How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Brian HVAC Guy Your Own Question
Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 925
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
Type Your HVAC Question Here...
Brian HVAC Guy is online now
A new question is answered every 9 seconds

I'm ***** *****. I have a Honeywell model RTH6580WF. I' m

Customer Question

Hi, I'm ***** *****. I have a Honeywell model RTH6580WF.
JA: Thanks. Can you give me any more details about your issue?
Customer: I' m wiring up the thermostat. I was able to trace all the wiring from the control box in the attic. All of them lined up except the orange wire: there is on O slot on the control box, but no O slot on the thermostat
JA: OK got it. Last thing — HVAC Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 1 year ago.

Hi Joe, I'm Brian and I'm here to help!

It sounds like you have a heat pump and this is a very common question. The O terminal and Orange wire is for your heat pump's reversing valve to switch it into cool mode when the thermostat is set for cooling. The reversing valve fails to heat mode so it must be energized in cooling. The Honeywell RTH6580 thermostat should have two rows of designators for the terminals. One row should be for 'Conventional' wiring and the other row should be labeled 'Heat Pump'. You should be using the Heat Pump designators. The terminal the orange wire should connect to will be marked O/B in the heat pump designator. The thermostat is preprogrammed to operate that terminal to energize the terminal while in cooling. It can be changed for a Rheem heat pump to energize in the heating mode but unless you have a Rheem heat pump outdoor unit, there is no need to change the operation of the terminal.

Once the thermostat is wired and powered up, you need to go into installer setup and tell the thermostat you have a heat pump system either with or without emergency backup heat (whichever is your case). If you had wire(s) connected to E or Aux or W2 on your old thermostat, then you should choose 'Heat pump WITH auxiliary heat' for the installer setup system type.

Let me know how that works and if I can help further.



Customer: replied 1 year ago.
That will work.....thanks!
Expert:  Brian HVAC Guy replied 1 year ago.

You're very welcome Joe! Let me know if I can help further. Please don't forget to rate your service with me, 3 stars or higher please! Thanks for allowing me to help today and thanks for using Just Answer!