Gas connections, Natural gas, Propane gas – Lochinvar Kight XL 400-801 User Manual
Page 25

25
4
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. 4-4), 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
IMG00420
Figure 4-4 Inlet Pipe with Backup Wrench
Natural gas:
Pipe sizing for natural gas
1. Refer to Table 4A for pipe length and diameter. Based on
rated boiler input (divide by 1,000 to obtain cubic feet per 
hour).
a. Table 4A is only for natural gas with specifi c 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
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.
ƽ WARNING
ƽ WARNING
NOTICE
ƽ WARNING
Ensure that the high gas pressure regulator 
is at least 10 feet (3 m) upstream of the 
appliance.
ƽ WARNING
Outdoor 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 page 12). 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.
Outdoor Knight XL Installation & Operation
Manual
