Piping a ceiling mount steam fan coil unit

Bill_69

I am having trouble getting heat in a ceiling fan coil unit. My guess is heater is water logged, but not sure whether the trap is working. Steam line is piped in with a 24v control valve. (2position) Return line rises about 1 1/2' straight up, left turn into a Sterling thermostatic trap (similar to the angle traps used on radiators) Then piping drops down into the main return line. I have good steam to unit, but not sure if this trap is a good selection for this application. All the piping is above the unit heater. This might be a problem as well?

Steamhead

What pressure are you running?

Can you post a picture?

Bill_69

Can't post a picture. Pressure is probably 5-10 psi.

Steamhead

Sounds like the present return piping is creating a water seal that keeps the air from leaving the heater. But from your description, there is no reason it should be piped this way.

Repipe it so there is no uphill return piping, and change the thermostatic trap to an F&T.

Bill_69

Thank you.