*Low NOx units not available for propane.
Table G: Maximum Equivalent Pipe Length
CAUTION: The boiler and its manual
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.
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.
Bleed Line
Connection
A minimum of 7" W.C. and a maximum of 10.5" W.C. upstream pressure, under load and
Vent 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 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
For boilers with mechanical modulation gas valves (Type H1 and H5) or
Fig. 23: Bleed Line Connection Location
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
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