Weil-McLain WM97+100 Manual page 113

WM97+ Series 2
Troubleshooting
Figure 118 Troubleshooting suggestions for WM97+ boilers — Fault displays, diagnostics and corrective actions
Condition
Display
BLOWER FAULT Blower unable to reach
required speed or does not
reach 0 RPM when turned off.
NOTICE: WM97+70 only —
The blower will not rotate
without a low voltage signal.
Unplugging the low voltage
blower wire harness will not
allow or cause the boiler to
rotate.
IGNITION Boiler went through 5 ignition
FAULT attempts and never detected
flame
Part number 550-142-204/0117
-
GAS FIRED WATER BOILER
(continued)
Diagnostics
Reset using manual reset screen
on display; WM97+ control will
check again after 1 hour and will
automatically restart if condition
is corrected
Automatically resets after 1 hour
or can be reset by performing
manual reset on boiler.
— Boiler Manual
Corrective Action(s)
Check wire harness for loose connections and pin engagement at blower
connections, chassis mount connection through control housing, and
WM97+ control. Unplug connection at blower and at WM97+ control
and check continuity between ends. Blower is connected to both low
voltage and line voltage harness.
Check Diagnostics - Inputs screen with boiler in standby mode and
blower not running. If BLOWER SPEED is not 0 RPM then replace blower.
If blower does not rotate during ignition sequence check for 120V power
at blower connection. If 120Vac power at blower motor and it doesn't
start replace blower. Check power at WM97+ control. If 120Vac is not
present at WM97+ control when boiler is powered replace WM97+
control. Refer to repair parts section.
Check condensate trap for blockage allowing condensate to accumulate
inside heat exchanger.
Check ignition cable connection.
Fouled, worn, bent, or faulty igniter.
Fouled igniters can be cleaned for additional use with steel wool.
Worn or badly fouled igniters should be replaced with the proper repair
part.
Igniter rods should be parallel with a 3.5 mm (0.138 in) spark gap for
70/110 and a 4.8 mm (0.189 in) spark gap for 155 models.
NOTICE: Thin white deposits on the igniter are typical, but brown or
black deposits could be the result of flue gas recirculation. Thoroughly
inspect the venting system and termination for the possibility of leakage
or flue gas feedback into the air line.
Dirty burner and/or heat exchanger will cause high back pressure and
poor ignition.
Follow procedure in maintenance section of this manual to clean burner
and heat exchanger. Visual inspection of flueways may not be sufficient
to diagnose condition.
Check combustion settings on high and low fire and adjust per setup
instructions if necessary.
Check incoming gas pressure with boiler off and at high fire. Adjust
within limits on rating label.
Verify correct boiler model is selected in control and high altitude is
selected for installations 5,500 feet above sea level.
Check ignition cable resistance. Should measure 1000 Ohms (+/- 50
Ohms).
Check for flue pipe and intake pipe restrictions or blockage.
Check burner fasteners and gaskets.
Check venturi gaskets and proper propane orifice bushing.
(cont.)
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