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View Full Version : OT- Cleaning Evaporator Coil



rws
04-09-2019, 04:13 PM
I want to clean the evaporator coil in my heat pump. It's not easy to get to, so I made up a spray wand that fits a pump up sprayer and a 90 degree turn, so I can spray a cleaning solution direct into the coil fins and not at an angle. Then I would flush it out the same manner.

My question is, what would be a proper cleaner? Thoughts are Simple Green diluted, or dish washer detergent (no foaming), or laundry detergent, or? I want to clean but not harm the aluminum fins. Suggestions please?

Joe Rogers
04-09-2019, 05:07 PM
There is a specific product designed for coil cleaning available from HVAC suppliers. I lost the packaging for the cleaner I bought and only have the remainder in a spray bottle so I can’t quote the brand.
Joe

Sparky_NY
04-09-2019, 05:07 PM
Evaporator coil cleaner comes to mind. Its readily available and made for the purpose.

mattthemuppet
04-09-2019, 05:22 PM
this is what I used, also with a pump sprayer
https://www.amazon.com/Nu-Calgon-416808-Evaporator-Power-1-Gallon/dp/B00L4G8QI2/ref=sr_1_6?crid=2RTYGRG6O9GBV&keywords=hvac%2Bcoil%2Bcleaner&qid=1554844795&s=gateway&sprefix=HVAC%2Bcoil%2Caps%2C163&sr=8-6&th=1

works well, doesn't harm the fins and gets flushed out with the condensate. My house HVAC evaporator had an inch thick layer of animal fur, dust and mold on it from the previous owner not using a properly fitting filter. Took a while to scrub it off but the HVAC works alot better now (unsurprisingly). I give it a soak and scrub once a year. You can also use it on the outside unit too.

Corbettprime
04-09-2019, 06:11 PM
DO NOT USE HOUSEHOLD CLEANERS! coil cleaners for aluminum are neutral to slightly acidic. Home Depot has a coil cleaner back in the plumbing section. Lowes probably does too. HVAC supply houses will carry several different brands, but are usually located in major metro areas.

CCWKen
04-09-2019, 07:28 PM
this is what I used, also with a pump sprayer
https://www.amazon.com/Nu-Calgon-416808-Evaporator-Power-1-Gallon/dp/B00L4G8QI2/ref=sr_1_6?crid=2RTYGRG6O9GBV&keywords=hvac%2Bcoil%2Bcleaner&qid=1554844795&s=gateway&sprefix=HVAC%2Bcoil%2Caps%2C163&sr=8-6&th=1

works well, doesn't harm the fins and gets flushed out with the condensate. My house HVAC evaporator had an inch thick layer of animal fur, dust and mold on it from the previous owner not using a properly fitting filter. Took a while to scrub it off but the HVAC works alot better now (unsurprisingly). I give it a soak and scrub once a year. You can also use it on the outside unit too.
Thanks Matt! Just ordered mine. :D

Dane Bramage
04-09-2019, 11:04 PM
This is what the HVAC guys use around here. The coil cleaner is from a different company. The deodorizer/antibacterial is sprayed on when done supposedly to inhibit bacteria and mold. I had something, probably mold, that was making me systemically ill. I don't have anything to compare it to but it seemed to work okay. Has to be reapplied periodically. Nu-Calgon seems to have a number of products IIRC.

The local installer said the A-coil really needs to be removed from the unit to get a complete cleaning, but it didn't seem to make a big difference from cleaning it in place.
http://pages.suddenlink.net/wpahpff/aircond.jpg

Joe Rogers
04-10-2019, 08:46 AM
Remove the A coil? Seems like a $ generator to me...requires an evac and recharge with a recycle fee. Plus the mechanical labor. Wow! I’d like to have an HVAC tech explain that and be able to justify the value added amount.
Joe

Sparky_NY
04-10-2019, 09:08 AM
Remove the A coil? Seems like a $ generator to me...requires an evac and recharge with a recycle fee. Plus the mechanical labor. Wow! I’d like to have an HVAC tech explain that and be able to justify the value added amount.
Joe

Ok, I will explain it. Most times it is NOT necessary to disconnect the lines and so no evacuation or recharge is necessary. There is usually plenty of slack on the lines to allow removing the covers and pulling the coil nearly all the way out of its case. In that position the underside of the coil can be accessed and cleaned also which cannot be done generally without pulling the coil out. Its not uncommon to find something similar to a wool blanket on the coil underside which peels off quite easily once access is gained, then a normal chemical cleaning is done.

BTW Most of the dirty/plugged coil issues stem from poor filter maintenance. Those cheap $1.00 fiberglass filters are all but useless but yet the most common ones people buy. A better pleated type filter (higher Merv rating) is far more effective at stopping the dirt from reaching the coil, the real good ones even filter smoke. The root cause of a large percentage of service calls stem from poor filter maintenance, plugged drains being a big one.

