Install Instructions

Combination Gas Valves
WIRING TERMINALS
PRESSURE REGULATOR
ADJUSTMENT
(UNDER CAP SCREW)
INLET PRESSURE TAP
GAS CONTROL KNOB
PILOT OUTLET
OUTLET
PRESSURE TAP
Figure 3-5_M9 Gas Valve
Venting of Combination Gas Valves
The combination gas valve regulator used on all
mod els is equipped with an integral vent limiting
orifice. The vent limiter ensures that the volume
of gas emitted from the valve does not exceed the
maximum safe leak age rate allowed by agency
re quire ments. Com bi na tion gas valve/regulators
equipped with integral vent limiters are not re quired
to have vent or relief lines piped to the outdoors. A
dust cap is provided at the vent termination point
on the valve to prevent block age of the vent limiter
by foreign material. The com bi na tion gas valve
regulator with an integral vent limiter complies with
the safety code requirements of CSD-1, CF-190(a)
as shipped from the manufacturer with out the
in stal la tion of additional vent lines.
Two Stage Burner Control System
The 45,000 thru 260,000 Btu/hr boilers (M9) are
equipped with a two stage burner control system.
Each unit has a combination gas valve to control the gas supply to the
burners. The com bi na tion valve con sists of a gas regulator and two valve
seats to meet the requirements for redundant gas valves. The valve has a
gas control knob that must remain in the open po si tion at all times when
the appliance is in service. Each gas valve has pres sure taps located on the
inlet and outlet sides. Manifold pressure is adjusted using the regulator
located on the valve. The manifold pres sure is pre set at the factory and
adjustment is not usu al ly re quired. If the manifold pressure is to be
ad just ed, follow the “Gas Manifold Pressure Ad just ment Pro ce dure”, page
20 for proper adjustment.
3 Gas connections
22
Installation & Service Manual