Honeywell RTH221 theromstat problem

[13.2kv]

Hi guys, first post but long time lurker. I am in the process of installing a Modine hotdawg 45k btu unit, it's my job to wire it up and hook up the thermostat before the propane company comes and connects the gas.

I wired it up today and when I went to hook up the tstat it would display the time and temp like normal when I was holding it in my hand but when i went and plugged the tstat into the backing plate that connects the tstat to the unit and the tstat shuts off, then comes back on a couple seconds later in diagnostic mode then shuts off again permanently.

I looked at my wiring diagram and it showed:

G-call for fan
W-call for heat
R- (blank)
C- (blank

I think red is tstat 24v source so I am assuming I need a different tstat cable, correct? I don't know what C is for though.

Thanks in advance.

 

[mark11]

Red is power, correct.

 

[brihvac]

Red- 24V
White- Heat
Green- fan
C -common
If you hook up R&C to your heater and stat; you do not need batteries in the stat.

 

[13.2kv]

Ok great, thanks!