58
Table 5 — Troubleshooting (cont)
LEGEND
PROBLEM
POSSIBLE CAUSE
POSSIBLE SOLUTION
Coil Freeze
Cooling coil freeze protection thermo-
stat tripped
(Auto-reset when freeze cleared)
Freeze thermostat is normally closed, opens during freeze.
Where fitted, the thermostat will disable the cooling action
(sometimes the entire system) during coil freeze conditions.
Use the unit
’
s wiring schematic to investigate.
Dirty or blocked air filter
Clean/replace filters as necessary. (See page 55 for filter
removal and cleaning instructions.)
System head pressure set too low.
Check condensing pressure. Low ambient kit installation may
be required.
Loss of refrigerant
Check system for refrigerant leaks and repair before recharg-
ing.
Water Leaking from Unit
(also see Condensate High Level Sec-
tion)
Condensate plug loose or missing
Check that the rubber condensate plug is securely fitted to the
underside of the unit
’
s polystyrene drip tray. On some models
this is located underneath the fascia support rails on the pump
side of the unit.
Unit installed unevenly
With fascia removed, ensure that the unit chassis is level (at the
face) both front to back and left to right, to ensure correct con-
densate flow.
Condensate drain piping installed
incorrectly
Check that the site installed condensate gravity drain slopes
‘downhill
’
away from the unit. (See page 39 of this manual for
installation guide.)
Blocked/kinked condensate pipe
Check condensate piping for blocks/kinks, clear as necessary.
Check for a water tight connection between the condensate
outlet and the site installed condensate gravity drain.
Condensate pump blocked or failed
Clear any blockages and ensure that power is being applied to
the pump. If the pump still does not run, replace the pump.
Float switch failure
Check that the float switch operates correctly and is properly
positioned. Float switch is normally closed, opens on rise of
water level.
No Heating (Hot Water)
Incorrect MODE setting
(Microprocessor units only)
Check that the transmitter MODE is set to Heat or Auto Mode.
Set point too low
Check the set point on the transmitter or wall mounted thermo-
stat and adjust if necessary.
Blocked or dirty filters causing low
airflow
Check condition of filters. (See page 55 for filter removal and
cleaning instructions.)
No hot water/pumps failed
Check hot water source and supply to unit.
Faulty valve/actuator
Check actuator by manually opening and closing valve, replace
if faulty.
Faulty heater relay
Check signals to relay and check action of relay contacts.
Replace relay or PCB if necessary.
No Heating (Electric Heat)
Incorrect MODE setting
(microprocessor units only)
Check that the transmitter MODE is set to Heat or Auto Mode.
Set point too low
Check the set point on the transmitter or wall-mounted thermo-
stat and adjust if necessary.
Overheat cutout tripped
(Also see Electric Overheat section)
Investigate cause of over heat condition.
•
Possible low airflow, check filter condition.
(See page 55 for filter removal and cleaning instructions.)
•
Possible fan failure. Check fans.
(See Fans Will Not Run section.)
Remove power from unit and reset manual overheat cutout by
rubbing. DO NOT PRESS. Consult Factory for instruction if
necessary.
Heater element failed
Investigate and replace if necessary.
Faulty heater relay
Check signals to relay and check action of relay contacts.
Replace relay or PCB if necessary.
Electric Overheat
Automatic or manual reset overheat
cutout tripped
The electric heat circuit contains one automatic reset and one
manual reset overheat cutout protection switch for each electric
heat element fitted to the unit. The cutouts are wired in line with
the main power flowing in each element and operate as
described below.
•
Automatic cutout: If the auto cutout trips, the electric heat is
temporarily disabled until the unit temperature falls and
causes the overheat cutout to automatically reset.
•
Manual cutout: If the manual cutout trips, the electric heat is
disabled until the unit temperature falls and the overheat
cutout is manually reset. It will typically take five minutes for
the unit temperature to fall sufficiently to allow the cutout to
be reset. The cutout should only be reset by a qualified and
competent electrician and with the main power switched off.
Ensure the elements have cooled sufficiently.
LED —
Light-Emitting Diode
PCB —
Printed Circuit Board
