Raypak RAYTHERM 0133-4001 - Manual (Page 16)

A minimum of 7" W.C. and a maximum of 10.5" W.C. upstream pressure, under load and no-load conditions,
must be provided for natural gas, or a minimum of 12" W.C. and a maximum of 13" for propane.
Bleed Line Connection
GAS PRESSURE REGULATOR
The gas pressure regulator is preset nominally at 4" W.C. for natural gas, and 11" W.C. for propane. Between
the gas valve and the burners is a 1/8" pipe plug. The pressure at this point, taken with a manometer, should
be about 3.7" W.C. for natural gas and 10.5" W.C. for propane. Low NOx models should be 3.9" W.C., natural
gas only. If an adjustment is needed, turn adjustment screw clockwise to increase pressure, or counter-clockwise
to decrease pressure.
For boilers with mechanical modulation gas valves (Type H1 and H5) or two-stage gas valves (Type H3),
the gas pressure regulator is preset and sealed, and not field adjustable. Pressure tap is provided on the outlet
side of the gas valve for measurement of gas pressure in the manifold.
VENTING OF DIAPHRAGM GAS COMPONENTS
Gas valves that are equipped with a gas bleed must be vented to the outdoors as required by the National
Fuel Gas Code. Under NO circumstances shall bleed lines terminate in the gas utilization equipment flue or
exhaust system.
Fig. # 8185.2
16
GENERAL
Boiler should be located so that any water leaks will not cause damage to any adjacent areas or structures.
See piping diagrams for proper water connections for the type of boiler and system.
*Low NOx units not available for propane.