Part number 550-142-058/0811
87
WM97+
gas
-
fired
water
boiler
—
Boiler Manual
Troubleshooting
(continued)
Display
Condition
Diagnostics
Corrective Action(s)
RETURN >
SUPPLY
Occurs when a return water
temperature is greater than
the corresponding supply
temperature by 10ºF or more.
Automatically resets when
condition no longer exists.
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 34
.
Verify proper boiler circulator speed setting in the control module.
TEMPERATURE
SENSOR
Occurs when a temperature
sensor has electrically shorted
(SHORT) or has become
disconnected (OPEN).
Will automatically reset if the
condition clears
Check all the temperature readings of the boiler on the DIAGNOSTICS -
TEMPERATURES menu to determine if any sensors are currenty displayed
as SHORT or OPEN. Compare this to the boiler temperatures recorded
in the DIAGNOSTICS - ERRORS - LOCKOUT HISTORY # - TEMPERATURES
during the last several lockout conditions.
Determine which sensors are suspect and measure their resistance
value and compare it to the values shown in
Figure 83, page 83
. If the
resistance values are incorrect replace the temperature sensor. Refer to
repair parts section for proper part number.
OUTDOOR TEMP is the optional outdoor air temperature sensor. If this
are not being used they will always be shown as OPEN. This is normal
unless the sensors were installed.
Check wire harness for loose connections and pin engagement at sensor
connection, chassis mount connection through control housing, and the
control module. Unplug connection at sensor and at control module
and check continuity between ends.
If problem persists after checking items above replace control module.
Refer to repair parts section for kit number.
Occurs when dual
temperature sensors values
have spread by more that
10ºF if the burner is on
Automatically resets when
sensors are within 10ºF.
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. If measured resistance values of sensors
convert to temperatures seperated by more than 10ºF replace the sensor.
FLUE TEMP
TOO HIGH
Occurs when flue
temperature sensor exceeds
216ºF
Automatic reset occurs if
temperature drops below 216ºF
for 2.5 minutes.
Manual reset is required if the
temperature rises above 225°F.
Reset using manual reset screen
on display
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. In addition inspect heat exchanger
combustion chamber and flueways for abnormal wear or buildup.
Inspect vent system for abnormal wear or damage.
Contact Weil-McLain Technical Support.
LOW WTR
CUTOFF OPEN
Occurs when internal low
water cutoff contacts open
Automatic reset occurs if
contacts are open at least one
second, but less than 5 seconds
Manual reset of control module
if contacts are open longer than
5 seconds
Check for low water condition in system. Repair system as necessary
refer to piping section of this manual.
If low water condition does not exist, check Diagnostics - Inputs screen
to view status of Low Water Cutoff. If shown as OPEN check wiring
between LWCO and control module.
Troubleshooting
(continued)
Figure 88 Troubleshooting suggestions for WM97+ boilers —
Fault displays, diagnostics and corrective actions
(cont.)
