Fault Finding - Marstair 600E/M Technical Manual

FAULT FINDING

CONDITION
A Indoor fan motor will not run
B Inadequate cooling or heating
C Compressor and outdoor fan motor
will not run
Compressor runs, outdoor fan doesn't
D System runs for long periods and will Unit underrated for conditioned area
not cycle
Indoor coil dry or partly sweating
E Indoor coil frosting
If room temperature is also low
F Noisy unit
G Water leaking from unit
Units with lift pump or condensate pump No supply to pump or loose connection
H Pump always runs
I No heating
Overload tripped on three phase
J
units
K Outdoor unit does not operate
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POSSIBLE CAUSE
No electric supply at socket or switched fuse box
Unit wiring fault
Fan motor capacitor defective
Fan motor defective
Internal fuse blown
Dirty evaporator fins/filter
Evaporator motor not running
Refrigerant shortage or excess
Faulty or incorrectly set thermostat
Dirty condenser
Faulty compressor
LP cutout circuit open (if LP fitted)
LP cutout circuit open (if LP fitted)
No electric supply at socket or switch fuse box
Unit wiring fault
Capacitor, thermostat, relay or overload defective
Compressor failure
Controls not set properly
Off cycle delay operating
High condensate level detected
Pressure at sensor <200psig
Thermostat not operating correctly
Refrigerant shortage
Dirty condenser
Refrigerant shortage
Dirty evaporator fins/filter
Running in cool ambient without a head pressure
controller
Thermostat set too low or cooling permanently
Fan fouling cowl (outdoor unit)
Worn motor bearing
Casing or piping vibration
Loose parts or mounting
Bent fan blade
Blocked drain or filter
Pumping slowly
Pump windings shorted
Fouled sensor (5m condensate pump only)
Faulty sensor or pcb
Controls not set for heating
Unit wiring fault
Dirty evaporator fins/filter
Faulty thermostat
Faulty heater element
Faulty heater cutout
Reversing valve jammed
High voltage supply
Compressor failure
Fuses blown
No mains supply
Supply below 187V
Isolator switched off
Internal fuse blown
Data wires disconnected
No command signal
Off cycle delay operating
21/25
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ACTION
Check fuse rating and replace if necessary. Check
for loose electrical connections
Check wiring and connections
Replace if faulty
Replace if faulty
Clear fault and replace fuse
Clean if blocked
As in section A
Check for leaks. Repair, evacuate and recharge or
check for high head pressure and recover refrigerant
if necessary
Replace if faulty
Clean if necessary
Replace
Check as refrigerant shortage or excess
Check as above
Check fuse rating and replace if necessary. Check
for loose electrical connection.
Check wiring and connections
Replace if faulty
Replace if faulty
Check and rectify
If applicable, wait 3 minutes
See G
Normal: or short of gas
Check heat load against capacity
Check wiring, position of phial and operation
Check for leaks. Recover, repair, evacuate and
recharge
Clean fins if necessary
Check for leaks. Recover, repair, evacuate and
recharge
Clean if blocked
Fit head pressure controller
Reset or replace
Realign fan
Replace motor
Check cause and rectify
Find and tighten
Replace fan
Clear obstruction
Secure the supply
Check drain pipes; if clear, replace pump
Replace pump
Clean sensor
Replace sensor or pcb
Reset
Check wiring and connections
Clean
Check for signal; replace if faulty
Replace
Replace, (check for short circuiting)
A light tap may free it; preferably replace
Max rated voltage 254v -- check supply
Replace
Replace fuses and investigate reason for fuses
blowing
Check fuse rating and replace. Check for loose
electrical connections
Check supply
Turn isolator on
Check fuse and replace
Reconnect data wires
Check indoor unit
Wait in cooling for 3 minutes
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