# Evaporator Coil Cleaning



## Plumber101 (Feb 25, 2009)

I never run a resident A/C below 70deg. Most brands recommend above 65 deg


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## yuri (Nov 29, 2008)

You can run them down to 50 deg F but you need a good steady load of 70 deg F in the house. In the colder climates we use a 50 deg F low ambient temp cutoff control. Make sure you rinse the coil with fresh water so no soap residue is left and check the drain port from the coil for blockage last.


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## kenmac (Feb 26, 2009)

mjbxx said:


> What is the lowest temperature for running a heat pump in AC mode? I'd like to do a foam cleaning of the evaporator coil after a careful vacuuming. The temperature will be around 60° during the week.


 

You shouldn't have to run A/C to clean the coil.. For evap. coils I use a self rensing cleaner. I may take a sprayer & spray it with a little water If it's not used for a few days


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## beenthere (Oct 11, 2008)

kenmac said:


> You shouldn't have to run A/C to clean the coil.. For evap. coils I use a self rensing cleaner. I may take a sprayer & spray it with a little water If it's not used for a few days


If you wash the coil, and don't rinse, or run the A/C to rinse it.
The cleaner can become covered with dust, and not rinse right later, when you use the A/C.

Causing more headaches.


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## kenmac (Feb 26, 2009)

beenthere said:


> If you wash the coil, and don't rinse, or run the A/C to rinse it.
> The cleaner can become covered with dust, and not rinse right later, when you use the A/C.
> 
> Causing more headaches.


 
Know what you mean.. Cleaned 1 this am. Alot of cat hair..Pulled the stuff off in shests. Then I used self rinse coil cleaner to Clean then run a/c


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## COLDIRON (Mar 15, 2009)

*Coil cleaning*



kenmac said:


> You shouldn't have to run A/C to clean the coil.. For evap. coils I use a self rensing cleaner. I may take a sprayer & spray it with a little water If it's not used for a few days


Good answer Kenmac. That's what I do.


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## mjbxx (Jan 20, 2009)

beenthere said:


> If you wash the coil, and don't rinse, or run the A/C to rinse it.
> The cleaner can become covered with dust, and not rinse right later, when you use the A/C.
> 
> Causing more headaches.


I plan on using the CAL-SPRAY "evap foam no rinse" evaporator coil cleaner. After spraying the evaporator coil, how long should I wait before turning the AC on to aid in rinsing? How long of a run time before the coil would be deemed fully rinsed?


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## beenthere (Oct 11, 2008)

Before you use foaming spray.
better have some plastic. Yo prevent it from running on to the furnaces HX.

It tends to over flow the drain pan.

How long to let it on, depends on how dirty the coil is.

10 to 15 minutes run time, depending how humid the day is.


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## mjbxx (Jan 20, 2009)

beenthere said:


> Before you use foaming spray.
> better have some plastic. Yo prevent it from running on to the furnaces HX.
> 
> It tends to over flow the drain pan.
> ...


The coil sits under the blower and above the filter rack. I have already vacuumed and brushed the coil and the fins don't look overly dirty. What would be an average foam spray set time according to this information? This Friday will have temps in the low 70's with relative humidity over 50%. Am I right to assume this would be an ideal time to run the heat pump in AC mode to aid in rinsing the coil?


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## beenthere (Oct 11, 2008)

It should be a good time.

Can't predict how long it will take to clean, from a descrition.

What you call not overly, may be pretty bad.

You may be surprised at how much dirt is inbetween those fins.


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## mjbxx (Jan 20, 2009)

I cleaned the evaporator coil with CAL-SPRAY, http://www.acmeref.biz/public/acmepu...l_evapfoam.pdf "evap foam no rinse" evaporator cleaner. After much research, I found that the proper way to clean the evaporator coil for my upflow heat pump was from underneath the A-Frame. The outdoor temp was 75° and ideal for running the AC for thirty minutes to rinse the coil after applying the no rinse foam spray (allowing 10 minutes for foam to set on the coil). I went one step further by utilzing a garden hose to thoroughly rinse the evaporator coil from underneath. Done!


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## beenthere (Oct 11, 2008)

One quick question.

Has anyone added refrigerant to the system i the last couple years.


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## mjbxx (Jan 20, 2009)

beenthere said:


> One quick question.
> 
> Has anyone added refrigerant to the system i the last couple years.


No added refrigerant since sytem install. Why do you ask?


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## beenthere (Oct 11, 2008)

Lots of techs gas and go systems that have dirt indoor coils. Because they are either too lazy to clean the coil, or don't know any better.

But, after the coil is cleaned, it can hurt the compressorif its over charged.


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## yuri (Nov 29, 2008)

And the flip side that I have seen a LOT, is when the condensor coil is washed, it then drops the head pressure and suction pressure and shows that the system is undercharged. Why some people won't spend less than $100 to get a check and catch problems AND save energy is beyond me.


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## beenthere (Oct 11, 2008)

I know what you mean.

They clean their coils. First time in 10 years.
Because they're tired of the high cooling bill for the last 6 years.

And then after it runs and becomes a block of ice.
Call you out, and complain about how much it cost to thaw the coil, find, fix the leak, and recharge the system.


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## yuri (Nov 29, 2008)

I got fooled by that once and only once when I was a junior tech. Pressures fine but only 10 deg drop across coil. Plugged condensor simulated a load on the unit and gave me proper pressures. Plugged evap coil can be misleading also. Impossible to talk my junior techs thru all the different scenarios. Nothing beats experience.

Cheers


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## Chemist1961 (Dec 13, 2008)

Yuri what's your mileage charge for a house call west of Toronto?
You won't need hip waders if you come here


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## yuri (Nov 29, 2008)

Actually it is a bit slow now. What is west of Toronto> Hamilton (too smelly LOL). They doubled the size of the Red River Floodway so we are okay. Going to be hordes of mozquitoes if it stays wet, oh Joy!


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