Weil-McLain WM97+100 Manual page 110

WM97+ Series 2
Troubleshooting
Figure 118
Troubleshooting suggestions for WM97+ boilers — Fault displays, diagnostics and corrective actions
Condition
Display
Control is not receiving 24V
Nothing shown
power
on display
screen and
boiler will not
respond to call
for heat
Control is not receiving 120V
Nothing
power
is shown
in display
screen and no
other boiler
components are
operating
Occurs if the communication
Nothing is
is lost from the WM97+
shown on
control to the display.
display screen,
but boiler is
operating
Occurs if supply water
TEMP RISE TOO
temperature in heat
QUICKLY
exchanger rises faster than
2ºF per second during the
first two minutes the burner
is on.
Boiler Out temperature
SUPPLY 58F >
has exceeded the Boiler In
RETURN
temperature by more than
58ºF
Occurs if a return water
RETURN >
temperature is greater than
SUPPLY
the corresponding supply
temperature by 10ºF or more.
– 110 –
-
GAS FIRED WATER BOILER
(continued)
Diagnostics
Check wiring for short circuit or
incorrect wiring.
Check 3-amp low voltage fuse
on WM97+ control shown on
page 107.
Check transformer connection
to the WM97+ control per
wiring diagram. Check for 24V
output of transformer.
Check service switch and/or
circuit breaker to boiler turned
is on.
Is there 120 Volts at the service
switch?
Is the WM97+'s ON/OFF POWER
SWITCH located on top of the
boiler.
Check for 120 Volts at the line
voltage terminal block located
inside the top left electrical
compartment.
Inspect 12-amp fuse as shown
on page 107. Replace if
necessary.
Check for loose connections
and proper pin alignment/
engagement on the WM97+
control's plug P9 and the back
of the display circuit board.
Cycle power off and on using
boiler power switch and check
for operation.
Automatically resets after 1
minute delay or using manual
reset on display.
Manual reset is necessary after 5
automatic resets have occurred
during the same Priority heat
demand. Reset using manual
reset screen on display.
Automatically resets after 30
second delay or using manual
reset on display.
Automatically resets when
condition no longer exists.
— Boiler Manual
Corrective Action(s)
Correct wiring per wiring diagram including connection of transformer
to the WM97+ control.
Replace fuse with proper part found in replacement part section of this
manual. If fuse blows again recheck wiring per diagram.
Replace transformer if it is receiving 120Vac, but not outputting 24Vac.
Turn on service switch to power boiler.
Troubleshoot and correct the power supply to the service switch.
Turn the WM97+'s power switch to ON.
Correct wiring inside the control pod using the wiring diagram in this
manual.
Replace the fuse with proper part found in the replacement part section
of this manual. If fuse blows again recheck wiring per diagram.
Check for continuity on the wire harness from the display to the WM97+
control. See repair parts section for proper replacement part.
Replace with new display module. See repair parts section for proper
replacement part.
Verify water pipe is installed correctly per instructions in this manual.
Verify proper circulator and speed for boiler size and system
requirements.
See message displayed TEMPERATURE SENSOR and follow procedure for
loose connections.
Verify water pipe is installed correctly per instructions in this manual.
Verify proper circulator and speed for boiler size and system
requirements.
See message displayed TEMPERATURE SENSOR and follow procedure for
loose connections.
Verify proper flow direction of the boiler circulator. This circulator must
be installed to push water through the boiler's return pipe as shown on
page 40.
Verify proper boiler circulator speed setting in the WM97+ control.
Part number 550-142-204/0117