070.655-IOM (FEB 22)
Page 26
SBTP Rotary Screw Compressor
Maintenance
Troubleshooting the SBTP compressor
Problem
Cause
Solution
The slide valve or
slide stop does not
move
Four-way hydraulic control valve has failed
Repair or replace
Slide stop indicator rod is stuck
Contact Johnson Controls-Frick service for as-
sistance
Incorrect wiring or resistance of S.V. or S.S.
feedback devices
Check wiring and resistance
Compressor is not running with sufficient oil
pressure
Check the oil pressure
Unloader piston is stuck
Contact Johnson Controls-Frick service for as-
sistance
Piston seals are worn out or damaged
Contact Johnson Controls-Frick service for as-
sistance
NOTICE
Unless the Service Technician has been certified by Johnson Controls–Frick to rebuild our compressors, troubleshoot
-
ing the compressor is limited to identifying the probable cause. If a mechanical problem is suspected, contact Johnson
Controls–Frick Service. Do not attempt to disassemble compressor.
Troubleshooting the oil pump and system
Problem
Cause
Solution
Pump does not
produce enough oil
pressure at start-up
Service valves are closed
Open the service valves
Filter cartridges are blocked
Check PSID across filters
Strainer is blocked
Clean
Oil pressure regulator set too low or stuck
open
Readjust or repair
Pump worn out
Repair or replace
Oil pressure rap-
idly drops off when
compressor starts
Main oil injection throttling valve too open or
oil pressure regulating valve adjusted incor-
rectly
Readjust one or both of the valves as as
necessary
Noise and vibration
Pump strainer blocked
Clean
Pump worn out
Repair or replace
Oil pressure drops
as head pressure
increases
Normal behavior
Set main oil injection and oil pressure for maxi-
mum head pressure condition
Main unit filter psid
is too high
Filters are clogged
Replace
Oil is too cold
Allow oil to warm up and check again
Service valve on filter outlet is partially
closed
Open valve fully
