# Solved: A/C issues...freezing every 3 hours or so



## ckphilli (Apr 29, 2006)

Folks, I'm at my wits end. I spent the better part of the day taking my internal a/c portion apart. Here's what I did to give you a baseline:

1) Checked the pump, works fine.
2) Cleaned out the PVC pipe that runs from the evaporator (that's what I'm calling it anyway, not sure...upside down V shaped above the furnace; fan blows through it to cool the house). Had a little debris, but nothing ridiculous.
3) Cleaned off the evaporator. I pulled a plastic grocery store bag full of hair/dirt/assorted off of it. I thought I had it made after seeing that.

This thing is still freezing and I am out of ideas. Is there anything else I can do or do I have to call someone. I really HATE to call an a/c guy because I know for a fact the bill will be 150 at the minimum.

Please shoot if you have an idea.


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## leroys1000 (Aug 16, 2007)

Probably need to have the refrigerant pressure checked.
Low freon level can overwork the compressor.


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## ckphilli (Apr 29, 2006)

leroys1000 said:


> Probably need to have the refrigerant pressure checked.
> Low freon level can overwork the compressor.


Thanks...I was afraid of that after all the reading I've done today.


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## daniel_b2380 (Jan 31, 2003)

1. it's not getting enough air-flow through the internal exchanger coils - [normally called a-coil] - dirty / plugged coil / filters

2. possibly defrost timer / defrost control circuit board


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## Koot (Nov 25, 2007)

You most likely have a refrigerant leak, which causes the A Coil to ice up.

If you do learn that your problem is a refrigerant leak - have the system tested to find out where the leak is...and have it repaired/replaced. The refrigerant is in a closed-loop and is not supposed to leak-out unless there is a problem (hole/loose fitting) that allows it to escape.


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## ckphilli (Apr 29, 2006)

daniel_b2380 said:


> 1. it's not getting enough air-flow through the internal exchanger coils - [normally called a-coil] - dirty / plugged coil / filters
> 
> 2. possibly defrost timer / defrost control circuit board


I cleaned # 1. It's blowing a LOT harder now but still freezing.

Can you point me towards the defrost timer/defrost control circuit board? Do all a/c units have them? I should probably add this unit is 10-15 years old.


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## ckphilli (Apr 29, 2006)

Koot said:


> You most likely have a refrigerant leak, which causes the A Coil to ice up.
> 
> If you do learn that your problem is a refrigerant leak - have the system tested to find out where the leak is...and have it repaired/replaced. The refrigerant is in a closed-loop and is not supposed to leak-out unless there is a problem (hole/loose fitting) that allows it to escape.


Yup, I hope this isn't the case but everything points in that direction.


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## daniel_b2380 (Jan 31, 2003)

ckphilli said:


> ....3) Cleaned off the evaporator. I pulled a plastic grocery store bag full of hair/dirt/assorted off of it. I thought I had it made after seeing that.....


are you speaking of the indoor or the outdoor unit here?
the outdoor unit very seldom gets any accumulation of debris
it's the indoor unit that gets the accumulation of debris such as you spoke of - [and if one has pets, it gets really bad real quick]
but how did you get an accumulation like this? do you replace the filters regularly?



ckphilli said:


> I cleaned # 1. It's blowing a LOT harder now but still freezing....


did you then use an air compressor to blow it completely clean?
you may need to buy some of the cleaning solution to get it clean enough if it was as bad as you stated in your first post - [you can use a small brass brush - NOT WIRE - and a dish-soap & vinegar solution similar to what one would use for cleaning windows]

is the big fan on the outdoor unit working - a common occurance is the start capacitor goes bad



ckphilli said:


> ....Can you point me towards the defrost timer/defrost control circuit board? Do all a/c units have them? I should probably add this unit is 10-15 years old.


with all the different units on the market, getting into this part of the job is really at a tech's level and much more than usual homeowner can deal with

these units are part of the circuit controls that direction of the reversing valve
couple pics:
Heat Pump Defrost Timer
http://americanhvacparts.com/Mercha...PROD&Product_Code=HH25UC115&Category_Code=HPP

Heat Pump Defrost Control Circuit Board 
http://americanhvacparts.com/Mercha...OD&Product_Code=CIB32FA006A&Category_Code=HPP

a 'cheap' check of this circuitry would be to maybe every hour or so to change it from ac to heat for about 5 to 10 minutes - then back to ac



ckphilli said:


> ....I should probably add this unit is 10-15 years old.


when was the last time that you had this unit serviced?

it's possible that the collector tank / accumular has 'rusted' and has a small leak - lowering the refridgerant level - usually when this happens, the unit just runs and runs without accomplishing any heating or cooling

checking the refridgerant amount is not really hard, if you have a friend in either home OR automotive refridgeration - the gauges are the same - takes maybe 5 to 10 minutes to hook them up and take a reading - question answered


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## JohnWill (Oct 19, 2002)

The times I've had the coils freezing, it's been low on freon. That's the most common cause if you've done all the obvious housekeeping, cleaning, etc.


