Thermostat internal wiring?

[Paperman]

Does a thermostat jump the Y and G together when in the cool position? I assume it does not do this in the heat position. I ask as working on a Rheem rooftop unit on my building today I had to look over the wiring diagram and cannot find how the room blower relay in energized in the cool position. Older RRGG unit.

 

[Stuff]

Most thermostats jump both Y and G to R for cooling. Some thermostats have a setting or switch for gas or electric heat. When set to electric heat they jump W and G to R for a heat call. When set to gas only W is connected to R.

I think that electric heat switch doesn't apply to you as the diagram shows FCC which looks like a fan and limit switch. It turns on the blower when the temp gets high enough. Also cuts power to the gas valve if over temp.

 

[LS6 Tommy]

That unit uses a single speed indoor blower motor, not a multi speed blower motor like a residential unit. There is no need to tie "Y" & "G" at the thermostat. The thermostat energizes the blower relay on a call for cooling, closing the blower relay Normally Open contacts (B2). On a call for heat, the blower relay is not energized. There is a thermostatic switch (FCC) that energizes the indoor blower motor through the blower relay Normally Closed contacts (B5) when the heat exchanger reaches a preset temperature.

Tommy

 

[Paperman]

That unit uses a single speed indoor blower motor, not a multi speed blower motor like a residential unit. There is no need to tie "Y" & "G" at the thermostat. The thermostat energizes the blower relay on a call for cooling, closing the blower relay Normally Open contacts (B2). On a call for heat, the blower relay is not energized. There is a thermostatic switch (FCC) that energizes the indoor blower motor through the blower relay Normally Closed contacts (B5) when the heat exchanger reaches a preset temperature.

Tommy

So that leads me to believe yes the thermostat has internally tied the y&g together as it seems that is how you describe it functioning. The wiring diagram was not make sense but now knowing that i have it straight in my head. Thank you all.