Screw Compressor Central Chiller
Chapter 3: Installation
31
13.
Check condenser fans for pressure switch settings as shown in the table below:
Fan
Set on
Set off
number
psi
KPa
bars
psi
kPa
bars
1
not applicable; Fan 1 is a variable-speed fan
2
140
1,069
10.7
105
828
8.3
3
150
1,172
11.7
115
931
9.3
4
160
1,276
12.8
125
1,035
10.3
5
170
1,379
13.8
135
1,138
11.4
14.
Connect the main power to the unit and bump-start it to check for proper rotation
direction. If the fans are operating backwards, reverse any two main power leads at
the incoming terminal block.
15.
Remove all tools, foreign matter and debris from the pump tank reservoir and piping.
16.
Complete all piping leading to and from the pump tank. Observe all applicable codes.
17.
Complete all electrical wiring. Observe all applicable codes.
18.
Prepare all related equipment in the system for operation.
19.
Check for proper compressor rotation direction. To confirm proper rotation, connect
a phase meter and phase incoming power in sequence (ABC).
Note:
x
Never switch contactor leads or motor leads for reversing rotation.
x
Do
not
use contactor or motor leads for phase matching.
x
Compressor damage will occur if the compressor is run in reverse.
The compressor motor protector checks for correct phasing and will
allow it to start in reverse.
x
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.
20.
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.
21.
Check for proper pump rotation direction. To confirm proper rotation:
a.
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.
b.
Close the gauge cock leading to the pump suction and open the gauge cock
leading to the pump discharge.
c.
Close the discharge butterfly valve then crack it open, open the pump suction
butterfly valve fully, then start the pump and observe the gauge.
1.
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
.
