air handler coils froze up - question

[Soundguy]

well.. mine was clogged and dirty...

crossoing my fingers that's that all it was.. gross neglect

soundguy

 

[kenmac]

Reduced air flow. ie stopped up filter ,dirty evap coil or low refrigerant charge are just some of the reasons evap coil will freeze up. If your return is the correct size. then, it's probably 1 of the reasons that I listed

 

[Soundguy]

Just got home, buttoned it all back up with a clean filter, dumped some bleach down the drain line like someone sugested, though I know it's open and does flow.

fired it all up.. got cold air flowing.. pump doesn't seem to be cycling off and on fast like a car ac will when low on freon.

am going to check it every couple hours tonight to see if the air flow stops from freezing up again.

will post back int he am.

thanks

soundguy

 

[irvingj]

Sounds like you got it, Soundguy. Ditto the suggestion about leaving fan on with compressor off for defrosting.

 

[kenmac]

home ac compressors won't usually cycle on / off like auto compressors. If it has a low pressure switch it will usually stay off

 

[Bird]

home ac compressors won't usually cycle on / off like auto compressors. If it has a low pressure switch it will usually stay off

I guess my old Rheem didn't have a low pressure switch. The compressor just ran continuously when the coils were iced up and there was almost no refrigerant in the system. So of course, I had a new system installed a couple of weeks ago.

 

[Soundguy]

home ac compressors won't usually cycle on / off like auto compressors. If it has a low pressure switch it will usually stay off

good to know.

well.. I sett he ac for 76' and ran it last night from midnight to 7am.. ran fine all night.

got up a few times in the middle of the night for the call of nature and had good air flow entire time, including upon getting up this am...

figured i doged a bullet.

thanks
for the edvice everyone.


soundguy

 

[grunewald]

Reduced air flow is usually the number 1 cause for icing the coil. Now that you have it running, use a thermometer to check the return air temp. at filter or grill, then check supply air temp. in defuser blowing cold air into room. Temp. difference should be approximately 18 F. If you have 18 F difference,( this is ideal temp. difference) your unit is working good. If greater than 18 F, low air flow, if lower than 18 F, low on refrigerant or other problem. Didnt learn this at a Holiday Inn Express, been in the trade for 37 years.

 

[Soundguy]

I've seen that test.. the service guy here last year that repalced the cap on the external cooling fan did it.

good to know.

soundguy

 

[Bird]

Reduced air flow is usually the number 1 cause for icing the coil. Now that you have it running, use a thermometer to check the return air temp. at filter or grill, then check supply air temp. in defuser blowing cold air into room. Temp. difference should be approximately 18 F. If you have 18 F difference,( this is ideal temp. difference) your unit is working good. If greater than 18 F, low air flow, if lower than 18 F, low on refrigerant or other problem. Didnt learn this at a Holiday Inn Express, been in the trade for 37 years.

I have an analog pocket thermometer for checking cooling systems, and I have a multi-meter with a temperature probe that's even more accurate, but you have to get up to the outlets in the ceiling to use those, so I bought a new toy last week at Home Depot; a Ryobi IR001 non-contact, laser aimed, digital infrared thermometer.:laughing: It's a pretty neat little toy for $29.97 plus tax.