7Gas connections
Installation & Operation Manual
WARNING
WARNING
Failure to apply pipe sealing compound as detailed in this manual can result in severe personal injury, death, or substantial property damage.
Use two wrenches when tightening gas piping at boiler (FIG.
Natural gas:
Pipe sizing for natural gas
1.Refer to Table 7A for pipe length and diameter. Based on rated boiler input (divide by 1,000 to obtain cubic feet per hour).
a.Table 7A is only for natural gas with specific gravity 0.60 inches, with a pressure drop through the gas piping of 0.5 inches w.c.
b.For additional gas pipe sizing information, refer to ANSI Z223.1 (or B149.1 for Canadian installations).
Natural gas supply pressure requirements
Figure 7-4 Inlet Pipe with Backup Wrench
1.Pressure required at the gas valve inlet pressure port:
•Maximum 14 inches w.c. (3.5 kPa) with no flow (lockup) or with boiler on.
•Minimum 4 inches w.c. (.99 kPa) with gas flowing (verify during boiler startup).
2.Install 100% lockup gas pressure regulator in supply line if inlet pressure can exceed 14 inches w.c. (3.5 kPa) at any time. Adjust lockup regulator for 14 inches w.c. (3.5 kPa) maximum.
Propane Gas:
USE BACK UP WRENCH TO PREVENT PIPE FROM ROTATING
WARNING
Knight XL boilers are typically shipped ready to fire on natural gas. Check boiler rating plate to determine which fuel the boiler is set for. If set to natural gas, it may be converted to LP by installing an orifice or by making a gas valve adjustment (see pages 13 and 14). In order to operate on LP gas, an orifice MUST BE installed or a gas valve adjustment MUST BE made. Failure to comply could result in severe personal injury, death, or substantial property damage.
NOTICE | Maximum inlet gas pressure must not | |
exceed the value specified. Minimum | ||
| ||
| value listed is for the purposes of input | |
| adjustment. |
42 
Pipe sizing for propane gas
1.Contact gas supplier to size pipes, tanks, and 100% lockup gas pressure regulator.
Propane Supply Pressure Requirements
1.Adjust propane supply regulator provided by the gas supplier for 14 inches w.c. (3.2 kPa) maximum pressure.
2.Pressure required at gas valve inlet pressure port:
•Maximum 14 inches w.c. (3.2 kPa) with no flow (lockup) or with boiler on.
•Minimum 8 inches w.c. (1.9 kPa) with gas flowing (verify during boiler startup).
WARNING Ensure that the high gas pressure regulator is at least 10 feet (3 m) upstream of the
appliance.
