I have a bit of a unique situation. Older building that heats and cools by pumping hot/cold water through pipes. My unit has an air handler that amounts to just blowing air over the hot or cold coils. This air handler has an old thermostat that I want to replace with a digital thermostat. Obviously, a change from the hot/cold sensor being used now.

So all I want to do is install a fan control system, like a White Rogers 90-113 in place of the current set up to turn the fan off and on, single speed. I think all I need from the current setup is the two wires to the fan motor, and the thermostat wires.

Am I oversimplifying, and if not how to I wire the fan controller to the fan motor and the fan controler/thermostat?

 

What controls your water valves?

 

How long should a shower drain pipe be? won't use a fan center with anything over 1/4 horsepower.
I pick up a NEMA 1 junction box and use a contactor and transformer for most of my 4 pipe chill water air handlers.

I use 24VAC power open / spring shut control valves.

 

First, thanks for your reply. Let me clarify, our building has a central bolier/chiller that circulates the fluid. My unit in this building simply blows air across the coils of my air handler, so managing the flow is not in my control or interest. The original thermostat senses heat/cold and knows to heat up to or cool down to the thermostat set point.

I want to get away from this old thermostat. It can and has been done on other air handlers in the building, but looking at the retro fit, it is a complicated mess, which defies what I think should be the simple process of just turning on/off the blower via thermostat set point. Thanks again, I hope I have made this clearer.

 

Since your blower is 120v..... a basic fan center would work ok to control the blower only.