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## ckphilli (Apr 29, 2006)

Thanks for the inputs folks. I'm going to get a hold of an a/c guy to get refrigerant added. There just isn't any other explanation at this point. It's running, it's clean, inside and out. It doesn't freeze nearly as often now...but I don't want to cook the thing if it is low.

Thanks again-


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## Koot (Nov 25, 2007)

Don't "just" have the A/C technician add refrigerant - have him find where the system is leaking and repair it. If you don't have it repaired - you will be adding refrigerant again...and again...and again...and again.


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## ckphilli (Apr 29, 2006)

Koot said:


> Don't "just" have the A/C technician add refrigerant - have him find where the system is leaking and repair it. If you don't have it repaired - you will be adding refrigerant again...and again...and again...and again.


Gotcha:up: Thanks-


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## daniel_b2380 (Jan 31, 2003)

post back and let us know how you got on


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## ckphilli (Apr 29, 2006)

daniel_b2380 said:


> post back and let us know how you got on


The charge was all it needed:up: No leaks so far as he could tell:up: The house is nice and cool and the a/c doesn't have to work overtime. All the cleaning I did was not in vain...hopefully it will help to keep this thing going until we can afford a new unit.


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## Koot (Nov 25, 2007)

Refrigerant does not just go away for no reason...without a leak. You should never have to add refrigerant - because refrigerant does not dissipate. Your technician just didn't spend a lot of time determining where the refrigerant was leaking...maybe because you didn't want to him to spend the time to find the leak. It will most definitely leak-down once again and cause the same icing-up problem. Depending on the size of the leak it could be as soon as a few days from now to next season, but you'll have problems again.


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## ckphilli (Apr 29, 2006)

Koot said:


> Refrigerant does not just go away for no reason...without a leak. You should never have to add refrigerant - because refrigerant does not dissipate. Your technician just didn't spend a lot of time determining where the refrigerant was leaking...maybe because you didn't want to him to spend the time to find the leak. It will most definitely leak-down once again and cause the same icing-up problem. Depending on the size of the leak it could be as soon as a few days from now to next season, but you'll have problems again.


Hey now, don't ruin my day...it's 99 in the shade here and I'm cool as a cucumber. Just kidding and I thought the same thing you said. I just really want to get this thing to the end of the season; I'm certainly not discounting your words. I just hope it's a small leak.


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## Koot (Nov 25, 2007)

Yep, over a 100 here...but low humidity. 

It can be very difficult to find a small leak, but even a small leak is not a good thing. Also, there is a window of time when a system that low on refrigerant will actually produce extraordinary coolness. That's why technicians (with the aid of the manufacturer's specifications) tweak the system to operate at the highest performance. This perfromance tweak you could say is somewhat a fine-line between having a system with too much refrigerant and not enough.

Hopefully your A/C had not been serviced for many, many years and refrigerant leaked-out over many years through an extremely minor hole in a fitting...versus leaking-down over a brief few weeks or months. If you are still cooling nicely at the end of the summer, and in particular next spring, I'd say you're lucky, which indicates the leak-down occured over many years and wasn't previously found (until now) because it hasn't been serviced for many years.

Good luck with it! Stay cool...


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## JohnWill (Oct 19, 2002)

Actually, depending on how big the leak is, it could take years to leak down. However, the observation that there is a leak is certainly correct, no way it just "disappears".


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## leroys1000 (Aug 16, 2007)

All pressurized systems slowly lose pressure over time.
There isn't any such thing as a perfect seal or a perfectly
air tight material.
That is why it is recommeded that the systems have an 
anual service check.
Frankly,every 5 years is probably good as long as the
unit is properly maintained.
I'd like to never have to put air in my tires,but it aint gonna happen.
Ha Ha


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## JohnWill (Oct 19, 2002)

FWIW, I have two 20 year old heatpumps, (Lennox) and they have worked without any maintenance for all 20 years. I recently had them checked, and one was down several pounds of freon, but the other was fine.

I'm currently working on bids to replace them with high efficiency units, I figure they don't owe me anything!


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## chfd (Aug 9, 2009)

This is usually due to a dirty air filter. Not enough air flow.


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## JohnWill (Oct 19, 2002)

Losing freon has nothing to do with a dirty air filter.


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