Weil-McLain Evergreen EVG 220 Manual page 112

®
gas
Cleaning heat exchanger flue side
Inspect combustion chamber and
refractory
1. Look into the burner opening in the heat exchanger cover
plate.
2. Use a trouble light and inspection mirror to inspect the heat
exchanger interior.
a. Make sure that there is no debris inside the heat exchanger.
b. Use the inspection mirror to check the condition of the
burner refractory that is adhered to the bottom of the
heat exchanger cover plate. It must be in good condition
with no indication of damage or sagging.
c. Make sure there are no signs of overheating or of flue
gas leakage.
If visual inspection of the heat exchanger indicates
the need, follow the procedures in the following
to remove the heat exchanger cover plate and fully
inspect and clean the interior. Obtain replacement
parts for any components that may be damaged or
that show signs of leakage.
Remove components to access the
heat exchanger flue side
1. See Figure 109, page 115 part A to locate components refer-
enced in the following.
2. Remove the air silencer and disconnect gas line:
a. See Figure 109, page 115 part A and part B.
b. Locate the clips connecting the air silencer (item 1) to the
venturi (item 5). Gently pull clips out and away from the
venturi. While holding clips out, slide silencer back and
off of the venturi. Set the air silencer aside.
c. Disconnect the flexible gas line where it connects just
below the gas valve (item 3). Lay the free end of the flex-
ible gas line to the side.
Use two wrenches when disconnecting the
flexible gas line to prevent damage to the gas
valve and other gas line components.
d. Disconnect wire harness connected to the gas valve and
two wire harnesses connected to the blower.
3. Remove the blower/venturi/gas valve assembly.
a. See Figure 109, page 115, part A.
b. Remove the two (2) 8 mm locknuts connecting the blower
and cover plate.
c. Gently set blower/venturi/gas valve assembly aside. In-
spect blower/cover plate gasket. If gasket appears dam-
aged, discard and replace with a new gasket.
The burner, igniter and flame sense
rod must be removed and inspected
following the procedures beginning on
page 111.
– 112 –
-
fired water boiler
— 220/299/300/399 Boiler Manual
4. Remove the heat exchanger cover plate:
a. See Figure 109, page 115 part A, part B and part C.
b. Use a 10 mm wrench or socket to remove the nuts
(item 9) that secure the heat exchanger cover plate
(item 6) to the heat exchanger. [Six (6) nuts (EVG 220)
or seven (7) nuts (EVG 299/300/399).]
c. Carefully lift the cover plate assembly straight up vertically
until the cover plate refractory (part D, item 16) clears
the heat exchanger studs.
d. Pull the assembly forward and out of the jacket.
e. Turn the cover plate assembly over and place on a flat
surface.
Remove and discard refractory and
replace burner gasket
1. See Figure 109, page 115 part B and C.
a. Use a wide-blade putty knife to gently pry the refractory
from the heat exchanger cover plate. The refractory is at-
tached 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 94 before
handling or disposing of ceramic fiber materials.
b. Carefully scrape off any adhesive residue with the putty
knife, avoiding scratching or gouging the heat exchanger
cover plate surface.
c. Wipe off any residue, clean off the work table surface and
turn the cover plate over, bottom side on the work surface.
2. Remove the burner gasket (item 12) from the heat exchanger
cover plate.
3. Clean the gasket surface with a soft brush to remove any
gasket residue.
4. Lay the heat exchanger cover plate aside for re-installation
later.
Inspect and clean the heat exchanger
1. Remove and discard the heat exchanger cover plate gasket.
a. The Maintenance Kit includes a new gasket for use when
re-installing the cover plate.
b. Clean off any residue on the heat exchanger cover plate
gasket surface.
2. See Figure 109, page 115 part D.
3. Use a strong light to visually inspect the interior of the heat
exchanger. Make sure the flueways (tubes) are clear and
unobstructed.
4. Use a vacuum cleaner to remove any accumulation on the
heating surfaces. This includes removing any pieces of cover
plate insulation assembly than may have dropped into the
exchanger.
DO NOT use any solvent when cleaning the heat-
exchanger.
(continued)
Part number 550-100-131/0120