Part number 550-142-058/0811
79
WM97+
gas
-
fired
water
boiler
—
Boiler Manual
Annual startup
(continued)
Check ignition wiring
1. Check ignition cable electrical resistance. A good cable will have
resistance between 900 and 1100 ohms. Replace if not acceptable.
2. Inspect boiler ground wire from heat exchanger access cover to
ground terminal screw.
3. Verify all wiring is in good condition and securely attached.
4. Check ground continuity of wiring using continuity meter.
5. Replace ground wires if results are not satisfactory.
Check all boiler wiring
1. Inspect all boiler wiring, making sure wires are in good condition
and securely attached.
2. Verify that all connectors are securely inserted.
Check control settings
1. Use the control module display to navigate through all settings.
Adjust settings if necessary.
2. Check settings of external limit controls (if any) and adjust if
necessary. Adjust as needed to accommodate the system design.
Perform startup and checks
1. Start boiler and perform checks and tests specified in this manual.
2. Verify cold fill pressure is correct and that operating pressure does
not go too high. Adjust water pressure and expansion tank charge
pressure as necessary.
3. Complete the check-out procedure on page 74.
Check low water cutoff service light
1. If the low water cutoff amber LED is on, the control requires service.
Follow the low water cutoff manufacturer’s instructions (shipped
with the boiler in the literature envelope).
Check burner flame
The boiler contains ceramic fiber materials. Use care
when handling these materials per instructions on
page 76 of this manual. Failure to comply could result
in severe personal injury.
1. Inspect flame through observation window using the procedure
on page 71.
2. If flame is unsatisfactory at either high fire or low fire, check com-
bustion values. If combustion is properly adjusted, turn off boiler
and allow boiler to cool down. Then remove burner and clean it
thoroughly using a vacuum cleaner or compressed air. Do not use
compressed air to clean burner if performed inside a building.
3. To access the burner, remove the heat exchanger cover plate fol-
lowing the procedure beginning on page 91.
4. When replacing the burner, ensure the burner gasket is in good
condition and correctly positioned. Follow all instructions on
page 91 to reinstall all components.
5. Restart the boiler.
6. Inspect the flame at high and low fire. If flame is still
not acceptable, check combustion values. If combustion
is properly adjusted, obtain a replacement burner from
Weil-McLain.
Check flame signal
1. Navigate to Diagnostics/Inputs on the control module
display (see Figure 60, page 55 for navigation instruc-
tions and Figure 69, page 64 for the complete Diagnos-
tics menus).
2. The flame signal value must be at least 75.
3. If the flame signal drops to less than 75, the control
module will attempt to correct by increasing the boiler
firing rate to increase flame signal.
4. A lower flame signal may indicate a fouled ignitor or
damaged ignitor insulation.
a. See “Inspect ignition electrode,” page 78 to remove
and inspect the ignitor.
b. If required, clean the igniter as instructed.
c. If cleaning the ignitor does not improve, ground
wiring is in good condition, and ground continuity
is satisfactory, replace the ignitor.
5. If flame signal still remains low:
a. Inspect the vent and air piping.
b. Check combustion values.
c. Then inspect the heat exchanger, following the
procedures given in this manual for removal and
reinstallation of the head exchanger cover plate and
other boiler components (see page 91).
d. Clean the exchanger as described in this manual if
necessary.
Figure 80
Flame signal shutdown values
Model
WM97+
Shutdown
flame signal
70
50
70 HA
50
110
50
110 HA
50
NOTE: “HA” means high altitude, 5500 feet or more above seal level.
