What should the output temperature be?

[jechow]

I have a 3 ton York Affinity HP with a 3 ton indoor coil. If the manufacturer's specs state that if:

1. The air temperature entering the outdoor coil is 40F;
2. The air temperature entering the indoor coil is 70F; and
3. The CFM is 1400

Then the air going into the duct system should have 34.4 MBTUH. What range of temperatures should be measured at the supply registers? For my home I am getting 73F when the HP first starts up and 66F soon after. I think that there is a problem here?

[Shophound]

I have a 3 ton York Affinity HP with a 3 ton indoor coil. If the manufacturer's specs state that if:

1. The air temperature entering the outdoor coil is 40F;
2. The air temperature entering the indoor coil is 70F; and
3. The CFM is 1400

Then the air going into the duct system should have 34.4 MBTUH. What range of temperatures should be measured at the supply registers? For my home I am getting 73F when the HP first starts up and 66F soon after. I think that there is a problem here?

Going by the numbers you gave, and predicated that the system is indeed cranking out 34,400 BTUH with 70 degree return air, you should see around 93 degrees leaving the indoor coil. That's at the coil. The supply register temperature will likely be lower if the duct runs are in a non-heated area, such as an attic or crawl space.

Even with 93 leaving the coil, 73 to 66 at the register is way too low. If you have 70 going in and 66 coming out, you're actually cooling the air. That's not good for a heat pump that is supposed to be adding heat to the air, not removing it.

You need to have your system serviced by a competent pro. Have him check the ductwork as well.

[buttwheat]

Yes it sounds like you got a problem.

[weber]

With temps like that you might want to switch to emergency heat and call someone to come out. Your not going to heat your house if your #s are correct, so you are cooling house down enough intil aux heat kicks in then your fighting against the cold hp.

Try wasting as less of electric as you can.

[jechow]

Has anyone diagnosed a similar problem? What is most likely the issue? Could it be too much or too little freon? Could it be a damaged A-coil or HP compressor?

[bobb25]

Similar problems are diagnosed all the time. Your particular problem needs to be diagnosed by a technician at your home.

[beenthere]

Several things can cause that to happen.

The first thing is a dirty air filter.
If its something other then that, you need a tech to check it out.

[Mrfixit39]

check charge

[beenthere]

He's the home owner.

He shouldn't be checking the charge.

[jechow]

The person who installed the system is coming over. When he comes over, I will make sure that he checks the charge. Thanks MrFixIt39.

By charge, you means pounds of freon in the system. Correct?

[BaldLoonie]

My old King is a purring along. It's 25° out and with 450 CFM/ton airflow she's putting out air 24° warmer than going in. Not bad.

[beenthere]

My old King is a purring along. It's 25° out and with 450 CFM/ton airflow she's putting out air 24° warmer than going in. Not bad.

Yea, but you got your stat set at 60*, some people like it a bit warmer in the house.

[jechow]

My home originally had a furnace. I replaced the furance with a duel fuel HP system. The installer is saying that the reduced output temperature at the registers (as descirbed above) is due to my undersized ducts.

Does this make sense? If this is true and we assume that the HP system is working properly, where did the heat energy from the A-coil go?