Weil-McLain WM97+100 Manual page 112

WM97+ Series 2
Troubleshooting
Figure 118 Troubleshooting suggestions for WM97+ boilers — Fault displays, diagnostics and corrective actions
Condition
Display
Occurs if manual or automatic
LIMIT OPEN
reset l imit op ens.
Boiler temperature sensor
HIGH TEMP
reached High Temp Limit
LIMIT
setting (no higher than 200°F)
Occurs if flame is detected
FLAME FAULT
when there should be no
flame
The WM97+ control has
GAS VALVE
detected a problem with it
FAULT
gas valve output circuit
– 112 –
-
GAS FIRED WATER BOILER
(continued)
Diagnostics
Automatic external limit will
reset 2½ minutes after external
limit device closes.
Manual limit fault must be reset
by choosing Reset Lockout on
the display.
Reset using manual reset screen
on display.
Reset using manual reset screen
on display.
Control will do automatic retry;
lockout if retry unsuccessful;
retry 1 hour after lockout —
restart if condition cleared, but
lockout requiring manual reset if
condition still present.
Requires manual reset if control
is in lockout.
— Boiler Manual
Corrective Action(s)
Is there an external safety device connected? If yes, trouble shoot the
external limit to determine and correct the cause that opened the limit.
Also check for loose wiring connections.
Remove the top right electrical cover and inspect the connector.
Ensure a jumper is installed across the MAN LIMIT terminals if not using a
manual reset external limit.
Ensure a jumper is installed across the AUTO LIMIT terminals if not using
a automatic reset external limit.
Verify that high limit setting is at least 10°F above the setpoint
temperature.
Verify all isolation valves are open and circulators are programmed into
the WM97+ control properly.
The internal boiler circulator can be configured to turn on or off with
DHW and heating zones. Refer to the WM97+ control Setup section to
configure these properly for the system.
Verify water pipe is installed correctly per instructions in this manual.
Verify proper circulator sizing for boiler size and system requirements.
See message displayed TEMPERATURE SENSOR and follow procedure for
loose connections.
Burner may be operating too hot due to incorrect combustion. Inspect
flame and conduct combustion test.
Force boiler into hi-fire. Check flue gases with combustion analyzer and
correct using the maintenance and startup procedure in this manual.
Verify FLAME SIGNAL value quickly goes to zero on the DIAGNOSTICS -
INPUTS screen when the gas valve closes.
Check for flame at burner via flame current with burner off. Turn boiler
off and watch flame through observation port. If flame continues after
shutdown replace gas valve and venturi.
Check wire harness connections between gas valve and WM97+ control.
Check resistance between control and gas valve.
Disconnect low-voltage wires connected to the boiler low-voltage
terminal strip. Check all wire leads from system from system for stray
voltage. Any voltage in excess of 0.5 volts will cause gas valve fault
failures. Correct the cause of stray voltages before reconnecting wires.
After correcting problem, check to see if gas valve fault issue is corrected.
If lockout reoccurs replace WM97+ control.
(cont.)
Part number 550-142-204/0117