Pneumatic Stats

Boiler Guy

Bill can you give me any information on TP973A1001-1 or TP923A1002 stats? Looking for calibration procedures or repair kits.

Thanks

BillW@honeywell

TP973's...

The TP973 can be used on one or two pipe pneumatic control systems. It's most commonly piped with a .005 (blue) restrictor, main air into single fitting side, 1 pipe to the stat, one pipe to the controlled device on the double fitting side. The A models are direct acting, B models reverse acting. They are still available, TP973A2209 is a complete kit: stat, satin chrome cover and mounting hard ware.

To calibrate, you'll need a 0-30 psi gauge, a CCT729A gauge adapter (football pin) and an CCT735A calibration screw driver. To calibrate, take the cover off the stat. Insert the gauge pin into the rubber calibration port on the stat. Set the yellow set point indicator to match what the red temp indicator is showing. Use the screwdriver to turn the calibration screw until the gauge reads 0 psi. Then turn the screw back in the opposite direction until the gauge reads 7 psi. Remove the gauge , re-install the cover, and set for the desired temperature. I hope this helps.

Boiler Guy

Thanks Bill

That is great info on the TP973.. Do you have anything on the TP923 in regards to calibration. I have looked at these units (107 to be exact) and cannot see a caliibration port. Am I missing something? I believe these are now obsolete, but I have to make a case for affordable repair or replacement. Most are still operating satisfactorily but nt terribly accurately. Any assistance will be greatly appreciated. Thanks

Boiler Guy

Bill

Any info available on the 923 stat?

BillW@honeywell

I don't find any TP923's...

as a good part number. There were some TP974's that were temperature sensors only, they had no calibration ports, and worked with either an RP908 or RP920 receiver controller. They only have one pipe connected to them, the "B" port. The main (M) port is blocked. They have no setpoint or temperature indication. I found a TP925, but that was a special item that was used only rarely, and doesn't even resemble a wall stat. Any additional info, even a picture will help.

Boiler Guy

TP 923

These stats are almost the same size and operation as a T87. They are silver and black in colour , mounted on a 1" deep "wall cup" where the copper lines are soldered into the base. I took the number directly off the stat body. Any info would be greatly appreciated. I suspect they are early '70's vintage. Thanks