I have a three year old heat pump. It is connected to a programmable thermostat that is not used to alter the temp... always set at 68°. My question is, the heat pump seems to run forever and a day. The stat is reading 68° but it continues to run for what I think is an excessive amount of time.... shouldnt it shut down once the temp reads the setpoint? Do I have a bad stat? Should I go back to just a regular "unprogramable" stat?

Thanks for any thoughts!

 

plh_in

I see comments in many posts that it is normal for heat pumps to run all the time. I respectfully disagree. Your system is either undersized for your comfort level(thermostat setting), mechanical/operating issue, or a thermostat that should be changed out. If this is a DIY project, I would start with a decent stat made for a heat pump-digital is OK and programmable not necessary if you don't intend to take advantage of its features. Please no cheapie model.

My opinion.

 

I thought that I had read in other posts that it is not a good idea to utilize a programmable stat w/ a heat pump??? I do not remember the tech details as to why, but do seem to recall such posts.

Do you think a call to the co. that installed it would be in order?

 

plh_in

On the older model heat pumps, it was generally accepted by HVAC pros that you were better off leaving the heat pump thermostat setting on one temp for heating, one setting for cooling. But with today's newer models and programmable stats, there is nothing wrong with reasonable setbacks as long as thermostat does not call for aux heat(heat strips) in recovery mode. This is the key to savings. You only want the aux heat strips to engage when your thermostat is unable to maintain its setting. I am not a thermostat expert but I do know there are thermostats that can be programmed to accomodate setbacks and recovery in normal HP operation. You may want to contact your servicing dealer and get advice on this subject.

And again, I stand by my statement that it is not normal for continuous running of one's heat pump. Has your HP always behaved in this manner? When was last time your system was serviced? You may want to have a pro look at it.

My Opinion.

 

Ok. Here is the thing about a heat pump, They are sized for cooling.

Unless you live in a very mild climate sooner or later it will get colder. The colder it gets the longer the HP runs to keep up. This is because of two things. One is that as the temp drops the load on the house goes up, i.e. the house loses heat faster when it is colder outside. Number two is that as it gets colder outside the capacity of the heat pump goes down, meaning the colder it is outside the less heat there is for the heatpump to transfer into the house.

Sooner or later your heatpump is going to run all the time and this is normal. If it doesn't you either live in a place that doesn't get very cold, or you have a moisture problem during the summer.


The OP never stated what the temp is outside. This might give a better clue as to if there is a problem or not.

 

The outside temps are generally in the mid to low 30's. I think you might be right on, as the temp gets into the 40s, it seems like the unit will shut off more easily.

 

Shanks got it right. All the more reason to purchase a 2 stage heat pump or dont install one in the north quarter of the US.