Lochinvar Shield SNA285-125 - Manual (Page 36)

36
Failure to apply pipe sealing compound as
detailed in this manual can result in severe
personal injury, death, or substantial
property damage.
Shield water heaters are typically shipped
ready to fire on natural gas. Check the
water heater rating plate to determine
which fuel the water heater is set for. In
order to operate on LP gas contact the
factory, 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.
Use two wrenches when tightening gas
piping at water heater (FIG. 7-3), using
one wrench to prevent the water heater
gas line connection from turning. Failure
to support the water heater gas connection
pipe to prevent it from turning could
damage gas line components.
USE BACK UP WRENCH
TO PREVENT PIPE FROM
ROTATING
Figure 7-3 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 water heater 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 0.50 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. with no flow (lockup) or
with water heater on.
• Minimum 4 inches w.c. with gas flowing (verify during
water heater startup).
2. Install 100% lockup gas pressure regulator in supply line if
inlet pressure can exceed 14 inches w.c. at any time. Adjust
lockup regulator for 14 inches w.c. 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. maximum pressure.
2. Pressure required at gas valve inlet pressure port:
• Maximum 14 inches w.c. with no flow (lockup) or with
water heater on.
• Minimum 8 inches w.c. with gas flowing (verify during
water heater startup).
Maximum inlet gas pressure must not
exceed the value specified. Minimum
value listed is for the purposes of input
adjustment.
ƽ WARNING
ƽ WARNING
ƽ WARNING
ƽ WARNING Shield water heaters are typically shipped
ready to fire on natural gas. Check water
heater rating plate to determine which fuel
the water heater is set for. In order to
operate on LP gas contact the factory, 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
ƽ WARNING Ensure that the high gas pressure
regulator is at least 10 feet upstream of
the appliance.
7
Gas connections
Installation & Service Manual TM