Weil-McLain Aqua Balance WMB-155 Manual page 13

W
TM
AquaBalance
4 Converting boiler to propane
Pipe sizing for propane gas
1. Contact propane gas supplier to size piping, tank and install
a 100% lockup gas pressure regulator, or to verify size and
condition of existing piping and equipment.
Natural and Propane supply pressure
requirements
Adjust propane supply regulator provided by gas supplier for 13"
w.c. maximum pressure.
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" w.c. with no flow (lockup) or with boiler on.
b. Minimum: 3.5" w.c. gas pressure, with gas flowing (verify
during boiler startup, while boiler is at high fire).
c. Nominal gas pressure: 11.0" w.c.
2. Install 100% lockup gas pressure regulator in supply
line if inlet pressure can exceed 13" w.c. at any time.
Adjust lockup regulator for 13" w.c. maximum.
3. After connecting propane gas line to boiler, and BEFORE
operating, check gas pressure. If gas pressure is not in the
range above, close manual gas valve and contact gas supplier
to correct the problem before attempting to start or operate
the boiler.
Installing venturi —
If boiler is already installed
electrical 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.
Verify proper venturi for gas type
The venturi(s) provided with the kit(s) are permanently marked
on labels to indicate gas type "NAT GAS" Natural gas or "LPG"
for Liquefied petroleum (propane) gas and supplier part number.
See Figure 8, page 12 for kit contents.
Figure 9 Natural gas venturi label information
Part number 550-100-305/0118
M -
ALL OUNT GAS FIRED WATER BOILER
— You must turn off
—
Boiler Manual
continued
Figure 10
Liquefied Petroleum (propane) gas venturi label
information
Front panel removal
A
1. Remove two (2) screws on the bottom flange of front panel,
out and lift up to remove the front panel.
2. Remove the one (1) screw holding control module in place
Figure 12, rotate the control module.
Figure 11
Removing front panel
A
Figure 12
Moving control module for access to gas valve
LEGEND for Figure 12
1 Control module
2
1
2 Gas valve
13