Heat Pump question

[Fisher of Men]

Hey guys. Up until the summer when we sold our house, we've had gas furnace heating in our home. With the recent lows in 30's and 40's, I decided to turn our heat on the other day. The duplex we are currently living in has a heat pump. About a month ago, I installed a programmable thermostat (without the land-lord's permission thinking I'll install the old one when we leave :-[) by the book (wire for wire). I programmed it for heat the other night (before the temps dropped). When the temp reached 69 (set at 70), the outside unit kicked on and began running, but no air came from the vents. I let it run for a few minutes and then turned the fan setting to "on". I could then smell and feel heat coming from the vents. Not being that cold (and having to get to work) I just turned it off.

My question is this. Is the outside unit supposed to come on and run for awhile before the inside fan starts blowing? Obviously, now renting, I would need to call the landlord before getting it repaired. If this is the case, I want to make sure I didn't mess something up with the new thermostat. I'm pretty mechanically inclined, but HVAC is a weakness of mine. Any help would be appreciated. :-?

-Fisher

[FD.]

There should be a temperature sensor in your air handler.  In heat pump mode your condensor unit (outside) will run for a few minutes before the temp rises enough for the evaporator fan (inside) kicks on and it will run for a few minutes after the outside kicks off.  If you smell something burning, that means your heat strips have kicked in and is burning the dust off and the fan should follow shortly.

[Fisher of Men]

Thanks Fishindaddy. I'm familiar with the burning dust smell as I have a heat pump unit in my classroom at school. We just got another front and the temps are supposed to drop back to lower 40's/mid 30's the next couple of nights. I'll let it run for awhile longer and see if the inside fan kicks on.

My plan (as used to be with the gas furnace) was to keep the unit around 70 in the evening and program the temp. down to 65 at night, then back up to 70 (or hold at 65, if my wife works) in the daytime.

A tip on one website said not to do this because the auxillary heat would run to catch up those 5 degrees in the morning. Can someone suggest times and settings for my unit (for best efficiency)? We get up around 6:30, I go to work around 7:30 (my wife substitute teaches and is gone some of the time). We get home around 4:00 and go to bed around 10:00.  Of course on the weekends we are home most of the time except for church on Sundays (weekends we travel I always just manually turned it down to "hold").

[Glenn]

I know some thermostats work only with 2-stage furnaces (I think that's the terminology).  Might want to check to be sure you're paired correctly first.

[Fisher of Men]

I know some thermostats work only with 2-stage furnaces (I think that's the terminology). Might want to check to be sure you're paired correctly first.

I ran it again this morning for about twenty minutes before I left. . . nothing.  I did, however feel cold air coming OUT of the return air vent.  Glenn, I'll check the new thermostat package when I get home.  At this point, I am prepared to put the old one back on and see if it works.  We are only planning on being here until the beginning of the new year anyway.  I'm just trying to get this all worked out before the really cold stuff hits here (you know, Northern guys, like 32 degrees).  

[jax]

I played with the programming this summer with our cooling bill. We leave at 8 am and get home around 5 pm. I set the thermostat to 76 at 4pm and to 80 at 9am. I let the house raise 4 degrees during the day. I did NOT help our cooling bill. I tried it with the heat for the first time last winter taking from 70 to 74 on the same time frame. It DID not help our heating bill. This was the first year I played around with it. I will not be doing that again.

I agree with the theory that when you change the tempature you are changing the temp of EVERYTHING in your house. So when you bring the temp back to where you want it you have to change the temp of EVERYTHING in your house again. Walls and flooring being the hardest temps to change and the ones the that need to change the most.

Heat pumps do not put out hot air. They put our warm air. Therefore it takes longer to warm up and longer to feel warm. If I there is too much of a temp change then the aux will kick in. There goes the effeciency of your heat pump because it just kicked into electric heat.

I'm going to leave the thermost alone this year to compare. I'm pretty sure my heating bill stayed the same at best but we were alot colder waiting on everything to heat up. It may have saved us a few pennies but it was definately not worth it.

I'm not a heating and expert guy though. My house is well insulated. Others may have had better results.

