Specifications

44 – Service VMBMH302
15 Troubleshooting
15.1 Alarm
Shown in display in the event of an alarm. To reset alarms 1-5, set the operating mode to OFF or cut the power
supply.
Message Meaning
HIGH PRESSURE ERROR Tripped high pressure switch. Compressor stopped. No hot water production.
LOW PRESSURE ERROR Tripped low pressure switch. Compressor stopped. No hot water production.
MOTOR P ERROR Deployed motor protection (Over current relay compressor), or deployed motor protection
for outdoor unit fan. Compressor stopped. No hot water production.
OUTDOOR SENSOR Fault in outside sensor. When the control system calculates the heat demand, zero degrees
is used.
SUPPLY LINE SENSOR Supply line sensor error. Everything stops except the heating system’s circulation pump.
RETURN LINE SENSOR Return sensor fault. Return temperature = Supply line – 5 is used. Calculated supply tempe-
rature limited to maximum 45°C.
HOT WATER SENSOR Fault on sensor for start temperature. No hot water production.
ERR PHASE SEQ. Alarm that indicates that there is an incorrect phase sequence to the compressor. Only dis-
play and only the first 10 minutes.
HIGH RETURN Alarm that indicates that high return temperature prevents the compressor’s operation.
RAD FLOW LOW The flow sensor produces an alarm when the water flow in the heating system becomes too
low.