Heat Pump register air tempature?

[callbay]

I have a new 2 ton heat pump and the air temp. coming out of the register is 91 degrees. It's 37 out and 68 in the house. This heat pump has only one zone. Is that high enough? I just had the Freon checked and it was fine.

I have another 12 year old heat pump that is a five ton and has several zones with a zone panel and it has a large bypass to redirect the air back over the heat pump coil when only using one zone.

When the 5 ton is operating with only one zone open the register temperature is 122 degrees coming out of that zone.

Is this because the five tons is being concentrated in one small zone and the air is being heated by the coil and then some is bypassed back to the coil to heat it up higher?

Thanks a ton!

 

[mk378]

The laws of thermodynamics dictate that heat pump efficiency will fall as the output temperature rises. Think of a water pump pushing water to an unnecessarily high height and then letting it fall back down.

Ideally a heat pump would emit a large volume of air from the registers at just above the house temperature. But that makes the house feel drafty and uncomfortable, so compromises are made.

 

[Kuato]

mk378 is correct. At 60°F, your heatpump will work much better than at 32°F.

You are also correct; the 5 ton unit puts out more heat that the 2 ton unit, plus from the way you described it, it sounds as if the 5 ton unit heats one zone at a time, while the 2 ton unit heats the entire space. This dilution of heat also contributes.

All that said, 91°F air coming out of the ducts, all of them, should be plenty to keep a normally insulated home warm. 122 sounds a little hot to me, and could create a danger of hot registers that could burn a child.

 

[EA82]

It's also possible the one has a back up heat strip and the other doesn't.

 

[Click]

You dont say if its an "air source" heat pump or "ground source" ?
My ground source pump puts out 110 degrees at the registers even when its -20 here in Minnestoa.

 

[Yah-Tah-Hey]

I think laserred is right. At 32F, no heat pump is going to produce enough heat without supplemental heat source..

 

[sleddriver]

Originally Posted By: callbay
I have a new 2 ton heat pump and the air temp. coming out of the register is 91 degrees. It's 37 out and 68 in the house. This heat pump has only one zone. Is that high enough? I just had the Freon checked and it was fine.
Actually, that sounds too high for just a heat-pump. You're electrical back-up strips have probably kicked in.

 

[callbay]

I made a mistake. The air coming out of the five ton is 105 degrees which is 14 degrees warmer than the 2 ton.

The 122 degrees was when I tested with the backup strips on.