[.ghoti.]

The old rule of thumb for temperature rollback was one degree per hour. With heat pumps and aux electric heating that goes out the window.

[mattm]

Fisher,

You should adjust your unit if you are going to be gone long periods of time.  Like you are for work.  Don't worry about it though if you are going out to run errands for a couple of hours.  Never adjust more than 5 degrees.  Anything more than that and the unit has to work too hard to adjust the temps back up so you will lose any saving that you had at the lower temps.

If your unit was blowing air everything is most likely ok.  If you are used to gas furnaces the air is going to seem cool until you get used to it.  However, a heat pump will not dry everyting out like gas.  Your home will be more humid and the winter dry skin should lessen.  On extremly cold days when the highs are like 32 or so the unit should be ran in emergency heat mode.  This is probably the same thing as the aux. heat you were mentioning.  It is probably also worth a call to the manf. to see what  temp they suggest running the unit in em. heat mode.

Let me know if you have any other questions.

[bigdog]

There should be a temperature sensor in your air handler. In heat pump mode your condensor unit (outside) will run for a few minutes before the temp rises enough for the evaporator fan (inside) kicks on and it will run for a few minutes after the outside kicks off. If you smell something burning, that means your heat strips have kicked in and is burning the dust off and the fan should follow shortly.

heat pumps get heat from the out side unit. not inside airhandlers whole differant units. let your heat pump run for a while becouse the heat is genrated from the condenser pump. it has to get hot enough to open the reversing valuve to give you heat. amd make sure you have a heat pump stat.or it wont work wright.

[Fisher of Men]

Thanks for the input guys.  I got home from work, removed the front panel from the new thermostat to remove the hold and noticed a selector switch on the back of the circuit board.  I switched it to "HP", read up a little in the manual to find that my thermostat only works with single stage systems (come to think of it there was no switch or little blue light on the old thermostat), so I put the front panel back on.  I switched it to "heat" and both units came on and within five minutes warm air began to flow.  

So. . . I'm assuming that I have a "single-stage" unit that doesn't have electric/auxillary heat.  What am I supposed to do in "cold" weather (below 32 degrees), freeze to death?

Should I buy a portable space heater or two?

[mattm]

If my understanding about the emergency heat is correct, and please understand that i'm assuming that what you are calling aux. heat is the same thing, than you will not necessarily freeze.  The emergency heat if i'm correct is ran in that mode to protect the outside unit more than it is to provide more warmth.    It will warm a 45 degree room to 70 faster, but once it gets there 70 is 70.  I think manf. recommend em. heat so the outside unit doesn't freeze up.  Very few of my homewoners know to do this, and I don't ever remember someone telling me their unit frooze.

[clipper]

You were correct to switch to the "HP" setting on the tstat subbase.  The fan on a heat pump should come on as soon as the outdoor unit starts which is different from gas or straight electric resistant heat.

Unless you live in south Florida or a similar climate you will need auxilliary electric resistance (strip) heat to supplement the heat pump in cold weather.  If you bought a tstat for a heat pump it should have the capability to bring on that resistance heat when the room temp drops 1.5 - 2.0 degrees below setpoint.  You can usually tell this because the temperature of the discharge air will be considerably warmer than what your heat pump puts out.  Some of these units also have an outdoor thermostat to keep you from running the resistance heat unless it is cold weather and really needed.  The purpose of this is to keep your electric bill from being too high as a result of heating with the resistance heat.  

If your tstat had a terminal marked W or W1 it is probably for the resistance heat.  The instructions that came with the stat should explain this.  Switching wire to wire from one brand of tstat to another might not work unless  you are lucky.  You need to read the instructions carefully to make sure you got everything in the right place.  Send me a PM if you need more help.

[Fisher of Men]

Well, when I got up this morning, the house was at 70 and the heat was running (just as programmed to do). It's hard to get used to having lukewarm air coming out of the vents.  It was always nice to feel that furnace kick in and give you a warm burst.  The temp on the front porch read 36 degrees.  I will still check the connections, clipper.  Thanks again for everyone's help.  

-Fisher