Who works on HVAC?

[ibrokeit]

We bought a house with a not-very-old split unit heat pump about 2 years ago. After we lived her a few months, the performance dropped. Called the local HVAC folks and they said it was low on refrigerant. Great but why? Didn't know. So they topped it off and it went back to working. Another few months goes by and same deal. This time they put dye in it I believe. Another few months and same deal again. That come out and say its the compressor coil (I think thats what it was) that is leaking. $800 later and I am back in business.

All summer, the AC has struggled bad to keep up. Running all the time. Here recently, though, a new problem has started. It will be working ok, keeping the house where I set it. I will go to bed and wake up the next morning with the house hotter than hell. The vents are blowing, and the outside unit is running, but no cold air. If I then turn the unit off for about 5 minutes and then turn it back on, it goes right back to cooling fine and starts knocking the temps in the house back down.


Any ideas? Im about at the end of my rope.

 

[Rokcrler]

Re:

Still have a leak.
Mine did the same this year from dogs pissing on the coil.
Did they find a leak in your unit?

 

[kmcminn]

I had leak on a split unit one time it was the coil under the house leaking. You could take off the inspection cover for it and the cover was corroded. I think the coil was like 1500 if I remember correctly.

 

[ibrokeit]

Still have a leak.
Mine did the same this year from dogs pissing on the coil.
Did they find a leak in your unit?

They claimed it was the compressor coil leaking, I believe. Cost me around $800.

 

[Rokcrler]

Re:

Recheck for leak.
On the unit there's the high and low pressure lines, one needs to be hotter than the other, if both warm you have a leak. The coil might have had one they found but there might be other pin holes.

 

[ibrokeit]

Recheck for leak.
On the unit there's the high and low pressure lines, one needs to be hotter than the other, if both warm you have a leak. The coil might have had one they found but there might be other pin holes.

Would that be in the attic or outside? I am leaving next monday for a Month and really want to get this taken care of before I leave.

 

[snoball]

They should do an isolation test on your system if they can't find the leak with an elec leak detector or dye. Seal off
each component indoor coil, cond, and refrigerant lines. Then each should be pressurized with nitrogen to 300 psi or so and
the leak should be pretty easy to find. Did they replace your condenser coils last time? 800 seems cheap unless it was some
kind of parts warranty and you were just charged for refrigerant and labor.

 

[ibrokeit]

They should do an isolation test on your system if they can't find the leak with an elec leak detector or dye. Seal off
each component indoor coil, cond, and refrigerant lines. Then each should be pressurized with nitrogen to 300 psi or so and
the leak should be pretty easy to find. Did they replace your condenser coils last time? 800 seems cheap unless it was some
kind of parts warranty and you were just charged for refrigerant and labor.

It wasn't a warranty job for sure. And it may have been more than $800, I really don't remember. Maybe it was the condenser coil they replaced?

 

[snoball]

We charge around $50 a lb for r-22 and a 2 ton holds over 6lb. condenser coils are usually 600-1000 our cost. Installed usually done deal between 1600-2200 hundred including the freon. If you have a thermometer that you could check air temp it should have a delta T between supply and return of at least 15 degrees up to 20 rite at the fan coil.

 

[ibrokeit]

We charge around $50 a lb for r-22 and a 2 ton holds over 6lb. condenser coils are usually 600-1000 our cost. Installed usually done deal between 1600-2200 hundred including the freon. If you have a thermometer that you could check air temp it should have a delta T between supply and return of at least 15 degrees up to 20 rite at the fan coil.

Ill check it and get back.

 

[j-mox]

If it's hot then you shut it off for awhile then turn it back on and it cools isn't that a sign of the A coil freezing up? No air flow due to ice and then once it melts off you have air flow thru the coils again?

No A/C expert but I've had one freeze up and it didn't cool but everything ran.

 

[ibrokeit]

If it's hot then you shut it off for awhile then turn it back on and it cools isn't that a sign of the A coil freezing up? No air flow due to ice and then once it melts off you have air flow thru the coils again?

No A/C expert but I've had one freeze up and it didn't cool but everything ran.

Normally, yes. But one one freezes, it needs to be left off for a while to thaw. I can cut mine off and 5 minutes later back on and it cools fine.

 

[snoball]

it may be going off in low pressure or a high pressure switch, and after you cut it off it equalized then starts back up. May have a restriction, possibly over charged, or a problem in the low voltage system like the defrost board.

 

[417chevy]

Not really sure how these work in comparison to automotive ac but could it be a weak compressor or a clog in the line maybe a ristrictuon between the fan and condenser or what ever may be used for home ac


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[5BrothersFabrication]

Mine did the same thing. Ended up being a $3 relay. Check the relay to the squirrel cage.

 

[jayphizzle]

If you still had air blowing while the unit was not cooling, it wasn't frozen up. When you cycle it off and back on, it may be resetting a safety through a defrost board. The compressor also has an internal overload that will shut down the compressor only if the internal temperature gets too hot.( low refrigerant charge, pitted contacts in contactor causing high amp draw) If this happens, the outdoor fan motor will still run and the compressor will be off. Upon cycling power after the compressor cools, the overload is reset. Can you give some more info on unit? Brand, model#. I am in Auburn frequently if you would like me to look at it PM me. Hope this helps.

 

[ibrokeit]

If you still had air blowing while the unit was not cooling, it wasn't frozen up. When you cycle it off and back on, it may be resetting a safety through a defrost board. The compressor also has an internal overload that will shut down the compressor only if the internal temperature gets too hot.( low refrigerant charge, pitted contacts in contactor causing high amp draw) If this happens, the outdoor fan motor will still run and the compressor will be off. Upon cycling power after the compressor cools, the overload is reset. Can you give some more info on unit? Brand, model#. I am in Auburn frequently if you would like me to look at it PM me. Hope this helps.

That would be great. Ill get the model number and stuff when I get home this afternoon. Shooting you a PM.

 

[wgamble]

I first say that I did not read every post prior to mine so if I am repeating someone else then my bad.

I just went through this with a rental property:

If your evaporator coil is leaking: you need to change the air filter AND go to the outside unit and take the outside metal cage off and wash the crap out of it (make sure the unit is turned completely off)
Also if your evaporator coil is frozen over, turn your fan only on for about 3 hours, this will help defrost it.

If your A/C is having a hard time keeping up and it is not freezing over then I guarantee you it is the CAPACITOR. My tenant swore up and down that the unit was out of Freon. The unit ran, coil was not frozen or anything. When I looked at the filter that his wife put in the bottom of the trash can because she knew she lied to me about changing it monthly, it was horrible.

2 things I learned from the ac man: 1) do not turn your thermostat down lower than 70 degrees ( your unit never has a chance to turn off) 2) if you have any animals in the house (especially a cat) then change your filters every 15 days.

Last but not least, go to your drain line and pour Clorox in it to kill any algae in it.