Daily Power loss to Thermostat

[harakiro]

Hi Everyone-

We've recently purchased a home and have ran into some interesting issues with the HVAC that I was hoping to gain some insight to.

Our home has two systems one for upstairs one for down. Both units are on the roof and are "combined" units. (a/c and furnace). The make of these are Trane.

The thermostat wires available are (Green (G), Blue(C), Red(Rc/R), White(W1), Yellow(Y1).

We recently started having an issue where the upstairs thermostat stops receiving power pretty much daily. At about 5pm the volts to the R wire go from 26v to 1.2v. Then at 11am the following day it comes back. I've been monitoring this for 3 days now and it has been consistent each day.

I don't believe there is any kind of timer, nor know why there would be?

Thoughts?

Thanks in advance

Jesse

[Chris_Worthington]

Thread relocated to AOP

[malibustevens]

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[BaldLoonie]

Some brands will drop 24v to the stat with an overheat situation. Usually only lasts a few minutes unless a weak limit sticks open for hours. Now, Trane at least in gas furnaces doesn't do that. Likely their packs don't either so probably doesn't apply here. Seems funny that it happens same time every day though.

[jpsmith1cm]

malibustevens

This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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[vstech]

often, there is a overflow switch that is filling with condensate and shutting off the thermostat power. have a service company investigate why the problem is happening.

[Brent Ridley]

Do a simple check. Make sure the furnace isn't connected to a switch that is somehow getting turned off everyday (like a closet light or attic light switch). If you determined that is not the issue, call a local contractor and let them come out and take a look.

[harakiro]

Thanks everyone for your replies. I'm working on getting a tech out and hopefully get the mystery solved!

[TwincamDave]

Do you have "energy management"in your area from your local power company?Sounds like they are cycling you off during peak times to save power.

[beshvac]

often, there is a overflow switch that is filling with condensate and shutting off the thermostat power. have a service company investigate why the problem is happening.

Had this same problem....2 stage unit would run in high speed a couple of minutes...then power would be lost...condensate pump would pump restoring power...unit would come back on as normal. Other than the Tstat going blank for a minute everything was fine.