Precision Control Systems 915 - Manual (Page 19)

Page 16 of 21
Maintenance & Troubleshooting
Routine Maintenance
The following bimonthly routine maintenance is suggested.
1. Remove power connection to the system. Lock out power if possible. Carefully vacuum any
dust or dirt collecting within the enclosure. Use caution to not disturb the wiring. Service more
often in dusty locations.
2. Clean the outside of the enclosure with glass cleaner and a soft cotton cloth as necessary.
Troubleshooting
Symptom Action
Heater Contactor will not
energize 1. Verify line voltage is applied to the main disconnect switch.
2. Verify remote heater open, remote process interlocks or water flow
switches (if used) are closed.
3. If not using remote heater enable interlocks or water flow switches,
verify the 2 pin jumpers are installed between TB 100 pins 2 to 3, 10
to 11, and 14 to 15.
4. Check fuses FU 1050, FU 1051, FU 107, FU 108 and TB 100 pin 1.
No output to load,
heaters, or lamps.
Setpoint switch is in
LOCAL mode. 1. Verify a 0-10 VDC signal is present on pins 2 and 3 of the 4-pin
power controller connector. This voltage is proportional to the setting
of the local setpoint potentiometer.
2. Verify that 24 VAC is present on the 2-pin connector of the power
controller.
3. If the COMMAND led on the power controller is not lit and the local
setpoint potentiometer is set greater than 100, refer to the power
controller manual regarding repairs.
No output to load,
heaters, or lamps.
Setpoint switch is in
REMOTE or AUTO.
Operation O.K. with
setpoint switch in
LOCAL. 1. Verify the polarity of the remote input. TB 100 pin 16 is positive, and
17 is negative.
2. Units with Temperature control option: Place temperature controller in
manual mode with 50 percent output. Verify 2.5VDC at TB 100 pins
16 and 17. Refer to the temperature controller manual regarding
repairs.
Full voltage cannot be
obtained. 1. Verify the line voltage. Load voltage maximum is approximately 98
percent of the line voltage.
2. Test in LOCAL setpoint mode. Set the ‘Local Setpoint’ potentiometer
to 900. The voltage should be 108 (120 volt line), 216 (240 volt line),
or 432 (480 volt line). Adjust the SPAN potentiometer of the power
controller as necessary.
3. Refer to the power controller manual regarding repairs.
Load voltage will not go
to zero. 1. Test in LOCAL setpoint mode. Set the ‘Local Setpoint’ potentiometer
to 000 dial divisions. Adjust the zero potentiometer until the voltage is
0 volts.
Section 5