1-877-420-1330
50Hz Quest 155
Installation, Operation and Maintenance Instructions
11
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3. Dirty air filter(s) or air flow restricted.
4. Excessively restrictive ducting connected to unit.
No ventilation. Ventilation is being called for.
1. Loose connection in ventilation control circuit
2. Loose connection in damper power circuit.
3. Defective fresh air damper.
Unit removes some water, but not as much as expected.
1. Air temperature and/or humidity have dropped.
2. Humidity meter and or thermometer used are out of calibration.
3. Unit has entered defrost cycle.
4. Air filter dirty.
5. Defective defrost thermostat.
6. Low refrigerant charge.
7. Air leak such as loose cover or ducting leaks.
8. Defective compressor.
9. Restrictive ducting.
10. Optional Condensate Pump Safety Switch open.
Unit Test to determine problem:
1. Detach field control wiring connections from main unit.
2. Connect the 24V and FAN pigtails from the main unit together; only the impeller fan should run. Disconnect the
wires.
3. Connect the 24V and DEHU pigtails from the main unit together; the compressor and impeller fan should run.
4. If these tests work, the main unit is working properly. You should check the control panel and field control wiring for
problems next.
5. Remove the control panel from the mounting box and detach it from the field installed control wiring. Connect the
DEHU, 24V, and FAN terminals from the control panel directly to the corresponding colored pigtails on the main
unit. Leave the, DMPR and COM terminals disconnected!
6. Turn on the fan switch; the impeller fan should run. Turn off the fan switch.
7. Turn on the humidity control; the compressor and impeller fan should run.
8. If these tests work, the problem is most likely in the field control wiring.
7.4 Refrigerant Charging
If the refrigerant charge is lost due to service or a leak, a new charge must be accurately weighed in. If any of the old
charge is left in the system, it must be recovered before weighing in the new charge. Refer to the unit nameplate for the
correct charge weight and refrigerant type.
7.5 Impeller Fan Replacement
The motorized impeller fan is a unitary assembly consisting of the motor and impeller fan. If defective, the complete
assembly must be replaced.
