How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Douglas Your Own Question
Douglas, HVAC Technician
Category: HVAC
Satisfied Customers: 3089
Experience:  Manufacture Rep for Major Brand, Technical Trainer, NATE
Type Your HVAC Question Here...
Douglas is online now
A new question is answered every 9 seconds

I have a model 5200 thermostat regulating a heat pump. We

This answer was rated:

I have a model 5200 thermostat regulating a heat pump. We have frequent power outages and the thermostat will not HOLD a temperature. Everytime the power goes out and comes back on it reverts to the fatory setting. It has a battery which I assume is to hold the settings during a power failure. However, the battery only lasts about a month. Is this normal? How can I fix this problem?
Hi, I'm Douglas and I am here to help you resolve problems with your heating and cooling equipment.

That battery should last at least a year. It serves very little purpose but to keep the program and clock going. Are you using aklakine batteries (Duracell or Energizer)?

If you remove the thermostat from the wall, is there a wire on the C terminal? (If there is a C terminal).

Customer: replied 4 years ago.

I am using alkaline batteries. I am not where I can remove the unit from the wall. I suspect that the wiring is not right because the technician who installed it told me it did not need a battery. Please send me detailed instructions on how the wiring should be to insure that the battery holds the settings and does not run down the battery so quickly. I'll fix it myself.





what brand heat pump?
Customer: replied 4 years ago.
Customer: replied 4 years ago.

I repeat. The brand is Carrier. Waiting for a response.

Ok... regardless, when we are dealing with a power outage, its going to run soley on battery (not really run, but be powered).

What he's telling you is that he connected the common wire to C. This uses system power but again, when the power goes out, its battery.

Each installer uses his own colors, one would have to know what colors he used. R is just about always Red, Y is almost always Yellow. G is almost always Green, O is almost always Orange. Common (C), Emergency Heat (E, W1) Aux Heat (W2) can be whatever he chooses. Usually blue is common, White goes to W2 or E, black to E but there is no hard fast rule there.


Again your problem is batteries Does it show you a battery icon on the screen or does it say AC often?
Customer: replied 4 years ago.

It shows me a battery icon on the screen. This is a seasonal residence. Used occasionally. If I set the heat on HOLD and return after a month I find the battery icon with an X throught it and the the thermostat returned to the factory default, 68 F. In the winter this is bad because it runs my heating bill up while the house is unoccupied. There has most likely been a power failure while we are not there.

I see.

Let me ask you this...I'll explain in a bit.

Do you really want a programmable thermostat?

Does your seasonal home have internet?
I ask because this is not the thermostat I would suggest in a seasonal home. You would either want a very simple manual thermostat or one that you have wifi access to (this is all new technology that wasnt available only a year or two ago)

Wifi enabled thermostats are what most people use if the remote home has internet. If it doesnt, then we would rather use a basic mechanical. Any programmable is subject to resetting to the Energy Star program which in your case is not good.
Customer: replied 4 years ago.

My seasonal home has internet but that is not reliable either because of the frequent power failures in the Winter - ice and snow play havoc with the cable. Carrier tried to interest me in the WI-FI but I'm not sold on it for this application.

Are you sure that no programable thermostat is going to work under these conditions? Carrier says they have a thermostat that does not require a battery. How does that work? To my knowledge any electronic device that needs backup during a power failure requires a battery even if it is built-in.

No it will work, but in your case, if you lose power long enough, it will resort to the preprogrammed setting. Many thermostats dont require batteries, ofthen they have a capacitor or watch batter that holds the program for a short period of time. This is not going to be any better than a couple AA batteries in the one you have. For instance, my thermostat (not compatable with your system) has no battery, but it holds the program for about 3 hours, after that, it loses it.

Do you use the program when you are there? (wake, leave, return, sleep)

As far as wifi, If the inernet goes out when the power does at least you can then reset the thermostat from your smart phone or computer when the power is restored. You can also set alarms to notify you if the signal is lost or the system fails for some reason protecting from a potential freeze.

Customer: replied 4 years ago.

Thanks for your help.



Good luck
Douglas and other HVAC Specialists are ready to help you