SA-Series Technical Manual
29
Cambridge Air Solutions
TROUBLESHOOTING INSTRUCTIONS
TROUBLESHOOTING GUIDE
Problem
Possible Cause
Corrective Action
I. No Blower Operation
(Continued on
next page)
1. Unit in Reset
a) Outside temperature below LTC setpoint
in Vent Mode
b) Gas valve not energized during call for
heat cycle
a) Turn unit OFF momentarily and turn unit
ON
b) See Problem III
2. Heater Power
a) Disconnect in OFF position
a) Turn disconnect ON
3. Mode Selector Switch (CE-Smart
TM
)
a) Switch in OFF position
b) Defective switch
a) Place switch in proper mode
b) Replace switch
4. Operating Thermostat
a) Thermostat satisfied
b) Open in thermistor circuit
c) Defective thermostat
a) Adjust thermostat, if applicable
b) Check wiring or replace thermistor
c) Replace thermostat
5. Blower Service Switch
a) Switch in OFF position
b) Defective switch
a) Place switch in REMOTE position
b) Replace switch
6. Control Transformer
a) No input voltage
b) Blown control fuse
c) Defective transformer
a) Check disconnect and supply fusing
b) Replace control fuse
c) Replace transformer
7. Class II Transformer
a) No output voltage
b) Defective transformer
a) Check supply voltage
b) Replace transformer
8. Multi-Functional PC Board
a) No input voltage on Terminal G (RCS)
b) Improper wiring
c) Defective board
a) Check voltage in RCS
b) Check wiring
c) Replace multi-functional PC board
9. Inlet Damper (optional)
a) Defective end switch
b) Defective damper motor
a) Replace damper assembly
b) Replace damper assembly
10. Motor Starter
a) Coil open (Defective)
a) Replace starter
11. Motor Protection
a) Overload tripped
b) Overload defective
a1) Check primary power source
a2) Allow motor to cool (SA250)
Reset overload relay (SA350)
a3) Check motor amps
a4) Check overload setting (SA350)
b) Replace motor (SA250)
Replace overload relay (SA350)
12. Motor
a) No input voltage
b) Improper voltage
c) Defective motor
a) Check primary power source
b) Consult factory
c) Replace motor
13. Blower
a) Defective or locked bearings
b) Physical damage
a) Replace or repair blower (SA250)
Replace bearings (SA350)
b) Replace or repair blower
