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I just changed batteries in 7 day Honeywell thermostat and…

Customer Question
I just changed batteries...

I just changed batteries in 7 day Honeywell thermostat and can not get the heater to turn on.

Contractor's Assistant: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?

Thermostat worked fine until batteries died.

Contractor's Assistant: Do you plan on doing the work yourself?

If possible.

Contractor's Assistant: Anything else we should know to help you best?

I only have three buttons besides the heat or air buttons that say set, run and hold. what do I do to get this ting to work.

Submitted: 8 months ago.Category: HVAC
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Answered in 2 minutes by:
12/29/2017
HVAC Technician: airheatman, HVAC Technician replied 8 months ago
airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 9,536
Experience: Furnace, A/C and heat pump specialist.
Verified

Try setting to Heat then hold and then set temp above room temp.If heat does not come on issue may be with furnace rather than thermostat

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Customer reply replied 8 months ago
I just changed batteries in thermostat and had to reprogram daily settings. do I need to have thermostat on todays setting?
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

If you select heat Hold and set temp above room temp day should not matter

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Customer reply replied 8 months ago
ok setting room temp higher and hold did nothing.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

Issue is probably with furnace.Remove R and W wires on thermostat and touch the wires together and see if furnace comes on

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Customer reply replied 8 months ago
Forget the phone call and give me some answer other than something may be wrong with heater. It worked just fine until I changed the batteries in thermostat.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

If you want help please follow my instructions.

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Customer reply replied 8 months ago
I touched the R and W wires together with no response.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

OK that proves as I was saying that thermostat is NOT the issue. You just bypassed the thermostat.Can you look inside the burner compartment on label on side panel and get me the model on your furnace? Then look in blower compartment and see if there is an error light blinking that will guide us in determining what is failing with the furnace.)Not if no peep hole and you have to remove blower panel to see control board, it will be necessary to hold door switch in to have power to board)

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Customer reply replied 8 months ago
it's a Rheem Heater. I couldn't find a model #. The pilot light is lit if that's any help.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

Model will be on a label in burner compartment on side panel

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HVAC Technician: airheatman, HVAC Technician replied 8 months ago
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Customer reply replied 8 months ago
model # is hard to see. I think it's 3204-80JD
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

Should begin with letter R

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Customer reply replied 8 months ago
No letter R. It is as I described.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

OK if nothing with letter R this thing has to be at least 40 to 45 years old. Does that seem correct?

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Customer reply replied 8 months ago
house was built in 74. It's possible.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

Wow that is an oldie.I will not be able to find a manual on that one.

Let me ask you this.Do you have a volt meter to do some troubleshooting?

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Customer reply replied 8 months ago
I'm not that technically friendly.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

What we need to do is see if we have voltage between the R and C terminals on the transformer on the inside left of the furnace.

That R at thermostat is 24v hot. Connecting it to W should send the 24v hot back to the gas valve if we have power from transformer.

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HVAC Technician: airheatman, HVAC Technician replied 8 months ago

I understand that it doesn't make sense all you did was change batteries if furnace was working before, but if you connected R and W wires and furnace does not come on we have a problem in furnace.You may want to just call in a service company if you are not able to troubleshoot and don't have meters.

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Customer reply replied 8 months ago
I shorted the connection between R and C and produced a electrical spark.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

Yes R and C will create a dead short that is 24v hot and 24v common

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HVAC Technician: airheatman, HVAC Technician replied 8 months ago

You cant short those two.That is where we wanted to put our meter leads,

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Customer reply replied 8 months ago
ok How do I connect R to W
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

At thermostat you already did right?

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HVAC Technician: airheatman, HVAC Technician replied 8 months ago

OK do you see an R and a W on that transformer in furnace? If so use a pair of needle nose pliers and touch the tips to R and W. Hopefully you did not fry thermostat earlier when you shorted R and C

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Customer reply replied 8 months ago
R and W connected with no result. Transformer still makes sparks.
HVAC Technician: airheatman, HVAC Technician replied 8 months ago

OK we have to have a limit or something in the furnace open.Coincidental that you were just changing thermostat batteries but touching R and W should bring on gas valve. Thermostat and external wiring are totally out of the picture.

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