Weil-McLain SlimFit 2 Series Manual page 9

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SlimFit
COMMERCIAL CONDENSING GAS
Prepare boiler
1. Locate propane orifice disc from conversion kit bag shipped
with the boiler.
2. Verify that the stamping on the orifice disk matches the model
size (see Figure 2, page 10).
3. Remove front door by rotating the two rotary latches.
4. Lift the door away from boiler.
5. See Figure 2, page 10.
6. Disconnect the gas train adapter flange (see item 12) from
the venturi gas line flange (see item 7):
a. Use a 4 mm Allen wrench and 8 mm open-end or box
wrench to loosen the four (4) screws and nuts (items 10
and 11).
b. Remove the gasket (item 9).
Inspect the gasket between the gas train adapter
flange (see item 12) and the venturi gas line flange
(see item 7). The gasket must be in good condition
and must be installed. Failure to comply could re-
sult in a gas leak, resulting in severe personal injury,
death or substantial property damage.
c. The gas train is connected with a flexible gas line. Pull the
gas train forward and support it temporarily.
d. Insert the propane orifice into the counterbore in the
venture flange.
e. Reposition the gasket and gas train adapter against the
venturi gas line flange.
f. Secure with the four (4) screws and nuts. Do not over-
tighten, but make sure the joint is secure (torque to
1.5 N-m/13 in-lbs/1 ft-lb).
SF-750 propane only — Install the
propane blower plate and gaskets
1. See Figure 2, page 10.
2. Disconnect the two wire harnesses connected to the blower.
3. SF-750 natural gas boilers do not use a blower plate. The
boiler is shipped with a blower plate and gaskets that must
be installed to operate the boiler on propane.
4. Obtain the two (2) gaskets (item 3) and blower plate (item 4)
shipped with the boiler.
5. Check the blower plate to ensure it says "750 LP."
6. Turn off all power sources to the boiler.
7. Disconnect the two (2) wiring connectors on the blower.
8. Disconnect the blower flange (see item 6) from the mixing
tube flange (see item 5) as shown.
9. Use a 13 mm nut driver or ratchet for the screws and a 13 mm
open-end wrench for the nuts.
10. Support the weight of the blower and gas train temporarily.
11. Insert the top two (2) bolts through the mixing tube flange.
12. Slide on the two (2) gaskets and blower plate, with one gasket
on each side as shown.
13. Position the blower.
14. Align all parts and start the nuts on the top two (2) bolts.
15. Insert the remaining two (2) bolts and fasten with nuts. Be
careful not to tear the gasket.
Part number 550-100-162/0815
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FIRED WATER BOILER
(continued)
—
Boiler Manual Series 2
16. Secure the flanges together with the bolts and nuts, being
careful not to over-tighten (torque to 15 N-m/132 in-
lbs/11 ft-lbs).
17. Reconnect the two (2) blower wiring harnesses.
18. Reinstall front door, and secure the latches.
19. Restore electrical power, turn on gas by opening manual gas
valve and check for leaks.
20. Follow instructions starting on page 80 to adjust combustion
values for propane gas.
21. Perform a complete start up sequence, starting on page 77,
including a check for gas leaks and confirming proper per-
formance.
22. After placing the boiler in operation, the ignition system safety
shutoff device must be tested, page 81.
Legend for Figure 2, page 10
(see Figure 96, page 110 for part numbers)
1. Hex bolts (4), M8 x 30 mm — requires 13 mm open-end wrench,
box wrench or ratchet.
2. Hex nuts (4), M8 keps — nylon lock nuts — requires 13 mm open-
end wrench, box wrench or ratchet.
3. Blower plate gasket (one on each side of blower plate). One gasket is
used on SF-750 natural gas, because this unit does not use a blower
plate — blower plate is only used for the SF-750 propane. SF-550
boilers use a plate for natural gas and propane (same plate is used
for both fuels).
4. Blower plate — used on all SF-550, natural gas and propane; used on
SF-750 propane only (not on SF-750 natural gas).
5. Mixing tube.
6. Blower motor and blower.
7. Venturi — with gas line flange and inlet air connection.
8. Propane orifice — shipped with boiler — verify the model number
stamped on the orifice.
9. Gasket — venturi gas flange to gas line adapter flange.
10. Hex nuts (4), M5 keps — requires 8 mm open-end or box wrench.
11. Hex bolts (4), M 5 x 20 mm — requires 4 mm Allen wrench.
12. Gas line adapter flange.
13. Manual gas valve.
14. Automatic gas valve.
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