MACH
®
Gas-Fired Boiler
Dual Fuel (NG & LP) MACH Boiler Supplement
6
2.2 F
UEL
S
ELECTION
1. Before switching fuels, ensure that the boiler is turned off.
2. Ensure that both fuel lines are correctly connected to the boiler.
3. Make sure the ball valve for the desired fuel is open.
4. Use the fuel selector switch, located inside the left control panel door near the top of the boiler, to select the
desired fuel. The fuel selector switch has three positions: propane, off and natural gas.
NOTICE!
The dual fuel selector switch is a hesitation type switch. When switching fuels you
must
release the switch in the “OFF” position before switching to the other fuel.
5. Start the boiler according to the MACH® C750-C1050 Installation & Owner’s Manual (latest edition)
NOTICE!
It is recommended to close the ball valve of the non-selected fuel.
FUEL SELECTOR SWITCH
2.3 G
AS
V
ALVE
A
DJUSTMENT
Open front door on the right side of the boiler. The two gas valves are located inside the cabinet on the left. Each
valve is labeled and adjusted for a specific fuel. The upper gas valve is for natural gas (NG). The lower gas valve is
for propane (LP). Check the combustion using a combustion analyzer and adjust the fuel/air ratio of the valve being
used according to the procedures outlined in the latest edition of the MACH® C750-C1050 Installation & Owner’s
Manual.
