Weil-McLain WM97+100 Manual page 111

WM97+ Series 2
Troubleshooting
Figure 118 Troubleshooting suggestions for WM97+ boilers — Fault displays, diagnostics and corrective actions
Condition
Display
Occurs if a temperature
TEMPERATURE
sensor has electrically shorted
SENSOR
(SHORT) or has become
disconnected (OPEN).
Occurs if dual temperature
sensors values have spread by
more that 10ºF if the burner
is on
Occurs if flue temperature
FLUE TEMP
sensor exceeds 216ºF
TOO HIGH
Occurs if internal low water
LOW WTR
cutoff contacts open
CUTOFF OPEN
Aqua Logic (CWH)
TANK SENSOR
installations only:
FAULT—TOP
Occurs if Upper Tank Sensor
has electrical shorted (SHORT)
or has become disconnected
(OPEN).
Aqua Logic (CWH)
TANK SENSOR
installations only:
FAULT—
Occurs if Lower Tank Sensor
BOTTOM
has electrical shorted (SHORT)
or has become disconnected
(OPEN).
Occurs if display
DISPLAY COMM
communications out for 30
seconds
Part number 550-142-204/0117
-
GAS FIRED WATER BOILER
(continued)
Diagnostics
Will automatically reset if the
condition clears.
Automatically resets when
sensors are within 10ºF.
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.
Automatic reset occurs if
contacts are open at least one
second, but less than 5 seconds.
Manual reset of WM97+ control
if contacts are open longer than
5 seconds.
Will automatically reset if the
condition clears.
Will automatically reset if the
condition clears.
Automatically resets when
communication is re-
established.
— Boiler Manual
Corrective Action(s)
Check all the temperature readings of the boiler on the DIAGNOSTICS -
TEMPERATURES menu to determine if any sensors are currently 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 112, page 107. 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
WM97+ control. Unplug connection at sensor and at WM97+ control
and check continuity between ends.
If problem persists after checking items above replace WM97+ control.
Refer to repair parts section for kit number.
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. If measured resistance values of sensors
convert to temperatures separated by more than 10ºF replace the sensor.
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.
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 WM97+ control. If wiring is alright, then replace the
LWCO.
Check temperature readings in the DIAGNOSTICS — TEMPERATURES
menu to determine if any sensors currently display SHORT or OPEN.
Determine which sensor is suspect and measure its resistance value and
compare it to the value shown in Figure 112, page 107. If the resistance
value is incorrect, replace the temperature sensor. Refer to the repair
parts section for proper part number.
Check temperature readings in the DIAGNOSTICS - TEMPERATURES menu
to determine if any sensors currently display SHORT or OPEN.
Determine which sensor is suspect and measure its resistance value and
compare it to the value shown in Figure 112, page 107. If the resistance
value is incorrect, replace the temperature sensor. Refer to the repair
parts section for proper part number.
Check for a loose connection at the molex plug on the control and
connection on the back of the display.
(cont.)
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