Question about Honeywell Programmable Thermostat Heater

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Batteries died on my honeywell RTH230B replaced but furnace won't

My batteries died on my honeywell RTH230B and I have replaced them,.I can't get the furnace to turn back on.. The fan if set to on will kick on but the furnace unit does not.. Worked perfect until the batteries died overnight.

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  • boomboomvond Feb 02, 2010

    Ok, it was fixed when we put fresh (right out of the package) batteries in the thermostat. We did turn the furnace to the Off position before removing the old batteries and I held the Mode button while I put the new batteries in. I don't know if that did anything but reprogramming it didn't seem to matter until I put the totally new batteries in. Note that there was a bit of a delay (2-3 mins) until the furnace received the signal. I wish we'd have thought of this before calling the furnace guy for $90 worth of advice (his: Buy a new thermostat). Glad we tried brand new spanking batteries before doing that.

  • chedav
    chedav Feb 06, 2013

    Thanks boomboomvond your post saved the night, I don't know if the thermostat is the same model, but we were in for a cold night last night until I read your post and put in the new batteries with the furnace off and turned it on after installing the new batteries, waalaa the furnace kicked on!

  • beckiyw206
    beckiyw206 Feb 07, 2014

    Thank you also boomboomvond. After reading your post I went and got newer batteries, changed them with the mode button down. It actually worked. One little glich, when the furnace wouldn't start up the first time after changing the batteries we took the furnace cover off to look inside. Couldn't find anything so tried the new batteries. The furnace wouldn't turn on with the new batteries,but than realized there is a safety feature where the furnace will not turn on with the furnace cover off. Once we put it back on we were back on we were back in service!



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You will have to reprogram it according to the operating manual.
The manual is available on

Posted on Feb 02, 2010


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