Mhpul - Marstair WM Technical Manual

SPECIFIC FAULT DIAGNOSIS FOR WM L UNITS
CONDITION
Check for alarms
i LEDs flashing - see table below
If NO external connections are made to alarm terminal 5, the presence of an alarm condition can be tested for by checking for mains
ii
voltage at terminal 5; full mains voltage = Alarm; less than mains voltage = Clear.
The outdoor unit can be caused to operate for test purposes by temporarily linking live directly to terminal 3
(up to 20 seconds delay)
L Outdoor unit runs continually at high
speed
If all external devices test O.K. the outdoor unit pcb must be replaced
M No LED's lit or flashing
N All LED's lit, one flashing
Indoor unit continues after stop/off
P
command
Q Unit will not respond to infrared
commands.
No audible answer signal
Unit does not switch on/off at
R
intended times
Unit not running in intended
S
mode/temperature
Fan does not run at the intended
T
speed
U Short cycles between cool and heat
First operation, room is overcooled
V
or overheated by 2 / C
W Handset will not transmit
X Compressor runs on
HANDSET
If the handset fails to respond to button operations, disconnect and then reconnect the battery.
The previous programme state is retained in the memory for a few seconds provided none of the user buttons are pressed.
LED STATUS AND ALARM INDICATIONS
Status Displays
Cool Dry
D I
Green Red
OFF OFF
OFF
ON
OFF
ON
OFF OFF
OFF
BLINKS
OFF OFF
OFF
ON
OFF OFF
Diagnostics
OFF
BLINKS x 4
OFF
BLINKS x 4
BLINKS x 4 BLINKS
OFF
BLINKS x 1
OFF
BLINKS x 2
POSSIBLE CAUSE
Charge link still fitted
MHPUL in heating
Minimum speed adjustment set too high
Unit commanded to be OFF
No mains supply or internal fuse blown. (Fuse
F2 on internal control board blown during
configuring)
Fan motor plug disconnected
Motor internal thermal protector operated
Cables to fascia not connected
Circuit board fault
High water level
Temperature sensor problem
Resistor problem (non MHPUL)
Outdoor sensor problem (MHPUL)
Overrun of 30 seconds in heating
Battery discharged
Handset corrupted
Power cut has occurred
Power has been shut off for three or more
days, unit is exercising default programme
Heat Pumps Only
System oversized for room
Set point temperature reverts to normal after
deadband is reached or 20 minutes of
operation
Heating commands
Any commands
Automatic minimum run time of 1.5 minutes Normal
Fan Heat
4 F
DIAGNOSTICS
Red Amber
No power, manual OFF, timed OFF, condensate
OFF OFF
high level, fault in condensate control
OFF OFF Cooling mode selected
OFF AUTO - predominantly cooling
BLINKS
OFF Heating mode selected
ON
OFF AUTO - predominantly heating
ON
OFF Fan mode selected
ON
OFF OFF Dry mode selected
OFF Outdoor unit defrosting
BLINKS
OFF OFF Room sensor missing
OFF OFF Indoor coil sensor missing
OFF OFF Outdoor coil sensor missing
OFF Compressor overload
BLINKS
OFF Pump fault
BLINKS
--o--o--O--O--O--o--o--
-59-
ACTION
Remove charge link
Normal
Reset minimum speed
Transmit 'ON'
Check electrical supply and fuses
Reconnect fan motor plug
Check motor and rectify
Reconnect
Check circuit board and replace
Check pump circuit (if fitted)
See table below
Check resistor connected
Replace outdoor unit
interconnecting wiring
Normal
Replace battery
Reset
Send any command from the handset to
synchronise the timer
Use handset retransmit button
Fan runs at low speed until indoor coil is
warm, then changes to intended speed
Use cool or heat programmes NOT 'Auto'
Normal
Incorrectly configured - see page 23
Battery flat
sensor/check