Page 23
Operation Manual
LM7/24-2 Wall Controller
Operation Manual LM7-2 / LM24-2 Wall Controller
Document No. 0525-079
Ver. 1 190821
15. Troubleshooting
Condition
Causes or Check Points
The system does not start.
• Check that 5 minutes has passed from turn on time, as the system has in built safety
timers.
• Check thermostat settings are correct.
• Check the thermostat set-point is set low enough for cooling or high enough for
heating.
Air does not flow.
(Indoor Unit)
• Check Zones are switched on. (where fitted)
• During heating operation, air does not flow out for approx. 15 seconds after start
up, this prevents cold drafts.
• During the defrost of the outdoor unit in heating operation, the indoor fan will not
operate for several minutes, this is to prevent cold air being blown into rooms.
Cooling/Heating is not
sufficient.
• The cooling/heating function may not work effectively when the return air filter is
clogged with dust and dirt.
• Make sure the air inlet and air outlet on the outdoor unit are not blocked.
• The outside temperature is above or below the design conditions.
Steam from outdoor unit.
• It is caused by the defrosting of the outdoor unit in heating operation in cold
conditions.
Water from outdoor unit.
• This is normal during heating operation, it is due to water forming on the heat
exchanger.
Occurring of noises
• When heating or cooling is started or stopped, a swishing or gurgling noise may be
heard. This noise is generated by the refrigerant flowing between the outdoor and
indoor units.
• A whooshing noise may be heard from the outdoor unit during operation. This
noise is generated when the refrigerant changes direction in the defrost operation.
• On start up, the outdoor unit may be louder than normal for a few seconds whilst
the compressor reaches the designated speed and operating pressure.
• During defrost operation the compressor may generate more noise than normal.
Fault Codes
• When EXX is displayed on the wall controller, take note of the digits after E and
contact your installer.
Set-temp can’t be
adjusted.
• Check your wall control set-temp limits are not being exceeded.
• Check the upper and lower temperature are set correctly. (See Page 20)
7-day time clock is not turning
the air conditioner on and off.
(7-Day programmable model only)
• Check the time clock is activated. (See page 15)
7-day timec lock is not
accepting times you enter.
(7-Day programmable model only)
• Check you don’t have times overlapping from another day.
• Make sure your not trying to set the time past the maximum allowable. (See
programming past midnight Page 17)
Before contacting your installer, please have your air conditioners
Model No. and Serial No. with you. (See Page 5)
