Furnace and heat pump question...

[blazenut]

I just got done looking at a place that was in really bad shape (current owner is in prison and never did much to the place...). My question is this, it had an 11 year old HE carrier furnace, but it was hooked up to a 24 year old york heat pump. What issues can you run into with this as far as only using the cooling functions of the heat pump (didnt work anyway) with a newer furnace?

[Marc]

I don't see any. During those years (11 to 24 yrs ago), marrying different brands of the same tonnage was common. As for the heat pump conflict, the reversing valve is likely isolated electrically so I don't see an issue with it. I've seen some like that myself in the field, including some systems where the reversing valve was actually removed from the outside unit and the backup electric heat had become the default heat source.

At 24 years old, be on the lookout for something that will suggest the need for a new system.

Marc

[Richard Moore]

Putting energy efficiency aside and assuming everything was working and in acceptable condition, I don't see any special issues in only using the pump as an AC unit. The only real difference is that you are not exercising the reversing valve. I don't see why that would matter if you have no intention of using it.

How they have wired the thermostat to the units might be interesting though. Is the furnace still "emergency heat" or just normal "heat"?

[Marc]

Putting energy efficiency aside and assuming everything was working and in acceptable condition, I don't see any special issues in only using the pump as an AC unit. The only real difference is that you are not exercising the reversing valve. I don't see why that would matter if you have no intention of using it.

How they have wired the thermostat to the units might be interesting though. Is the furnace still "emergency heat" or just normal "heat"?

Richard, if the newer furnace is gas powered, the original York heat pump coil might still be installed. If that's the truth, then I'm with you but if the newer furnace is electric then the existing evap coil may have come with it and an ordinary AC evap coil cannot be used on a heat pump system because the expansion valve or orifice would not have the 'reverse flow bypass' feature inside of it for heat function.

What do you think?

Marc

[blazenut]

The new furnace is gas, the old york hp is shot... i recommended it be replaced. Thanks guys.