Check Flame Signal; Check Control Settings; Check Burner Flame - Weil-McLain WM97+70 Manual

WM97+ -
gas fired water boiler
Annual startup
Check ignition wiring
1. Check ignition cable electrical resistance. A good cable will
have resistance between 950 and 1050 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 condi-
tion and securely attached.
2. Verify that all connectors are securely inserted.

Check control settings

1. Use the WM97+ control display to navigate through all set-
tings. 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 92.
CWH installations only — verify
operation per CWH manual
1. If a Companion Water Heater (CWH) is installed, follow
instructions in the CWH manual to set and verify operation
of the water heater.
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 instruc-
tions (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 94 of this manual. Failure to comply could
result in severe personal injury.
1. Inspect flame through observation window using the pro-
cedure on page 88.
Part number 550-142-085/0712
— Boiler Manual
(continued)
2. If flame is unsatisfactory at either high fire or low fire, check
3. To access the burner, remove the heat exchanger cover plate
4. If replacing the burner, ensure the burner gasket is in good
5. Restart the boiler.
6. Inspect the flame at high and low fire. If flame is still not ac-

Check flame signal

1. Navigate to Diagnostics/Inputs on the WM97+ control
2. The flame signal value must be at least 75 for a WM97+70
Figure 101
3. A low flame signal may indicate a fouled ignitor or damaged
4. If flame signal still remains low:
combustion 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.
following the procedure beginning on page 110.
condition and correctly positioned. Follow all instructions
on page 110 to reinstall all components.
ceptable, check combustion values. If combustion is properly
adjusted, obtain a replacement burner from Weil-McLain.
display (see Figure 80, page 72 for navigation instructions
and Figure 89, page 81 for the complete Diagnostics menus).
or 110, or at least 160 for the WM97+155. If the flame signal
drops below this level, the WM97+ control will attempt to
correct by increasing the boiler firing rate to increase flame
signal.
Flame signal shutdown values
Model Shutdown
WM97+ flame signal
70 50
70 HA 50
110 50
110 HA 50
ignitor insulation.
a. See "Inspect ignition electrode," page 96 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.
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 110).
d. Clean the exchanger as described in this manual if nec-
essary.
Model Shutdown
WM97+ flame signal
155 150
155HA 150
NOTE: "HA" means high altitude,
5500 feet or more above seal level.
– 97 –