Heat Pump Defrost

[riderman]

My Goodman H\P (installed this summer\fall) was checked out\tuned up 3 weeks ago by a reputable HVAC company. The tech was here for about 3 hours. Very thorough, did SH calc's and all.

I have 90 degree air from the suppy right now and outdoor ambient is 37. I'm happy.

The issue is, the thermals dont seem to be kicking in while in the defrost mode. The supply temp drops a few degrees while in the defrost mode and the AUX LED does not light.

Raise the TS temp by 3 degrees and the AUX LED lights, and you can feel the thermals kick in (hot air). Switch to emegency heat, thermals kick in, H\P (outdoor unit)shut's off, AUX heat LED lights (with the red emergency LED)

The only problem the tech found was a defective AH fan run cap out of spec. He replaced it under warrantee.

Any clues to why in defrost mode the thermals dont kick in? Under contract, they will be here Monday. Was just wondering you Guru's opinion's.

[jacob perkins]

Originally posted by riderman
The issue is, my thermals


you get thermals when you buy a goodman?
hmmms..all mines worn out in crouch, I need me some new ones.



the auxillery/emergency is not the same circuit as defrost
you could have bad relay or wiring issue
or you could be worrying needlessly...what is the air temp during a defrost? If it aint 'refrigerator cold' then the heaters are working

[riderman]

you get thermals when you buy a goodman?
hmmms..all mines worn out in crouch, I need me some new ones.

LOL. That's my type of humer.LOL

the auxillery/emergency is not the same circuit as defrost
you could have bad relay or wiring issue
or you could be worrying needlessly...what is the air temp during a defrost? If it aint 'refrigerator cold' then the heaters are working

Your probably right jacob. I'll measure it (supply temp) next time while in defrost mode. The old HP, when in DF mode, the aux led would light.

[beenthere]

If its only bringing in 5 k of strip in defrost, it won't give you a 20 degree temp rise while in defrost.

[riderman]

beenthere

You may be correct. On the old H\P The original HVAC contractor installed an outdoor thermostat that would only kick on all 10K of the thermals below 35 degrees while in the defrost mode. Above 35, only 5K would kick on.

The HVAC installer of my new H\P cut the thermocouple to the outdoor stat in half (by mistake) while installing the outdoor unit. He stated that it would be ok.

It was 80 degrees ambient at the time and the outdoor stat's contact's were closed. He wired it back in and said it would be fine.

Now, I wonder, based on your input, if that's my problem.

[beenthere]

Strange that they would have been closed at 80° OD temp, they shouldn't close until the temp drops below the set point.

[riderman]

Beenthere stated:
Strange that they would have been closed at 80° OD temp, they shouldn't close until the temp drops below the set point.

Thanks for the reply!

That may be the problem. No question though, the contacts were closed. The installing tech showed me at the time. The company rescheduled tech assist\repairs for tommorrow.

[mark beiser]

The thing they cut in half on the outdoor thermostat is the sensing bulb, it is a closed tube filled with a gas that changes pressure as the temperature changes. It no longer has any pressure in it, wich is why the contacts were closed at 80º, and will remain closed at any outdoor temperature.

The outdoor thermostat is not "ok", it is ruined...

[riderman]

The outdoor thermostat is not "ok", it is ruined

Thanks for the advice. The tech came out today while I was at work, probably a good thing (big grin).

My wife said he turned up the Tstat to 80 degrees, went in the attic, and said that all 10 K were on.

HMMM, shouldnt he have tripped it into the defrost mode then checked to see if all 10 k were on? Can I have them come back out and just remove the OD Tstat?

Thanks

[mark beiser]

Originally posted by riderman
My wife said he turned up the Tstat to 80 degrees, went in the attic, and said that all 10 K were on.

Well duh, with the sensing bulb cut the contacts are permanently closed. He could have turned it down to 0º and all 10 KW would have still come on if he tried it when it is 100º outside, lol.