Emerson PFH020A-L, User Manual

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Troubleshooting
Liebert
®
Mini-Mate2
™
64
11.0 T
ROUBLESHOOTING
!
WARNING
Risk of electric shock. Can cause injury or death.
Open all local and remote electrical power disconnect switches before working within
electrical enclosures.
Hazardous voltage will be present at evaporator, condenser, reheat and humidifier even with
the unit turned Off at the control panel. With power and controls energized, unit could begin
operating automatically without warning.
Table 26 Troubleshooting
Symptom Possible Causes Check or Remedy
Unit will not start
No power to unit Check voltage at input terminal block.
Control voltage circuit breaker
(at transformer) open
Locate short and reset circuit breaker.
Float switch relay has closed
due to high water in the
condensate pan.
Has rubber band been removed from float switch? Check drain
and line. Access from bottom through discharge air grille. Power
must be cycled at the disconnect to reset.
Jumper not in place
Check terminal TB1-4 and TB1-5 for jumper or N/C contact.
Check Pins 1-8 and 1-9 for jumper or N/C optional
high-temperature sensor contact. Check Pins 5-4 and 5-5 for
jumper or N/C smoke detector contact.
No cooling
“Cooling” is not displayed at the
control panel.
Adjust TEMP control setpoint and sensitivity to require cooling.
Short cycle prevention control.
Control software delays compressor 3 minutes cooling, from
stop to start
Compressor contactor not
pulling in.
Check for 24VAC ± 2 VAC at terminals P4-8 and P4-4. If voltage
is detected, check contactor. If there is no voltage at P4-8 and
P4-4, check at terminals P2-3 and P2-8. If voltage, check
freezestat.
Compressor high head
pressure.
See below for cause.
Plugged filter/dryer. Replace filter/dryer.
Low refrigerant charge.
Check pressure gauges. See Tables 5 and 9 for recommended
pressures. At low ambient temperatures, proper refrigerant
charge is very important on units with Lee-Temp receivers.
Compressor high
head pressure
Insufficient air flow across
condenser coil
Remove debris from coil and air inlets.
Water/Glycol-Cooled only: No
fluid flowing through condenser.
Check fluid supply to regulating valve. Adjust valve if necessary.
Self-Contained, Air-Cooled only:
Condenser fan not operating
Check fan operation.
Reheat will not
operate
DIP switch not set to enable
reheat option
See DIP switch settings Table 20.
“HEAT” not displayed at the
control panel
Increase temperature setpoint to require heating.
Reheat safety open, defective
reheat contact or defective
board
Check voltage at P2-1 and P1-9 on interface board for 24 VAC ±
2 VAC. If voltage, check reheat contactor and reheat safety. If
no voltage, check wiring and/or replace board.
Element is burned out Turn off power. Check element continuity with Ohm meter.
GCD has tripped Replace GCD and heating element.
Display freezes and
control pads do not
respond
Static discharge
During period of low humidity, static electricity can cause the
control program to freeze or display incorrect information.
Although this is unlikely, the control can be reset by cycling
power from the disconnect switch.