My wife and I are renting a house. This house is a split level and has a heat pump. From what I can tell, it is a Bryant, or at least that is the name on the thermostat. The thermostat has a green light marked Aux Heat and a red light marked Emer. Heat. When the heat pump comes on, both of those lights come on. I read somewhere, that it isn't normal for both of those lights to come on and that the system should be checked out by a professional. Is there something I can try to fix it?

Thanks,

Chris

 

Well, Chris, it all depends if both of those lights are staying on or if one is going off.

When you first turn on the heat pump or it has been on and you turn it up then the aux. (inside electric heat strips should come on to help boost the on-demand heat, but the aux. heat should only stay on for a few minutes.

Normally the green light is for the inside aux. heat strips (when they are temporarily on) when the heat pump is on.

The red light is for if the heat pump breaks down and you put the thermostat in emergency heat then only the inside electric heat strips are on.

If both lights for the electric heat strips are on and staying on then there is something SERIOUSLY wrong and you are going to have a VERY HIGH electric bill, like you are experiencing.

Open up the inside close where the air handler is and you should see 2 freon tubes, one bigger possible with a black wrap around it. Lightly wrap your fingers around it and you should feel it slightly vibrating, this is how you know the heat pump outside is running. Also, it should be warm, if neither the heat pump is on defrost/thaw cycle or not working correctly.

It's quite possible the defrost board is bad.

 

Chris, I moved your post here as the thermostat (stat) is most likely at fault here.

First, understand the system. Heat pump outdoor unit in a/c mode removes heat from the inside and displaces it outdoors. This is the most efficient mode. In heating mode the unit (tries) removes heat from the out door and sends it inside.

I heating mode the heat pump occasionally needs a little help. The first place it needs help is in defrost. When the outdoor coil gets too cold a defrost is started. The outdoor unit switches to a/c which heats the outdoor coil and melt frost/ice.

During defrost the electric heat is turned on to keep heating the house, while the outdoor unit is actually in cooling. You don't see the Aux heat light on because the outdoor unit is turning the electric heat on, not the stat.

Electric heat is a resistance heater in the indoor air handler. The same exact component is both Aux heat and Emergency heat. If the heat pump is set at 68 degrees and the temp drops, the heat pump starts to bring the temp back to 68. If you decide that you want 70 degrees or it is taking too long to reach the temp (or the temp keeps dropping) the Aux heat will come on - the stat does this.

Emergency heat is used if the outdoor unit is dead for whatever reason and you place the stat in Em Heat. At this point the stat will only energize the fan and electric heat to heat the home.

The stat is the "brains" of the whole operation. The stat is relay a collection of switches (relays) that turns things on and off. There is a switch for the compressor, reversing valve, fan, aux heat, and em heat.

Normal operation in heat, is that the stat energizes the compressor and fan when the temp drops below set point 1 or 2 degrees. If the temps keeps dropping, the set point is raised, and/or the amount of time to get to temp is too long the Aux heat is energized and you will see the green light.

The fact that you are seeing both Aux and Em Heat lights points directly to the stat. As mentioned before, verify that the outdoor unit is on line. The large insulated line should be very warm to hot. If it is, then the stat is closing 3 switches (relays) on a call for heat. Compressor, Aux heat, and Em Heat. Change the stat.

 

I understand what you are saying. I will have to get up in the attic and look at the system a little closer, to find out where those parts are. Last I checked, it looked like the circuit boards were not accessable unless the sheet metal was cut. I could be wrong though. I will check it out and post my findings on here.

 

Just go to the unit outside, and feel the lines.. No need to cut anything.

 

If I need to get a new t-stat, what would be a good one to get? I was thinking about getting just a plain old non-programmable t-stat. We usually keep the temp at one setting.

 

You mentioned in your first post that you and your wife are renting the house. If that's the case, you shouldn't be altering the HVAC system yourself, and instead you should call the landlord and have him send out a tech to troubleshoot your system.

 

I went out to Home Depot and bought a Honeywell RTH3100C thermostat. I hooked up all of my wires and labeled them the way they came off the old stat. I tested the new stat and the heat comes on. When I moved the switch to the "Cool" selector, blower doesn't come on in the air handler and no air blows from the vents. I understand that the thermostat has a 5 min. delay to protect the compressor. I checked it about 15 minutes later and the air still didn't come on. The strange thing is that the blower comes on during the "Heat" setting.

 

The old t-stat is a T841A1639.

 

Make sure the "G" wire is hooked up.

Just to double check, here how it should of been.

Old-----New
E--------E
W2----Aux
Y1-------Y
G--------G
O--------O
L--------L
R--------R
X--------C

Then Advance system set up.

6-3
8-3

 

I will check when I get home. The only thing I see different is in my advanced settings, I chose 6-9 and 8-9, because our house is total electric. I will change those settings to see if that makes a difference.

 

The advance setting is not going to do anything for the blower.

I like setting them at 3 for better comfort, where 9 is way too short, and cycles often! The t-stat don't know if it's gas or electric.


Does the fan work when you switch the fan switch to "ON"?

 

Haven't tried that yet. I do notice that when I flip the switch to the cool side, the fan outside on the heat pump runs, which indicates that I have the red and green wires hooked up properly. I will check it out a little more tomorrow. I did read on another forum that someone had the same problem and the same t-stat as mine and when the Common wire was removed, the A/C started working. The installation manual does state that if I use batteries in the t-stat, not to hook up the Common wire. I do have batteries in my t-stat. Should I remove the batteries? Does the Common wire supply the necessary power to the t-stat for the temp. to display? Just a thought.

 

When you ran the HP, did the indoor fan run?

Common wire is run the t-stat with out battery. I would take the battery out. But check the G wir efirst.

 

When I run it in heat mode, I can hear the blower running. When I switch it to cool mode, I don't hear he blower running, nor do I feel air coming out of the vents.

 

You tried the fan switch ON?

At the t-stat, touch R and G wire together fan should come on. if it don't then go to the air handler and jumper R and G. let us know what happens.

 

I have solved this problem. I took the batteries out and when I turned it to Cool, I heard the A/C come on as it should. When the batteries were installed, only the heat would come on but no A/C. Now all of it works as it should. Thanks for all of your help. Next, I will be posting a new topic about our heat pump and a split level home. The Heat Pump is a Payne PH13NR042-C. The full model number is PH13NR042000ACAA.

Should I post as a new post?

 

Yes, post the new question in a new thread. Go to heat pump forum and add your new question.