Trane RTWA 70-125 TON - Manual (Page 38)

38 RLC-SVD03A-EN
Compressor Capacity
Unload
NOTE: The following assumes that the compressor's slide valve is already
at some loaded position and %RLA is higher than the minimum noted in step
1.
1. Manually close the Unload toggle switch to continuously energize the
Unload Solenoid Valve.
2. If the %RLA decreases, then the Unload Valve and Slide Valve are operat-
ing properly.
3. If the %RLA does not decrease, observe the cylinder cavity pressure
reading.
4. If cylinder cavity pressure reading decreases to approximately the suction
1. Install toggle switches across load and unload solenoid
2. Install Pressure Gage on slide valve piston/cylinder cavity Schrader valve.
3. Start Unit.
Load:
4. Manually load compressor in short increments.
5. Does RLA increase? Check UCM Repeat
procedure
for unload
Replace
6. Does Cavity Press
increase to a level close
to discharge pressure? Slide valve mechanism bound
7. Does Magnetic Field on
Solenoid Coil exist? Solenoid valve mechanism bound
or unloader valve stuck open
8. Is wiring to valve OK? Check for open solenoid coil
9. Repair and reverify.
Figure 5 Manual Slide Valve Diagnostic Flow Chart - Load
No
Yes
Bad
Good
Yes
No
Yes
No
Yes
No