7
Servicing should only be performed by a Qualied Service Technician
GAS PIPING
Contact your local gas service company to ensure that adequate gas service is available and to review
applicable installation codes for your area.
Size the main gas line in accordance with Table below. The gures shown are for straight lengths of pipe
at 0.5 in. W.C. pressure drop, which is considered normal for low pressure systems. Note: Fittings such as
elbows, tees and line regulators will add to the pipe pressure drop. Also refer to the latest version of the
National Fuel Gas Code.
Schedule 40 Steel or Wrought Iron Pipe is the preferred material for the gas line of this water heater. It
is imperative to follow the sizing recommendations in the latest version of the National Fuel Gas Code if
Corrugated Stainless Steel Tubing (CSST) is used as the gas line for this water heater.
The heater is not intended for operation at higher than 14.0" W.C.- natural gas, (1/2 pound per square inch
gage) supply gas pressure. Exposure to higher supply pressure may cause damage to the gas valve which
could result in re or explosion. If overpressure has occurred such as through improper testing of gas lines or
emergency malfunction of the supply system, the gas valve must be checked for safe operation. Make sure
that the outside vents on the supply regulators and the safety vent valves are protected against blockage.
These are parts of the gas supply system, not the heater. Vent blockage may occur during ice storms.
GAS SUPPLY PIPE LENGTHS (IN FEET)
Maximum Equivalent Pipe Length - Natural Gas Only
Input rate
(BTU/HR)
Schedule 40 Steel or Wrought Iron Pipe
1/2" 3/4" 1" 1 1/4" 1 1/2"
120,000 20 70 200 200 200
154,000 10 40 150 200 200
180,000 - 30 100 200 200
199,000 - 30 90 200 200
250,000 - 20 60 200 200
275,000 - 10 50 200 200
310,000 - 10 40 150 200
366,000 - - 30 100 200
390,000 - - 20 100 200
Fitting Type* Equivalent length in feet
45°Ell 0.7 1.0 1.2 1.6 1.9
90°Ell 1.6 2.1 2.6 3.5 4.0
Tee 3.1 4.1 5.2 6.9 8.0
Natural Gas 0.60 Specic Gravity, 0.50" W.C. Pressure Drop
*Screwed Fittings
It is important to guard against gas valve fouling from contaminants in gas ways. Such fouling may cause
improper operation, re or explosion.
If copper supply lines are used they must be internally tinned and certied for gas service. Before attaching
the gas line, be sure that all gas pipe is clean on the inside. The instructions in this section on venting must
be followed to avoid choked combustion or recirculation of ue gases. Such conditions cause sooting or risks
of re and asphyxiation.
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