47
7
Gas connections
(continued)
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. 7-4), using one
wrench to prevent the boiler gas line
connection from turning. Failure to
support the boiler gas connection pipe
to prevent it from turning could damage
gas line components.
USE BACKUP WRENCH TO
PREVENT PIPE FROM ROTATING
Figure 7-4 Inlet Pipe with Backup Wrench
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 specifi c gravity
0.60 inches, with a pressure drop through the gas
piping of 0.3 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
1. Pressure required at the gas valve inlet pressure port:
• Maximum 14 inches w.c. (3.5 kPa) with no fl ow
(lockup) or with boiler on.
• Minimum 4 inches w.c. (.99 kPa) with gas fl owing (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:
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 fl ow (lockup)
or with boiler on.
• Minimum 8 inches w.c. (1.9 kPa) with gas fl owing (verify
during boiler startup).
Maximum inlet gas pressure must not
exceed the value specifi ed. Minimum
value listed is for the purposes of input
adjustment.
WARNING
WARNING
NOTICE
WARNING
Ensure that the high gas pressure regulator
is at least 10 feet (3 m) upstream of the
appliance.
Installation & Operation Manual
WARNING
Knight XL boilers are typically shipped
ready to fi re 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 orifi ce
or by making a gas valve adjustment (see
pages 13 and 14). In order to operate on LP
gas, an orifi ce 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.
