Raypak RAYTHERM 133-4001 - Manual (Page 17)

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Table G: Maximum Equivalent Pipe Length
A minimum of 7" W.C. and a maximum of 10.5" W.C.
upstream pressure, under load and no-load condi-
tions, must be provided for natural gas, or a minimum
of 12" W.C. and a maximum of 13" for propane.
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 manome-
ter, 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 need-
ed, 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.
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.
Pump Selection
In order to ensure proper hydraulics in your hydronic
heating system, adequate pump size must be select-
ed. We recommend that the pump be sized for 20°F
Delta T whenever possible. (Delta T is the temperature
Fig. 23: Bleed Line Connection Location
CAUTION: The boiler and its manual shut-off valve
must be disconnected from the gas supply during
any pressure testing of that system at test pressures
in excess of 1/2 PSIG. Dissipate test pressure in
the gas supply line before reconnecting the boiler
and its manual shut-off valve to gas supply line.
FAILURE TO FOLLOW THIS PROCEDURE MAY
DAMAGE THE GAS VALVE. OVER PRESSURED
GAS VALVES ARE NOT COVERED BY
WARRANTY. The boiler and its gas connections
shall be leak tested before placing the appliance in
operation. Use soapy water for leak test do NOT use
open flame.
*Low NOx units not available for propane.
Bleed Line
Connection
Vent Line
Connection