Heat Pumps and Electric Heating - input line temperature

I just recently moved into a new apartment that does not seem to be able to keep a comfortable temperature w/o using aux heat. This is my first experience with a heat pump and I'm used to radiator heating, so I have been reading as much as possible to learn more about this type of heat but I have a few questions. From my reading some people say the output air at the vents should be around 90 deg while other say it should be about 20 degs higher than the input air temperature. Is the output air temperature dependent on the input air temperature, or should it remain relatively constant? For example, I do turn the thermastat down a little bit over night, and even more in the morning before I leave for work. When I get back from work I slowly turn it up incrementally so that the aux heat does not turn on. When I get back, the temperature of the apartment is probably around 55 degrees, but the air at the vents barely feels warm. When the temperature near the vent closest to the air handlger gets to about 62-65 degrees, the air from the vents feels about room temperature. Also the vents farther fromt he air handler definately feel cooler. Is this about normal or do I probably have a problem?
My other question is what temperature should the refrigerant input line be while the heat pump is on. Right now if I grab the line with my thumb and index finger, it gets uncomfortably hot but not close to burning my fingers. Should it be burning to the touch?

I am going to call for service no matter what, but I wanted to see if I definately have a cause tell the maintenance staff there is a problem.

Sorry for the long post but any help is appreciated.

-Mike

It does not sound like you have a problem. Because a heat pump is a basic refrigeration system, it has certain properties. You will have to trust me because to understand a heat pump you have to understand refrigeration. That said, you were well informed when told the air temp. would be 20 degrees warmer than room temp. unless the room temp is lower than the design temp. In other words, as the room temp. gets lower, the differential between supply and return temp. gets lower BECAUSE of the refrigeration process. Therefore you may only get, say, 65 degree air from your system when the room temp. is 55. This will cause very long run time to get back to your higher set point. I would suggest installing a thermostat to accomodate for the low setback. Your HVAC supplier/ dealer will be able to help. Regretably, I can not suggest a model because I do not subscribe to a large setback for a heatpump.

Thanks for the reply. I'm not going to use as large a setback over the next couple days and see what the output temp at the vents is. I have thought about getting a programmable thermostat, but I have to do more research first. I have to call service anyway because of no air flow out of a vent, so I guess I'll also ask them about a thermostat.

Again thanks,

Michael

ironhead1230

What is make, model, size, and age of your HP system.

What area of country do you live?

Like Thermo, I do not subscribe to your large setback in the day. I would not setback stat more than 4 degrees. I agree about looking into a programmable stat.

Depending on outdoor temp, you should be getting supply air temps of at least low 90s.

The refrigerant line to your air handler should be very warm to the touch.

Any idea at what outdoor temp your aux heat is being activated?

I have to question whether your refrigerant charge is correct and only an HVAC pro will be able to determine this.

Let us know what you find.

My Opinion.

i gave up on the setback idea a while ago. it takes too long to heat up and the compressor and fans run much longer when it does try and catch up. I figured the extra run time negated any savings from the set back. i now run my heat pump just like a ronco showtime rotisorie- i set it and forget it.

Its a good idea to set it and forget it.You can help yourself by making sure your air filter is clean.As far as the general operation of a heat pump goes,I will try to explain it as best I can....In the summer,your heat pump takes the heat from your house and rejects it to the outside through the refrigerant.In the winter time, that process is reversed.The heat from the outside is moved to inside your house.There is heat in the air down to -460 degrees.As the outside temperature goes down, the heat pump becomes less effective.Thats when your electric back up heat comes on.Thats also when your electric bills go up....Good luck.

everyone take note, ironhead says that he is living in an apartment, so there is really very little he can do on altering the system that was installed when he moved in. he messes anything up he will be responsable for the repairs to the system. he also claims that this is his first experiance with a heatpump, so he may not fully understand that they work way different from the radiant heating that he was used to before. ironhead, i didn't mean to put you in the third person, but you must know that you do not own that apartment, you rent it, i'm trying to keep you from getting yourself in trouble.
what thermofridge said is true except the recommendation of changing out the thermo unless it was your own home( i would do it if it was me, of course we have other tricks to the trade). what i would do if i was in your shoes, be home one day and ask for the maintenance supervisor, him in person, to come to the apt.and make sure that the entire system is performing properly, get him to explain how the whole system works to your understanding, heck take notes, won't hurt when you get your own home, thats when you really start having fun. let us know how it goes.
barry

ps, i am an a area apartment supervisor.

Again thanks for the replies. From some suggestions I went out and bought a thermometer with an outside lead. Over the last couple days I have been watching the temperature at the input vent and the temperature at the closest output vent. I do not think I have a temperature problem with the heat pump. I definately was not used to the temperature of the air a heat pump outputs. I was used to other types of heating. I was also setting the temperature at the thermostat too low and that was reflected in the temperature of the output air. Over the past couple of days I have set the temperature higher and that has resulted in a noticible incerase in temperature of the output air. The output temperature has been right around 20 degrees higher than the input temperature. The thermometer is cheap so I know it is not 100% accurate but I have seen output temperatures as high as 92 degrees with just the heat pump and 108 degrees with auxillary heat.

I definately would like to get a new thermostat because my current one sometimes seems to turn on the auxillary heat when it shouldn't. I am going to ask service if they would install a new programmable thermostat if I paid for it. I have also found some minor and major drafts around windows, doors, outlets that I will be getting fixed. I am also going to seal the windows and patio doors with plastic sheeting.

I only have one other problem with the heating system. The vent in my living room is only outputting a very small amount of air. Service came out once and said to close some of the other vents to equalize the airflow in the apartment. This does not seem to be acceptable. I am going to call again about this problem. The one area that I do not think I can fix is that I am on the ground floor and I think I am losing quite a bit of heat through the floor.

Thanks for the help

-Mike