Doozer
04-10-2019, 09:42 AM
Ok, now I will explain it.
The mode of failure on evaporators and condensers
is corrosion. They corrode because the tube sheets
are zinc plated steel, and the tubes are copper.
Over time, the steel corrodes and starts pinching
in on the copper tubes. Then the tubes start to
corrode and soon cell forms between the different
metals. Eventually a leak happens. Evaporators
and condensers are fragile after a few years of use.
I would not touch one or even expose one to vibration.
I sure as hell would not take one out of it's housing
just to clean it. Bad bad bad advice.


-Doozer

Doozer
04-10-2019, 09:47 AM
As to filters... the pleated paper filters are way way too restrictive.
They clog in 2 weeks. The fiberglass ones flow way more air.
The tradeoff is to clean the evaporator more often. It is not
difficult to get in there with a 100psi air hose and get it clean.
Not sure fancy cleaners are really needed.

-Doozer

Sparky_NY
04-10-2019, 09:56 AM
As to filters... the pleated paper filters are way way too restrictive.
They clog in 2 weeks. The fiberglass ones flow way more air.
The tradeoff is to clean the evaporator more often. It is not
difficult to get in there with a 100psi air hose and get it clean.
Not sure fancy cleaners are really needed.

-Doozer

Your opinions go against all the industry standards, seems you wrote your own book.

The filter opinion is especially funny, "they clog in 2 weeks" LOL That is because they are capturing the dirt they are supposed to, instead of letting it collect on the wet coil and form mud plugging both the coil and the drain. If they clog in 2 weeks, its time for you to do a little more housekeeping.

Sparky_NY
04-10-2019, 10:06 AM
Ok, now I will explain it.
The mode of failure on evaporators and condensers
is corrosion. They corrode because the tube sheets
are zinc plated steel, and the tubes are copper.
Over time, the steel corrodes and starts pinching
in on the copper tubes. Then the tubes start to
corrode and soon cell forms between the different
metals. Eventually a leak happens. Evaporators
and condensers are fragile after a few years of use.
I would not touch one or even expose one to vibration.
I sure as hell would not take one out of it's housing
just to clean it. Bad bad bad advice.


-Doozer

What you describe is known in the industry as galvanic corrosion. It became much more of a problem over the years when manufacturers went to thinner walled copper tubing often referred to as rifled tubing. The fin material is aluminum and the copper to aluminum joint is where the leaks often occur, not just on the steel end plates. IF the coil is so corroded that removing it to clean it causes a leak then the coil is extremely close to the end of its life anyway and probably already leaks.

Removing a coil is NOT a common practice, its only done for badly plugged coils as a last resort. Normal chemical cleaning is all that is normally required. Coils somewhat self clean by the condensate flowing down the fins provided they are not full of mud because of poor filter maintenance.

So, what you call bad bad advice, is widely accepted practice in the industry and follows most manufacturers recommendations. But then, I am pretty sure you are not in the industry and do have have EPA level 3 or higher licensing required by true HVAC techs. Sleeping at a holiday in express last not does not qualify.

mattthemuppet
04-10-2019, 10:51 AM
Thanks Matt! Just ordered mine. :D

you're welcome Ken!



http://pages.suddenlink.net/wpahpff/aircond.jpg

the can on the left I used 2 or 3 of first time. Helped a bit, foamed nicely too, but couldn't make much of a dent on its own. Bought the pump sprayer, the Nu-Calgon stuff and a long handled soft bristled brush and now it's about as clean as I can get it. This was definitely one that would have benefitted from being removed to clean. Still not 100% as I can't get up into the corners and there's some corrosion too, but good enough for a 14 year old unit. Hopefully it'll keep chugging along for a few more years yet.

jdunmyer
04-10-2019, 04:00 PM
My shop A/C consists of a Frigidaire belt-driven compressor condensing unit coupled up to a semi-circular evaporator that originally had a paddle fan in the bottom, drawing air upwards and blowing out through the coils. Uses R-12 refrigerant, and came out of a small walk-in cooler. The paddle fin crapped out, and I replaced it with a small furnace blower & plywood box holding 2 filters; I use the pleated type.

The unit is about 2 tons capacity, a bit more than my shop requires, so it doesn't run for long cycles, but does a heckuva job when it's 90 degrees out.

I noticed a kinda sick feeling sometimes, and figured that it was due to 'something' growing in the condensate pan. If/when I notice that, I pour a pint or so of bleach into the pan.

