Specifications

Part number 550-142-120/0113
WM97+ gas-fired water boiler — Boiler Manual
– 14 –
Converting boiler to propane — WM97+70/110
Prepare boiler for propane —
WM97+70/110 only
(if required)
Propane operation
ALL WM97+ boilers must be converted for
propane operation
.
Converting an existing natural gas-fired boiler
for propane
— For a boiler already installed, you
must turn off gas supply, turn off power and allow
boiler to cool before proceeding. You must also
completely test the boiler after conversion to verify
performance and start up the boiler following in-
structions beginning on page 87 of this manual.
Verify 70/110 propane gas orifice bushing —
See Figure 8. Verify when installing that the orifice
size marking is correct. Bushings will be stamped
as in illustration or with “3.85” for model 70 and
“4.45” for model 110.
Failure to comply could result in severe personal
injury, death or substantial property damage.
Installing propane orifice bushing —
WM97+70/110 only
If boiler is already installed — You must turn off elec-
trical 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.
1. Locate the propane orifice bushing from the propane conversion
kit bag.
2. Verify that the stamping on the orifice bushing is correct for the
model size (see Figure 8).
3. If the jacket front door is not already removed, remove it.
4. Locate the gas valve and venturi (see Figure 9).
5. Pull the gas valve retention ring (item 3, Figure 9) off of the gas
valve/venturi joint.
6. Carefully pull the gas valve to the right until it is free of the venturi.
Leave the pressure reference hose (item 4, Figure 9) connected at
both ends.
Figure 8 Propane gas orifice bushing identification
WM97+70 on left (may be stamped 3.85)
WM97+110 on right (may be stamped 4.45)
70
110
Figure 9 Gas valve and venturi
1 Gas valve
2 Venturi
3 Gas valve retention ring
4 Pressure reference hose — LEAVE CONNECTED AT BOTH
ENDS
Support the gas valve after disconnecting
it. DO NOT allow it to hang from the gas
valve flex line. When re-attaching the gas
valve, ensure the gas valve-to-venturi O-
ring (item 5, Figure 10, page 15) is in place
and in good condition. Inspect the gas valve
flex line to ensure it is undamaged and in
good condition.