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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 922
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I am trying to go from an ASYSTAT655 to a Honeywell RTH6350

Customer Question

I am trying to go from an ASYSTAT655 to a Honeywell RTH6350 Thermostat on my heat pump. The ASYSTAT655 had
R, T, O, G, Y, X2, B, and W wires hooked up. The Honeywell has places to hook up RC, R (jumpered with RC), Y, Not Used, O/B, G, Aux/E, and L. I have hooked up the
R to R,
Y to Y,
O to O/B,
G to G,
W and X2 to Aux/E.
The B and T wires are not hooked up.
The thermostat is not working. What do I need to change to get it working?
Submitted: 2 years ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 2 years ago.
Hi, I'm Brian and I'm here to help! You have the wiring exactly correct! The B and the T wires should be wrapped with electrical tape or the ends insulated in some other way and tucked back in the wall behind the thermostat. The B wire is 24 volt common from the low voltage transformer. If it touched any other wire while the low voltage was powered up it's possible you may have inadvertently blown a low voltage fuse in your unit or air handler. That is something you should check. However, that thermostat should power up with batteries alone so make sure the batteries are fresh, installed correctly and are making good contact with the battery contacts on the thermostat. If the thermostat will not power up with batteries alone, even without anything connected to it, the thermostat may be bad out of the box and you should return it for a replacement. Give that a try and let me know how it turns out. If you need further help or have related questions, please reply back. Otherwise, if I have helped you resolve your issue, please remember to rate positively before you leave tonight. Bonuses are always appreciated! Thanks, -Brian
Customer: replied 2 years ago.

Thank you for your time. I fixed the problem. I forgot to go in and set the stat to run in heat pump mode.

Expert:  Brian HVAC Guy replied 2 years ago.
Thanks for the reply letting me know. I misunderstood that your thermostat wasn't working and took it as not powering up at all. I'm glad you were able to figure it out yourself. Thanks for allowing me the opportunity to help and thanks for using Just Answer! Best regards,Brian