Part number 550-142-058/0811
WM97+
gas
-
fired
water
boiler
—
Boiler Manual
44
Gas piping
WM97+ boilers are shipped ready to fire natural gas
ONLY. You must install the propane orifice bushing if
the boiler will be connected to propane. See page 12.
Failure to comply could result in severe personal injury,
death or substantial property damage.
Connecting gas supply piping
1. Remove jacket front panel and refer to Figure 49 to pipe gas to
boiler.
a. Place a pipe wrench on the gas line inside the jacket when
tightening the gas line assembly to the boiler gas connection
(item 1).
b. Install steel pipe fittings and factory-supplied gas cock as shown
in Figure 49. All pipe fittings are supplied by the installer. The
gas cock is shipped loose with the boiler.
c. In Canada — The gas shut-off valve (item 2) must be identi-
fied by the installer.
2. Use pipe dope compatible with propane gases. Apply sparingly
only to male threads of pipe joints so that pipe dope does not
block gas flow.
Failure to apply pipe dope as detailed above can result
in severe personal injury, death or substantial property
damage.
3. Connect gas supply piping to the ½” NPT gas cock (item 2).
4. Support gas piping with hangers, not by boiler or its accessories.
5. Purge all air from gas supply piping.
6. Before placing boiler in operation, check boiler and its gas con-
nection for leaks.
a. During any pressure testing at less than 13” (330 mm) w.c.,
close the gas shutoff valve and disconnect system gas piping.
At higher test pressures, disconnect boiler and gas valve from
gas supply piping.
Do not check for gas leaks with an open flame — use
bubble test. Failure to use bubble test or check for gas
leaks can cause severe personal injury, death or substan-
tial property damage.
DO NOT adjust or attempt to measure gas valve outlet
pressure. The gas valve is factory-set for the correct out-
let pressure. This setting is suitable for natural gas and
propane. Attempting to alter or measure the gas valve
outlet pressure could result in damage to the valve, caus-
ing potential severe personal injury, death or substantial
property damage.
Gas pipe sizing
1. See page 14 for gas line sizing information.
Check gas pressure at inlet to boiler
1. See Figure 76, page 73 for location of the gas inlet pressure test port.
Use two wrenches
when tightening gas
piping at boiler, using one wrench to pre-
vent the boiler gas line connection from
turning. Failure to support the boiler gas
connection pipe to prevent it from turn-
ing could damage gas line components.
Figure 49
Connect gas supply piping
1 Boiler gas supply connection, ½” NPT male
2 T-handle gas cock, ½” NPT, shipped loose with boiler
ALL OF THE FOLLOWING ARE SUPPLIED BY THE INSTALLER
3 Nipple, ½” NPT
4 Union, ½” NPT
5 Nipple, ½” NPT
6 Tee, ½” NPT
7 Nipple, ½” NPT x 4”, for drip leg
8 Cap, ½” NPT
2. For natural gas or propane, the pressure required at gas
valve inlet pressure port (verify minimum gas pressure
when all gas appliances are in operation):
a. Maximum: 13” (330 mm) w.c. with no flow (lockup)
or with boiler on.
b. Minimum gas pressure, with gas flowing (verify
during boiler startup, while boiler is at high fire)
— WM97+70: 3½” (89 mm) w.c.; WM97+110: 4½”
(114 mm) w.c.
3. Install 100% lockup gas pressure regulator in supply
line if inlet pressure can exceed 13” (330 mm) w.c. at
any time. Adjust lockup regulator for 13” (330 mm)
w.c. maximum.
