Troubleshooting The Cm737 - Honeywell CM737 User Instruction

4 Troubleshooting the CM737

Symptom
A flashing symbol
appears on the display within
one minute of the CM737 being
powered on.
A symbol appears
permanently (no flashing) on
the display.
Display is blank
A flashing symbol
appears on the display after the
CM737 being operating for a
period of time
A flashing symbol
appears on the display and the
room temperature is replaced
by "—"
Possible Cause
The CM737 receives power
supply from the heating
appliance, but no information.
Communication error due to an
interrupt or short circuit in the
link between the heating
appliance and the CM737.
After installing the CM737 no
power to the heating appliance
is supplied and the
rechargeable battery hasn't
been charged (takes max 1hr
until fully charged).
The power supply or the
communication link between the
CM737 and the heating
appliance has been interrupted
for more than 8 hrs.
The heating appliance is
showing an error
Internal fault in the temperature
measuring circuit.
15
Remedy
The CM737 is not connected to
the correct terminals of the
heating appliance.
Check if the wiring is connected
to the Open Therm connection
terminals of the heating
appliance.
The heating appliance is not
configured correctly.
Contact Alfa Laval.
Check if the power supply cable
of the heating appliance is
connected.
Check the wiring.
Contact Alfa Laval.
Check if the power supply cable
of the heating appliance is
connected otherwise contact
Alfa Laval.
Check if the power supply cable
of the heating appliance is
connected. After the power is
restored the time may need to
be adjusted – otherwise contact
Alfa Laval.
Press the button, to see the
error code. This fault code
depends on the type of heating
appliance See 4.1 Fault Codes
on the CM737.
Contact Alfa Laval.
CM737
User instruction