Weil-McLain Evergreen EVG 70 Manual page 124

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Cleaning heat exchanger fl ue side, 155
DO NOT gouge or crack the refractory. The
refractory is made of ceramic fi ber materials. Read
the ceramic fi ber WARNING on page 101 before
handling or disposing of ceramic fi ber materials.
c. When replacing the refractory, apply a ring of silicone
adhesive on the cover plate. Place the refractory onto the
cover plate. Before handling the assembly, allow the adhesive
to set enough that the refractory is fi rmly held in place.
2. Clean the burner gasket surface inside the heat exchanger cover
plate (item 6) with a soft brush to remove any gasket residue.
3. The burner gasket must be replaced with a new one when the
boiler is re-assembled after servicing.
Inspect and clean the heat exchanger
1. Access the heat exchanger interior by following the previous
instructions. Remove and inspect the heat exchanger cover
plate gasket. Replace if necessary.
2. See Figure 108, page 125 part E.
3. Before using water to clean the heat exchanger, remove the
control module (item 17). Label wires if they are not labeled.
Set aside. Remove all connectors and wire harnesses from the
control module and then remove the two screws securing it to
the bracket.
4. Use a strong light to visually inspect the interior of the heat
exchanger. Make sure the flue ways (tubes) are clear and
unobstructed.
5. Use a vacuum cleaner to remove any accumulation on the heating
surfaces. This includes removing any pieces of refractory that
may have dropped into the exchanger.
DO NOT use any solvent when cleaning the
exchanger.
6. 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
connection.
b. Loosen and move the condensate bracket, then loosen
the condensate trap upper nut and slide the trap off
of the drain connection.
reference.)
c. Spray fresh water into the heat exchanger and tubes to
remove sediment. Collect water in the bucket below.
7. Inspect the heat exchanger cover plate gasket (item 18). Replace
if is damaged in any way.
Reinstall components
1. See Figure 108, page 125 for reference.
2. Reinstall the control module (item 20) to the control bracket
and reconnect all connectors and wire harnesses.
3. Reinstall the burner (item 11), burner gasket (item 12) and
burner access cover seal (item 13) on the heat exchanger cover
plate (item 6).
a. Insert and tighten the burner cover plate screws and
washers (item 10) using a Phillips screwdriver. The screws
must be secure, with torque no more than 20 inch-pounds.
4. Reinstall the heat exchanger cover plate assembly on the heat
exchanger.
a. Seat the heat exchanger cover plate gasket on the heat
exchanger sealing surface.
b. Tilt heat exchanger cover plate front lip downward until back lip
clears cabinet and burner can slide inside combustion chamber.
Slide cover plate back and rotate until seated fl at on the heat
124
as-fired water boiler —
(See Figure 56, page 52 for
Boiler Manual
70/110/155
Figure 105 Legend for Figure 108, page 125
Boiler interior
A
B Assembled heat exchanger
cover plate (item 6),
burner (item 11), showing
refractory (item 15)
C Disassembly of heat
exchanger cover plate,
burner and other
components
D Burner assembly
E Heat exchanger interior
1 Inlet air silencer
2 Blower assembly
3 Gas valve
4 Burner access cover
5 Venturi assembly
6 Heat exchanger cover plate
7 Igniter assembly
exchanger sealing surface. Avoid gouging the refractory on
the heat exchanger studs.
c. Secure the heat exchanger cover plate (item 6) to the heat
exchanger with the fi ve (5) M6 nuts using a 10mm wrench.
You must gradually tighten the cover plate nuts using
a torque wrench. The fi nal torque MUST NOT exceed
45 inch-pounds. Alternate tightening until all nuts
reach 45 inch-pounds.
5. Reinstall the blower/gas valve/venturi assembly (items 2, 3, and 5).
a. Place blower fl ange on to studs protruding from cover plate.
b. Reinstall the two (2) 5/16" locknuts using a socket with
extension.
c. Do not over tighten (torque no more than 20 inch-pounds).
6. Reinstall the igniter assembly (item 7).
a. The igniter gasket must be intact and in good condition.
Replace with a new gasket if necessary.
b. Insert the igniter into the cover plate opening, with the
gasket in position.
c. Reinstall the two (2) Socket head Allen bolts fi nger tight.
d. Use a torque wrench to tighten the igniter screws.
DO NOT exceed 25 inch-pounds torque.
e. Reconnect the ignition cable and the igniter ground wire.
7. Reconnect the fl exible gas line to the gas valve using two wrenches.
8. Reinstall the air inlet silencer (item 1) by pressing up onto the
venturi (item 5). Rotate the air silencer clip (item 8) and snap it
onto the gas line.
9. Reconnect the two (2) wire harnesses to the blower and gas valve.
10. Reinstall the condensate trap and bracket on the boiler
condensate drain connection. (See Figure 56, page 52 for
reference.)
Perform a complete start-up procedure when putting
the boiler back into service. See page 91 and all
instructions for start-up and verifi cation. Include a
soap suds leak test on all interior and exterior gas
piping after starting the boiler.
(continued)
8 Air silencer clip
9 Heat exchanger cover plate
retainer nuts, (5)
10 Burner cover retainer (3)
screws, M4 Phillips plus fl at
washers
11 Burner
12 Burner gasket
13 Burner access cover seal
14 Burner sealing surface
(lower surface of burner
fl ange)
15 Refractory
16 Cover plate gasket
17 Control module
18 Heat exchanger tube sheet
19 Heat exchanger outer shell
Part number 550-100-191/0917