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 gotoman for ac Your Own Question
gotoman for ac
gotoman for ac, HVAC Technician
Category: HVAC
Satisfied Customers: 5165
Experience:  51 years of experience install design and repair of all makes and models of AC
Type Your HVAC Question Here...
gotoman for ac is online now
A new question is answered every 9 seconds

Hello, I have a similar question. I have a Bryant 383 furnace

This answer was rated:

I have a similar question. I have a Bryant 383 furnace and will be installing a Honeywell RTH8580WF thermostat. The old thermostat did not have a C wire run, so I'm going to run a new 18-5 bundle. At the furnace, do I just replace the existing wires with the new ones and add the 5th wire to the C terminal? And then use the wire from the C terminal on the furnace to the C terminal on the thermostat? I should also note that I have a Bryant central air unit and Aprilaire humidifier installed, not by me buy previous homeowner.
Russ here..Yes use C wire on furnace to C on thermostat. All Wifi has to be hard wired. Russ
Customer: replied 3 years ago.
My question concerns when I run the new wire bundle is it as simple as just replacing the existing 4 wires and connecting the 5th wire to the C (actually it says Com on the board) terminal on the furnace? There are already 2 wires connected to the Com terminal, one is part of a red and white bundle (probably A/C unit) and the other is a red and white bundle which is related to the humidifier. Is there a limit to the number of wires connected to the Com terminal?
No limit to number of wires on C or Com terminal. You are correct just a simple run and connect to C. Russ
Customer: replied 3 years ago.
Ok, based on the information I have provided, this should be as simple as shutting the power off and hooking up the new wires. I just want to make sure there isn't something I'm overlooking that could cause a blown fuse or fried circuit board. Is this correct?
Yes this is correct. You ask the right questions. Just connect wire per wire and you will be fine. There is a fuse on board that will blow if you connect wrong wire but I think you know what you are doing. Russ
gotoman for ac and other HVAC Specialists are ready to help you