Sterling SCW Series installation manual Checking Motor Direction, Compressor, Water Pump

•No steam, hot air or fume exhausts drawn into the condenser coils.

•Service accessibility.

SCW Series condensing pressure

with 95ºF (35ºC) condenser air

R-134a = 171 psi (1,179 kPa/11.79 bars)

Note: Due to the variables involved in remote air-cooled condenser installations, no set or standard piping procedure exists. Each installation must be designed and installed by qualified persons. Follow the instructions supplied with the condenser.

3-11 Checking Motor Direction

Compressor

Check Compressor Rotation Before Starting Unit!

1.Connect a phase monitor and phase incoming power ABC.

2.Connect a refrigerant gauge to the suction service valve. Fully front seat the service valve and open one full turn.

3.Bump start the compressor by switching off then on quickly 0.5 to 1 second. If the rotation is correct, the suction pressure will drop immediately. A rise in pressure will indicate the wrong rotation. If this occurs, change over two electrical phases of the incoming power supply (do not change phase at the compressor starter).

Note:

•Never switch contactor leads or motor leads for reversing rotation.

•Do not use contactor or motor leads for phase matching.

•Compressor damage will occur if the compressor is run in reverse. The compressor motor protector checks for correct phasing and will not allow it to start in reverse.

•If you discover that compressor rotation is reversed, correct it by switching any two main power leads into the disconnect switch or distribution block on the unit.

Water Pump

A positive pressure of 20 to 30 psi (137.9 to 206.8 kPa/1.38 to 2.07 bars) on the TO PROCESS line indicates correct pump rotation.

Page 26 of 77 SCW Series Central Chilling Stations