[speedster1]

I have a Honeywell RTH9580WF that I used in my old home and brought with me to my new home. The new house is gas forced air and has a basic Honeywell 4-wire thermostat. Instead of running new 5-wire it would be much simpler to pull from a nearby 24V doorbell transformer (about 3 feet away).

Can I just run 2 wires from my doorbell? Hook one into the "C" slot and put the other on "RH"?

 

[supers05]

The doorbell transformer isn't likely to be big enough. This is inadvisable, however, as long as the 24v to the doorbell isn't grounded, then it may work. (if it's grounded, then I'd highly not recommend this.)

In many jurisdictions, this would constitute "multiple power sources". It may not be legal, and/or you'll require a notice on all devices that it has multiple power sources. I'm not an electrician, so I'm not good with those codes.

Cheers!

 

[beenthere]

I have a Honeywell RTH9580WF that I used in my old home and brought with me to my new home. The new house is gas forced air and has a basic Honeywell 4-wire thermostat. Instead of running new 5-wire it would be much simpler to pull from a nearby 24V doorbell transformer (about 3 feet away).

Can I just run 2 wires from my doorbell? Hook one into the "C" slot and put the other on "RH"?

No. The RH must be powered by the same transformer that furnace/air handler uses.

Glad you got the new owners of your old home to agree to let you take the thermostat with you.

 

[speedster1]

OK thanks for all the help. I'll just run new 5 wire. Will be a PITA but oh well.

As for the thermostat, I uninstalled it and put the old Lux back in place before I ever put the home on the market. The new owners never even knew the Honeywell existed

Sent from my Nexus 6P using Tapatalk

 

[beenthere]

Might want to run a 8 wire. So that down the road, if you get a new furnace, and its 2 stage, the thermostat can control the staging.

 

[supers05]

The extra wires will also help if you get a (de) humidifier and want the stat to control humidity

Cheers!