New Digital Thermostat and Furnace won't stay on


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Old 01-06-13, 05:45 PM
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New Digital Thermostat and Furnace won't stay on

I just installed a new digital thermostat that I received for Christmas. It is a Honeywell Model # RTH221B and it replaced the classic Round Style Honeywell thermostat. I have it connected to a Lennox Gas Furnace. It has 4 wires connected, Y, G, R, and W and I connected them to Y, G, Rh, and W. I am able to get the furnace to turn on, but after it reaches the correct temperature and shuts off, it won't come back on even after the thermostat tells it too. After I reset the furnace by flipping the circuit, it comes back on and heats the house up until the thermostat switches off again, but then it reverts back to it's previous state. What could be causing this issue?
 

Last edited by aheisey; 01-06-13 at 08:16 PM.
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Old 01-06-13, 07:17 PM
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is there a jumper from Rh to R?
 
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Old 01-06-13, 07:55 PM
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Yes. It came with the jumper from Rh to Rc.
 
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Old 01-06-13, 08:12 PM
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Does the fireplace have a blower that the old thermostat controlled?
 

Last edited by hvactechfw; 01-06-13 at 08:57 PM.
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Old 01-06-13, 08:20 PM
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I corrected my post below. It is a furnace, not a fireplace. I don't see anything that looks like a model number, but I'm not sure where to look.
 
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Old 01-06-13, 08:42 PM
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OK. Thanks. Does the unit have power going to it? Does it have a low voltage fuse that is blown?
 
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Old 01-06-13, 08:46 PM
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By unit, do mean the thermostat or the Furnace? If the furnace, then yes, it is on its own dedicated circuit. For the thermostat, no. It just has the 4 wires. I checked, and its one of the older mercury style thermostats. I put the old one back on and it works fine so far. I doubt it has anything to do with a fuse? Do you think the thermostat is incompatible or bad?
 
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Old 01-06-13, 08:57 PM
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Your replacement thermostat is a very low end honeywell. It may very well be a bad unit if the old thermostat works fine.
 
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Old 01-06-13, 09:39 PM
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Ok. What would you recommend? And how much do you think it will cost?
 
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Old 01-06-13, 10:00 PM
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A "good" thermostat will cost you at least $50. Stick with a Honeywell. A better thermostat will cost you closer to $100. Around the $100 mark you could get a wifi thermostat for smart phone/internet access.
 
 

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