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.
;Open the 1” (approx. 25 mm) makeup water valve and allow the tank to fill until the automatic float valve shuts off. The float level should be adjusted so the standing water level is 8” (20 cm) from the top of the tank.
;Check for proper pump rotation direction. To confirm proper rotation:
1.Observe a pump pressure gauge connected to the suction and discharge sides of the pump casing through two ¼” (approx. 6.4 mm) gauge cocks.
2.Close the gauge cock leading to the pump suction and open the gauge cock leading to the pump discharge.
3.Close the discharge butterfly valve, crack it open, then start the pump and observe the gauge.
•If the gauge indicates within 15 psi (103.4 kPa/1.03 bars) below the pump curve, pump rotation is correct. Pump rotation is clockwise opposite the shaft end.
•If the gauge indicates 20 psi (137.9 kPa/1.38 bars) or more below the pump curve, the pump is running backwards. Reverse rotation by interchanging any two power mains to the pump motor or starter.
•Recheck the pressure to be sure it increased.
Page 38 of 77 | SCW Series Central Chilling Stations |