Part number 550-142-058/0811
91
WM97+
gas
-
fired
water
boiler
—
Boiler Manual
Maintenance
(continued)
Be careful when handling the igniter not to damage the
igniter ceramic.
k. Clean the igniter if necessary. Discard and replace the
igniter if it is damaged or cannot be cleaned.
Handle the cover plate/venturi/burner assembly
carefully to avoid damage to the igniter or refrac-
tory. Place the assembly on a clean, flat surface
with the assembly on its side, as shown in Fig-
ure 90, page 92 part C and part D.
3. See Figure 90, page 92 part C.
a. Use a wide-blade putty knife (item 11) to gently pry
the refractory from the heat exchanger cover plate. The
refractory is attached with silicone adhesive and should
separate with a little pressure on the putty knife.
DO NOT gouge or crack the refractory. The re-
fractory is made of ceramic fiber materials. Read
the ceramic fiber WARNING on page 76 before
handling or disposing of ceramic fiber materials.
Inspecting and cleaning the burner
1. See Figure 90, page 92 part D.
a. Slide the refractory (item 12) over the burner and off.
Set the refractory aside where it will be kept clean and
protected from damage. If the refractory is damaged, it
must be discarded and replaced with a new one.
b. Remove the three #20 Torx screws (item 14) securing the
burner (item 10) to the cover plate. Set aside.
c. Remove the burner and its gasket (item 13).
d. Inspect the interior of the burner. Brush and vacuum
the interior if needed to remove lint or sediment. The
burner can also be cleaned by blowing air or nitrogen
from the inside out, or clean with a water spray from
inside the burner.
e. Inspect the burner exterior. It must be in good condition,
with no visible damage.
f. Inspect the burner gasket. If the gasket is damage, obtain
a new gasket before re-installing the burner.
Inspecting and cleaning the heat exchanger
1. Access the heat exchanger interior by following the previous
instructions.
2. See Figure 90, page 92 part E.
3. Use a strong light to visually inspect the interior of the heat
exchanger. Make sure the flueways (tubes) are clear and
unobstructed.
a. If soot or debris is present, obtain a fresh water hose
with sprayer.
4. Use a vacuum cleaner to remove any accumulation on the
heating surfaces. This includes removing any pieces of refrac-
tory than may have dropped into the exchanger.
DO NOT use any solvent when cleaning the ex-
changer.
5. If the vacuum cleaner is unable to clean completely, wash the
heating surfaces with clean, warm water.
a. Place a bucket under the boiler condensate drain con-
nection.
Cleaning the heat exchanger FLUE
SIDE or accessing the burner, when
required
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.
Tools required
1. Long-handled Torx driver, #20.
2. Phillips head screwdriver, #2.
3. Torque wrench.
4. Putty knife.
Before proceeding:
1. Shut down the boiler:
a. Follow “To Turn Off Gas to Appliance” instructions on
boiler and Lighting instructions. Close the boiler manual
gas valve.
2. Allow time for the boiler to cool to room temperature if it
has been firing.
3. Remove jacket front door by releasing the two clamps at the
bottom of the jacket door.
4. Lift the jacket door away from the boiler to remove.
Removing components to allow access
1. See Figure 90, page 92 part A to locate components referenced
in the following.
2. See Figure 90, page 92 part B.
a. Pull the silencer straight forward until it snaps free of the
blower housing. Set the air silencer aside. Rotate the air
inlet silencer if needed to clear as it is removed.
b. Remove the gas valve retainer clip (item 4) and set aside.
Pull the gas valve slightly to the right until it disengages
from the venturi (item 5).
Support the gas valve. DO NOT allow it to hang
from the gas valve flex line. Make sure the gas valve-
to-venturi O-ring (item 5, Figure 10, page 13)
remains on the gas valve sleeve.
c. Disconnect the blower end of the gas valve sense line
(item 8).
d. Remove the blower retainer clip (item 15). Set aside.
e. Remove the four 10-mm hex nuts (item 9)that secure the
heat exchanger cover plate (item 6).
f. Disconnect the ground wire and electrode wire from the
igniter (item 7).
g. Remove the blower by pulling down. Disconnect the two
blower wiring harnesses on the back side of the blower.
h. Lift the cover plate/venturi/burner assembly vertically
until the refractory (part 3, item 12) clears the heat ex-
changer.
i. Tilt the cover plate/venturi/burner assembly slightly
forward. Then pull the assembly forward and out of the
jacket.
j. Remove the igniter by removing the two Phillips head
igniter screws. Set the igniter, its gasket and screws aside.