Diagnostics
RT-SVX34F-EN
111
Troubleshooting
Table 83. Troubleshooting
SYMPTOM
PROBABLE CAUSE
RECOMMENDED ACTION
A.
Unit will not operate.
No Heat, No Cool or No
Fan operation.
1.
No power to the Unit.
1.
Check line voltage at service disconnect.
2.
No power to the RTRM.
2.
Check for 24 VAC at RTRM J1-1 to system ground.
3.
Zone Sensor Module (ZSM) is
defective or MODE circuit is open. (VAV
only)
3.
See Zone Sensor Module (ZSM) Test Procedures or short MODE input
on VAV units.
4.
RTRM is defective.
4.
If 24 VAC is present at the RTRM J1-1 to ground, the LED on the RTRM
should be on. If the LED is not lit, replace the RTRM.
5.
Supply Fan Proving (FFS) switch has
opened.
5.
Check the IDM and belts, replace as necessary.
6.
Emergency Stop input is open.
6.
Check the Emergency Stop input.
CV or SZ VAV Units only
B.
Unit will not Heat or
Cool, but the Fan
switch operates.
1.
Zone Sensor Module (ZSM) is
defective.
1.
Refer to the Zone Sensor Module (ZSM) Test Procedures.
2.
Problem in (ZSM) wiring.
2.
Disconnect the ZSM wiring at RTRM and test the wires using the Zone
Sensor Test Procedures to locate any wiring problems.
3.
RTRM is defective.
3.
Disconnect the ZSM wiring at the RTRM and perform the Zone Sensor
Module (ZSM) Test Procedures. If within range, replace RTRM.
CV, SZ VAV or VAV (Unoccupied)
C.
Unit heats and cools, but
will not control to set point.
1.
Zone Sensor Module (ZSM) is
defective.
1.
Refer to the Zone Sensor Module (ZSM) Test Procedures.Refer to the
Default Chart.
2.
Thermometer on the ZSM out of
calibration.
2.
Check and calibrate the thermometer.
D.
CPR1 will not operate,
ODM's will operate.
1.
Compressor failure.
1.
Test compressor, mechanically and electrically. Replace if necessary.
2.
Wiring, terminal, or mechanical CC1
contactor failure.
2.
Check wires, terminals and CC1. Repair or replace if necessary.
3.
LPC1 has tripped
3.
Leak check, repair, evacuate and recharge as necessary. Check LPC1
operation.
E.
CPR1 operates, ODM's will
not operate.
1.
ODM has failed.
1.
Check ODM's, replace if necessary.
2.
ODM capacitor(s) has failed.
2.
Check ODM capacitors, replace if necessary.
3.
Wiring, terminal, or mechanical CC1 or
CC2 contactor failure.
3.
Check wires, terminals,CC1 and CC2. Repair or replace if necessary.
4.
ODF 20 or 34 relay has failed
4.
Check for proper voltage and contact closure. ODF20 and 34 have a 24
VAC holding Coil. If voltage is present, replace relay.
5.
RTRM is defective
5.
Locate the P3 connector on the RTRM. Check for 24 VAC at terminal
P3-6. If 24 VAC is not present, replace RTRM.
F.
CPR1 and ODM1 will not
operate.
1.
No power to CC1 coil. Possible Cool
Failure
1.
Check wiring, terminals and applicable controls (CCB1, HPC1, TDL1,
WTL1, LPC1)
2.
CC1 coil defective. Cool Failure
Indicated.
2.
Check CC1 coil. If open or shorted, replace CC1.
3.
CC1 contacts defective.
3.
If 24 VAC is present at CC1coil, verify contact closure.
4.
RTRM is defective.
4.
If 24 VAC is not present at CC1 coil, reset the Cool Failure by cycling
the main power disconnect switch. Verify system MODE is set for cooling
operation. If no controls have opened, and CC1 will not close, replace
RTRM.
5.
LPC1 has tripped
5.
Leak check, repair, evacuate, and recharge as necessary. Check LPC1
operation.
