Heat Pumps and Electric Home Heating - Replacing Honeywell t86 with RTH7500D

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DFabry
05-08-08, 08:48 AM
I am replacing an original Honeywell thermostat with a Honeywell 7-day digital thermostat. The wiring diagram has me a little confused - on the original, the wires are attached to the B, R, W, Y and G connectors, and the new ones don't really allow for B and W to both be used. The air conditioning unit is a 2002 Bard, and there is a heat element hooked up for (rare) use as well. Can anyone help with the correct wiring?

Thanks much

Jay11J
05-08-08, 12:43 PM
Is your unit a heat pump, or just A/C with electric heat for cold days?

Model # on the unit?
DFabry
05-09-08, 12:05 PM
Is your unit a heat pump, or just A/C with electric heat for cold days?

Model # on the unit?
It is A/C with electric heat for cold days

Thanks very much for any assistance you can proivide

DFabry
05-09-08, 12:08 PM
I will need to get up on the roof - it is a 2002 2-ton Bard air conditioner unit, not sure of the model number, but I will find out. back in Rochester, Minnesota this weekend to close on our old house, so I will check when I return to Fl on Sunday evening.
Jay11J
05-09-08, 04:07 PM
Only thing I can think of is B is maybe Common, when you do get up on the roof, take a look to see where that wire go to in the unit.

W-Heat
G-Fan
R-Power
Y-Cooling

B could be common, (C is common in most setup now days)

Where did you move to? Couldn't take our REAL winter last winter? :-)
Ed Imeduc
05-11-08, 03:55 PM
Like Jay said B can be common there. Dont know that Bard unit. But Coleman ,Trane on 2 units and York all used a B on some of their units
DFabry
05-12-08, 09:24 AM
Thank you both- I will try to climb up on the roof tonight, now that I am back in Miami Beach from Rochester, MN, where it was a cool 40-something at night. I do not think that we will be needing heat anytime soon down here - today's high is forecast to be the mid-90s. Is there any HARM in trying the suggested configuration below, or should I verify the model number prior to hooking up?
Jay11J
05-12-08, 11:36 AM
Too bad the weather wasn't nice over the weekend here.. A transfer down to Mayo for you?

I would wait till we know for sure what you got, I'd hate to wire C on something else, and fry up something.
DFabry
05-13-08, 11:28 AM
Ok - will try - nope, left the Mayo system and joined the University of Miami Medical Center.