot-water-heater/

It's an electric water heater that uses a heat pump to heat the water -- the "air conditioner in reverse." So far it has worked very well, with no noticeable increase in our electric bill since we're no longer running the boiler with its associated electrical demands.

I'm not a big fan of tankless heaters.

RichR
01-12-2014, 03:15 PM
Hi SGW
From the How it Works section of that link:

The integrated compressor and evaporator use a fan to draw in ambient heat from surrounding air to heat refrigerant. Then the heated refrigerant runs through coils that wrap the tank all the way to the bottom, transferring heat into the water tank. This innovative process creates the same amount of hot water as a traditional electric water heater, while reducing your heating expenses up to 62%—a savings of $365* per year.
So basically in the winter when you are heating your house, this "innovative process" uses that heat as a source of BTUs to heat
the water, and then the heating system runs a little more to replace that heat.

wmgeorge
01-12-2014, 03:57 PM
He is using warm air from his house to heat his water, unless he is far enough south he had a air to air outside heat pump. The evaporator is cooling off the air gathering heat in the process, and the condenser side is heating his water. I remember the time I saw a innovative farmer run a water loop system through his chicken house, and then dumped the water into a large stock tank in his basement where it was pumped back out again. He had taken apart an air to air heat pump and placed the outside coil into the water filled stock tank. I was there to recharge the system with R-22. It worked great to heat his house with "Free" heat. ONLY the chicken house was heated with propane. Granted the propane only kicked in on those really cold days but it was not really free.

PStechPaul
01-12-2014, 04:59 PM
I don't have experience with tankless water heaters, but I thought they were generally for point-of-use, which would be very efficient and fast-acting. Here is information:
http://www.gotankless.com/point-of-use-water-heater.html
http://www.grainger.com/product/EEMAX-Electric-Tankless-Water-Heater-21HT82?s_pp=false

My electric hot water heater is in my kitchen living space, so all of the heat just supplements the other heating sources which are a combination of wood, electric, and kerosene. I can fairly easily repair or replace my HWH myself, and IIRC it was purchased in 1989 for about $300 and actually installed around 1994, and it still works fine. I had a problem originally because I had used iron pipe for unions to a copper system, and it suffered from galvanic corrosion. But I cleaned the anode rods and replaced the connections with brass, and it's been fine ever since.

The use of heat pumps (geothermal) and solar for hot water during the warm season are very good and probably less expensive than the tankless whole house systems.

And I really hate to work on those systems, because it's a "tankless" job... ;) (Sorry, couldn't resist)

RichR
01-12-2014, 05:02 PM
Hi wmgeorge
Yes, I understand that it uses warm air from the house. The point I was trying to make is that the hot water heater is being
supplemented by the home heating system. I'll bet they don't include that cost into their efficiency calculations.

loose nut
01-14-2014, 10:10 AM
Had a salesman (woman actually) come out to the house yesterday with info on these tankless heaters. Doesn't look very promising. This company only rents, rent includes basic installation maintenance and repairs, replacement if necessary (which she said is frequent) but there would be a severe cost of upgrading the gas piping into my house and the monthly rental fee is more then I spend on electricity for an "old Fashion" electric water heater. At least she was honest about it.

Unfortunately there isn't any way to put in a gas water (tank type) heater that will pass code inspection so the electric heater is staying put.

Don Young
01-14-2014, 10:17 PM
Unfortunately there isn't any way to put in a gas water (tank type) heater that will pass code inspection so the electric heater is staying put.

Have you included direct (thru the wall) and power vent (using PVC) heaters in your search for a code compliant heater? I am not familiar with your Canadian codes but here they can be installed nearly anywhere.

TRX
01-15-2014, 07:22 AM
They are more "efficient", in that they have zero to trivial storage tank losses.

On the other hand, let's say your normal gas water heater is sited in the conditioned space of your house, like a central, first floor utility room. Where does the "waste" heat go? Yeah, it heats your house. So, in the fall, winter and spring, you're reducing the amount of heat the furnace has to supply.

True. Which is why I just moved our water heater outside.

The air conditioning bills where I live are much more than heating bills, and the heat coming off the water heater (which was originally located in the kitchen) in the summer weren't helping anything.

Though the heater is now outside, there's only three feet of pipe now from the heater to the bathtub... no more waiting for the hot water to make it to the shower.

loose nut
01-15-2014, 10:39 AM
Have you included direct (thru the wall) and power vent (using PVC) heaters in your search for a code compliant heater? I am not familiar with your Canadian codes but here they can be installed nearly anywhere.

