Need wiring help (pics inside)

Old 07-04-14, 10:37 AM
Thread Starter
Join Date: Apr 2014
Posts: 2
Received 0 Votes on 0 Posts
Need wiring help (pics inside)

Hi, I've got an old Hunter 44550 thermostat that I'd like to replace with a Honeywell RTH6450 - but the terminals and wires don't match up exactly...

On the old unit I had the following wire/terminal connections: W > W; R > RC w/jumper to RH; G > G; Y > Y/Y1; and O > O/B; with blue, black, and brown wires taped off at the ends.

On the new unit I'm able to match most of the wires however, the Honeywell stat is lacking a dedicated O/B terminal and instead appears ta have some alternate wiring terminal labels underneath the terminal bank (in addition to what I'd imagine is the primary labeling on top of the bank).

Sort of confused where to put the O/B wire - if it's to go in the alternate terminal - and where to then put the white wire (in the W2 slot?) ...

Any suggestions? Pics of the old model are below, followed by the new Honeywell

Name:  photo.jpg
Views: 2023
Size:  43.3 KBName:  photo 2.jpg
Views: 475
Size:  27.2 KB

Old 07-04-14, 10:44 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
Looks like you have correctly wired your new stat but you must also configure the new stat for heat pump with Aux heat. (Function 1 = 5)

The O/B terminal must also be configured to be O or B.
Function 2 = 0 for almost all heat pumps except Rheem, Ruud, and Weatherking.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: