Specifications

FM774/0708 BOOK 2 26
CO/CZ/CA/CR/CY/QA/QM/WW/EX/I FAULT FINDING
FAN FAULTS
FAULT Ref CAUSE ACTION
6. FAN COMES ON BY IT-
SELF (AND CAN BE
TURNED OFF AT KEYPAD)
6.1 Unit has sustained an electrical spike
on supply cable.
Confirm unit is wired on its own dedi-
cated supply.
6.2 Unit has sustained an electrical spike
on the low voltage keypad cable.
Fit a spike filter on both end of the low
voltage keypad cable.
7. FAN CUTS OFF 7.1 Loss of power to air-conditioner. Check display on keypad if keypad
illuminated suspect thermal overload.
7.2 Loss of power to motor. Confirm keypad is in ‘ON’ position.
7.3 Motor failure or shutdown due to in-
ternal (motor) thermal protection
(thermal overload).
Check run current, if running at more
than 120% of value on motor name
plate—replace motor
WATER FAULTS
8. WATER NOT ENTERING
UNIT Select “COOL” and
fault find as follows:
8.1 Isolation tap closed or filter blocked. Open tap and clean filter.
8.2 Solenoid time delay active. Wait 1 min for drain valve to close &
delay to end.
8.3 Keypad not signalling roof unit-
Drain LED not lit.
Replace keypad.
8.3a BMCU board not signalling roof unit.
Drain LED not lit.
Replace BMCU
8.4 No 24vac output Water Inlet on MRU. Replace MRU. Refer pg 19-20.
8.5 No 24vac output at MWL board. Replace MWL board.
8.6 MS board failure (If MS float is fit-
ted).
Remove 3-pin MS cable if no voltage
to solenoid replace MRU.
8.7 Solenoid mesh strainer blocked. Remove solenoid & clean mesh
strainer & check water quality. Rec-
ommend replace solenoid.
8.8 Solenoid coil open circuit or failed. Replace solenoid.
8.9 Pressure lock between solenoid &
non-return type isolation valve.
Relieve pressure & fit standard
isolation tap.
9. WATER CONTINUALLY
RUNNING FROM UNIT
Select “COOL” and fault find
as follows
9.1 Keypad or BMCU failure. If Drain LED not lit suspect 7-pin ca-
ble and/or keypad and/or BMCU.
9.2 Electric drain valve failure. (If MWL
float fitted.)
If 240v at drain terminals replace
drain valve or if no voltage at drain
terminals replace MRU.
9.3 MS board failure. (If MS float is
fitted.)
Remove 3-pin MS cable from MRU. If
240v at drain terminals replace drain
valve. If no voltage at drain terminals
replace MRU.
9.4 Solenoid passing water/continuously. Strip & clean solenoid diaphragm &
seating. Recommend replace sole-
noid.
9.5 Water level set too high. Adjust either Fluidmaster Float valve,
MS or MWL float level. Check for wa-
ter in float.
9.6 Counterweight Drain Valve
a) Leaking from hoses or plastic clips
Replace plastic clips (SP2041) or
hoses kit (SP2042).
Do not re-use clips.
b) Hoses Incorrectly connected
(Refer to pg 39)
Replace hoses kit (SP2042).
c) Physical or Mechanical
impairment of counterweight drain
valve body
Replace drain valve (SP2040).
9.7 Square section blue ‘O’ ring faulty Replace ‘O’ ring (SP2043).