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Pantera99 10-01-2011 05:59 PM

Heat Pump blows cold for awhile
 
Hi all! I'm the proud owner of a crappy 3 ton Ducane heat pump that is under 7 yrs old. Had a major R22 leak last fall, had the leak repaired, refilled w 7#s of freon. Replaced contactor, condenser fan, a capacitor and defrost control board because it had a large black burn mark when fan went out. Had been running fine until recently. Also the unit doesnt seem to drain properly, there's always alot of condensation lying at the bottom of the unit. Some of it drains off but not all. Doesnt appear to be any obstruction in the pvc drain tube. It's a rooftop unit, brilliant in the sonoran desert:huh:
So the problem now is that it runs fine & cold for the 1st 20 mins or so (17-18deg split) and then slowly starts to blow warmer until its about a 5 deg split & it just runs until it blows warm. Filter is brand new so Im not sure if its freezing or low on freon again or what. Then I'll shut it off for an hour or so, turn it back on & its fine for awhile & repeats the same thing again.
Any ideas would be greatly appreciated, thanks!! 1340 sq ft, 1 floor

Master of Cold 10-01-2011 06:15 PM

I would suspect moisture in the refrigerant system.

Pantera99 10-01-2011 06:32 PM

Quote:

Originally Posted by Master of Cold (Post 739714)
I would suspect moisture in the refrigerant system.

"In" the refrigerant system? Like inside the pipes? Or inside the unit itself? IDK if the drain pan is leaking or perhaps the whole unit isn't level. The excess water in the unit sure can't be helping. If u mean inside the pipes, what can be done about that? IDK alot about HVAC so forgive me if this is a stupid question, thanks!!

JJboy 10-01-2011 06:57 PM

If moisture is found inside the system (mixed with refrigerant ). All refrigerant has to be recovered . After that, unit needs to be triple evacuated with 500 microm on the last cycle. Then reload the unit with new refrigerant. Also is good to add filter drier.

Master of Cold 10-01-2011 07:07 PM

If you work for me, filter drier is mandatory...

JJboy 10-01-2011 07:16 PM

Quote:

Originally Posted by Master of Cold (Post 739771)
If you work for me, filter drier is mandatory...

:thumbup:

Pantera99 10-01-2011 08:58 PM

Quote:

Originally Posted by JJboy (Post 739760)
If moisture is found inside the system (mixed with refrigerant ). All refrigerant has to be recovered . After that, unit needs to be triple evacuated with 500 microm on the last cycle. Then reload the unit with new refrigerant. Also is good to add filter drier.

Wow, ok I never even thought about that. That would certainly explain why it acts sporadically. I would assume R22 had some sort of moisture repellant in it, I know it has some sort of mineral oil or something but I guess it doesnt. I've popped off a panel when I thought it was 'frozen" but I was looking for ice on the outside of the evap coil & if anything its overly wet on the bottom of the unit getting into the unit's insulation. Every time I shut it off for an hour or so its fine upon startup again. I know how to get ahold of a couple of HVAC techs, I'll run this idea by them. Thanks for the help. Every time I call a company out they just wanna sell me a new unit. I'm like it's 6 freakin' years old ya know??:wallbash:

JJboy 10-01-2011 09:07 PM

Quote:

Originally Posted by Pantera99 (Post 739871)
Wow, ok I never even thought about that. That would certainly explain why it acts sporadically. I would assume R22 had some sort of moisture repellant in it, I know it has some sort of mineral oil or something but I guess it doesnt. I've popped off a panel when I thought it was 'frozen" but I was looking for ice on the outside of the evap coil & if anything its overly wet on the bottom of the unit getting into the unit's insulation. Every time I shut it off for an hour or so its fine upon startup again. I know how to get ahold of a couple of HVAC techs, I'll run this idea by them. Thanks for the help. Every time I call a company out they just wanna sell me a new unit. I'm like it's 6 freakin' years old ya know??:wallbash:

6 years old is a baby system. :thumbsup:


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