I don't have a basement only a crawlspace and it isn't high enough for a gas water heater (the electric one sits in a pit, can't do that with gas). There really isn't any other place to put a water heater in my house, at least one that will meet code.

Mr Fixit
01-15-2014, 10:28 PM
Loose nut,
have you considered the point of use instant hot water heaters that are electric? I have 1-1/2 baths a clothes washer, dishwasher and utility sink in the basement. I have 4 of the electric heaters 1, for the 1/2 bath, 2, for the main bath, 3, for the basement, 4, for the kitchen they are small in size and it does not take a lot of electricity for each one.
And remember if the service to the house is 150-200amps the total connected load is not all on at the same time so you could run a couple at the same time and not see a great increase to the electric bill.
Just thinking outside of the box on this one it has worked for the wife and I now for 3 years, never a cold shower unless she says I need it. :rolleyes:

mr fixit for the family
Chris :)

Tilaran
01-16-2014, 07:26 AM
Tank heaters are right up there with box springs and carpeting. Uniquely Idiotic.
http://2.bp.blogspot.com/_Hp83L_dyROg/Sw9KeW3TGzI/AAAAAAAAABc/PLv22uajmQw/s1600/MaxiDucha.jpg

ironmonger
01-16-2014, 09:44 AM
None of the anti scald devices in my house are adjustable, they are built into the shower faucets and consist of a sliding bronze cylinder between the hot and cold, I found the only way to "adjust" them was to remove it and put a dimple on the cylinder with a centre punch then re install it, the dimple on the cylinder makes a friction fit so it wont slide anymore. I still have to do the one in the shower downstairs. As it is now, to have a good shower in that one you have to run the hot water in the sink at the same time your showering so the anti scald doesn't kick off the heater...
None of these things are myths, they are facts and I am not alone in my disappointment with tankless heaters.
Cheers,
Jon

Jon is correct. The only adjustment in a shower mixer would be maximum output temperature, a function of the limits in the valve which is purely mechanical and has no effect on temperature beyond what I describe below.

'Anti scald valves' are a generic description of two separate but parallel functions often found in shower mixers.

There are thermostatic mixing valves which do a great job of regulating temperatures in steady state flow conditions but are completely unable to respond to rapid changes in operating conditions which may be either pressure imbalance between the hot and cold supply or rapid temperature changes.

Slower changes in temperature are generally due to inability of the hot water supply system to keep up with demand. The thermostatic mixer will generally decrease the flow of cold water in an effort to keep the outlet temperature constant. They cannot respond to spikes in flow or temperature.

Pressure balance valves respond very rapidly to pressure fluctuations. If someone flushes a toilet, thus reducing the available cold water to mix with the hot, you get hair removed. A pressure balancing valve will respond to this and adjust accordingly.

The very best mixers, read expensive, will have both features.


If you want to install a circulating system, another alternative is a gravity circulation system. By sloping the supply and return lines, installing a flow restricter, ie a balancing valve, and a timer with a solenoid valve to stop recirculation at night if you wish, the circulation takes place without much problem at all. The supply and return lines should be insulated. The return line does not need to be larger than 1/2 pipe. You may install a check valve in the return, but it may need service to allow it too operate freely due to lime deposits. I have generally not installed them. Using a smaller return will prevent most reverse feeding of water from the bottom of the supply tank, which is where it need to be connected. This system will not work without a pump in a tank-less. Well, it may circulate, but it will never have sufficient flow to cause the heater to turn on.

paul

loose nut
01-16-2014, 12:23 PM
Tank heaters are right up there with box springs and carpeting. Uniquely Idiotic.
http://2.bp.blogspot.com/_Hp83L_dyROg/Sw9KeW3TGzI/AAAAAAAAABc/PLv22uajmQw/s1600/MaxiDucha.jpg

Esplain please?

loose nut
01-16-2014, 12:27 PM
Loose nut,
have you considered the point of use instant hot water heaters that are electric? I have 1-1/2 baths a clothes washer, dishwasher and utility sink in the basement. I have 4 of the electric heaters 1, for the 1/2 bath, 2, for the main bath, 3, for the basement, 4, for the kitchen they are small in size and it does not take a lot of electricity for each one.
And remember if the service to the house is 150-200amps the total connected load is not all on at the same time so you could run a couple at the same time and not see a great increase to the electric bill.
Just thinking outside of the box on this one it has worked for the wife and I now for 3 years, never a cold shower unless she says I need it. :rolleyes:

mr fixit for the family
Chris :)

That was the first thing I looked at but by the time I get through the purchase/installation costs the pay back is a long time. When the current heater dies then I could go that way, the fact that they are not on all at once may make it do-able.