No idea how old this outfit is, but I'd bet on its being 70 or more. When did they quit using 'open' compressors?

johansen
04-11-2019, 02:57 AM
Ok, now I will explain it.
The mode of failure on evaporators and condensers
is corrosion. They corrode because the tube sheets
are zinc plated steel, and the tubes are copper.
Over time, the steel corrodes and starts pinching
in on the copper tubes. Then the tubes start to
corrode and soon cell forms between the different
metals. Eventually a leak happens. Evaporators
and condensers are fragile after a few years of use.
I would not touch one or even expose one to vibration.
I sure as hell would not take one out of it's housing
just to clean it. Bad bad bad advice.


-Doozer


As to filters... the pleated paper filters are way way too restrictive.
They clog in 2 weeks. The fiberglass ones flow way more air.
The tradeoff is to clean the evaporator more often. It is not
difficult to get in there with a 100psi air hose and get it clean. (and you're worried about vibration?!)
Not sure fancy cleaners are really needed.


not sure what planet you're on but you're cloging up the internet with bull S H I T.

evaporators haven't been zinc plated steel in probably 50 years, if ever.

and get some merv 8 filters or better in your system and replace them until they last a few months. maybe your respiratory system will clear out and you'll be able to smell the crap you're spraying.

Doozer
04-11-2019, 02:49 PM
Then tell is what you think the tube sheets are made out of??

-D

Doozer
04-11-2019, 02:53 PM
As for "the industry" wanting you to remove the evaporator
just to clean it, of course they what you to do that.
You might have to buy a coil and pay for a recharge
because of it. Money taking scheme in my opinion.

-D

Tom S
04-11-2019, 03:12 PM
Then tell is what you think the tube sheets are made out of??

-D

Evaporator fins are made from Aluminum sheet, not galvanized steel sheet. Have been for many years. Some manufactures have moved over completely to aluminum tubes and aluminum fins, or to microchannel tubing, but they don't have a good reputation for leak resistance.

Plus, when the aluminum sheet is punched an extruded collar is left, which when the tubing is expanded inside of the fin pack provides a larger contact area to promote heat transfer and prevents any sharp edges from contacting the copper or aluminum tubing.

I would not recommend the removal of a coil, sounds like a contractor selling extra labour. Use a cleaning chemical designed for evaporators and put a proper filter in.

Tom S
04-11-2019, 03:18 PM
My shop A/C consists of a Frigidaire belt-driven compressor condensing unit coupled up to a semi-circular evaporator that originally had a paddle fan in the bottom, drawing air upwards and blowing out through the coils. Uses R-12 refrigerant, and came out of a small walk-in cooler. The paddle fin crapped out, and I replaced it with a small furnace blower & plywood box holding 2 filters; I use the pleated type.

The unit is about 2 tons capacity, a bit more than my shop requires, so it doesn't run for long cycles, but does a heckuva job when it's 90 degrees out.

I noticed a kinda sick feeling sometimes, and figured that it was due to 'something' growing in the condensate pan. If/when I notice that, I pour a pint or so of bleach into the pan.

No idea how old this outfit is, but I'd bet on its being 70 or more. When did they quit using 'open' compressors?

R-12 was phased out around '96 if I remember correctly. Hope that it never leaks and needs a recharge, R-12 is hard to find and expensive.

Doozer
04-11-2019, 03:26 PM
I run propane in my car A/C system.
Cheap and very cold.

-D

Tom S
04-11-2019, 03:58 PM
Not your BBQ grade stuff. You need to look for R290, then you would have to check if your valves and coils are sized to use it efficiently. Please don't post things like this, people are already terrified enough of R290 as a refrigerant without someone blowing themselves up because of something they saw on the internet.

Besides, a lot of automotive manufacturers are moving over to CO2 or R-1234yf these days.

Doozer
04-11-2019, 04:11 PM
... Please don't post things like this, people are already terrified enough of R290 as a refrigerant without someone blowing themselves up because of something they saw on the internet.

...

What people believe or what they are afraid of is totally out of my control.
People already believe lots of things that don't make sense.
Just look at advertising and organized religion.
You don't have to ride with me to go to lunch in my ice cold car if you don't want to.

-D

3 Phase Lightbulb
04-11-2019, 04:38 PM
The HVAC units in my home each have a UV light blasting the air handler 24/7. Anyone suffering from any type of growth/mold/etc might want to look into adding a bath of UV to your HVAC system/air handler/etc.

jdunmyer
04-11-2019, 07:09 PM
R-12 was phased out around '96 if I remember correctly. Hope that it never leaks and needs a recharge, R-12 is hard to find and expensive.


I have some in stock, but would consider propane as a replacement. More likely, would just replace the whole outfit; the new stuff should be more efficient anyway. (although the electric bill is usually no more than $40.00 or so)

chipmaker4130
04-12-2019, 10:41 AM
. . .Just look at advertising and organized religion. . .

As opposed to disorganized religion?