Weil-McLain Ultra Commercial Installation And Start-Up Manual page 10

COMMERCIAL GAS
Prepare boiler
Install propane orifice — Ultra-550 or -750
supply to the boiler and close the external manual gas shut-
off valve to isolate the boiler during conversion. Allow the
boiler to cool if it has been operating. Following conversion
of an installed boiler, follow all instructions in this manual
to start up the boiler and verify operation of the boiler and
all system components.
Ultra-550 boilers are shipped with a blower plate that is used
for natural gas and propane. The blower plate must be left in
place for propane applications.
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 4, page 11).
3. Remove jacket front door by rotating the two rotary latches.
4. Lift the door away from boiler.
5. See Figure 4, page 11.
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 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 result 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 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).
Ultra-750 propane only — Install the propane
blower plate and gaskets
1. See Figure 4, page 11.
2. Disconnect the two wire harnesses connected to the blower.
3. Ultra-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 oper-
ate the boiler on propane.
4. Obtain the two 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.
10
-
FIRED WATER BOILER
(continued)
— You must turn off electrical
— Boiler Manual
Legend for Figure 4, page 11
(see Figure 93, page 104 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 Ultra-750 natural gas, because
this unit does not use a blower plate — blower plate is
only used for the Ultra-750 propane. Ultra-550 boilers
use a plate for natural gas and propane (same plate is
used for both fuels).
4. Blower plate — used on all Ultra-550, natural gas and
propane; used on Ultra-750 propane only (not on
Ultra-750 natural gas).
5. Mixing tube.
6. Blower motor and blower.
7. Venturi — with gas line flange and inlet air connec-
tion.
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.
7. Disconnect the two 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 bolts through the mixing tube
flange.
12. Slide on the two 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
bolts.
15. Insert the remaining two bolts and fasten with nuts.
Be careful not to tear the gasket.
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 blower wiring harnesses.
Part number 550-100-086/0809