Natural Gas; Pipe Sizing For Natural Gas; Natural Gas Supply Pressure Requirements; Propane Gas - Lochinvar 400 Installation & Operation Manual

7
Gas connections
Failure to apply pipe sealing compound
WARNING
as detailed in this manual can result in
severe personal injury, death, or
substantial property damage.
Use two wrenches when tightening gas
WARNING
piping at boiler (FIG. 7-4), using one
wrench to prevent the boiler gas line
connection from turning.
support the boiler gas connection pipe
to prevent it from turning could damage
gas line components.
Figure 7-4 Inlet Pipe with Backup Wrench
USE BACK UP WRENCH TO
PREVENT PIPE FROM ROTATING
Maximum inlet gas pressure must not
NOTICE
exceed the value specified. Minimum
value listed is for the purposes of input
adjustment.
(continued)

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.
Failure to
b.

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 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:

WARNING

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
Installation & Operation Manual
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.
For additional gas pipe sizing information, refer to
ANSI Z223.1 (or B149.1 for Canadian installations).
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.
comply could result in severe personal
injury, death, or substantial property
damage.
Ensure that the high gas pressure regulator
is at least 10 feet (3 m) upstream of the
appliance.
Failure to
47