LAARS M4-Ext - Installation Manual - Manual (Page 27)

Page 27 LAARS Modulating Controls M4 & M4-EXT
TROUBLESHOOT - NO HEAT
START
Does the control have
power?
Is the control in
SUMMER mode?
Turn control power
ON.
NO
YES
Select WINTER from
the Season menu.
YES
Is the SYSTEM
Relay AND any of the
Boiler Output Relay
lights ON?
NO
Check the wiring
from control to the
boilers and the
pump.
Check plumbing for
heat distribution.
YES
Does the
Output relays that are
ON have continuity?
YES
Contact Factory for
control troubleshoot.
NO
Is the control
display indicates a
SHUTDOWN or PROVE
status?
NO
Check SHUTDOWN or
PROVE signal source.
YES
Is any of the
System or Outdoor
Sensors Short or Open?
NO
Replace the faulty
sensor.
YES
Is the Outdoor
sensor reading above
the Outdoor Cutoff
setting?
NO
Either change the
Outdoor Cutoff setting
or wait for the
Outdoor temperature
to drop below that
setting.
YES
Is the SYSTEM Relay
light ON?
YES
The control is in DHW
Priority and is
providing all output to
domestic water.
NO
Check control heat
settings for proper
heating Reset Ratio or
Set Point.
NO