State SBD85 500PE User Manual

Page 22

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 8. The figures

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.

(3.49 kPa) (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 fire 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.
taBle 8 - gas supply pipe length (feet)

Schedule 40 metallic

pipe nominal dia.

500,000 btu/hr input rate

MAXIMUM eQUIVAleNT PIPe leNGTh (FeeT)

Natural Gas

Propane

3/4"

1 1/4"

150

1 1/2"

150

350

200

400

2 1/2"

200

400

Natural Gas: 0.60 Specific Gravity, 0.50"W.C. pressure drop

Propane Gas: 1.50 Specific Gravity, 0.50"W.C. pressure drop

It is important to guard against gas valve fouling from contaminants

in the gas ways. Such fouling may cause improper operation, fire

or explosion.
If copper supply lines are used they must be internally tinned and

certified for gas service. Before attaching the gas line, be sure that

all gas pipe is clean on the inside.
To trap any dirt or foreign material in the gas supply line, a sediment

trap must be incorporated in the piping, see Figure 21. The

sediment trap must be readily accessible and not subject to freezing

conditions. Install in accordance with recommendations of serving

gas suppliers. refer to the current editions of the National Fuel

Gas Code or B149.1 Natural Gas and Propane installation code.
To prevent damage, care must be taken not to apply too much

torque when attaching gas supply pipe to gas valve inlet.
Apply joint compounds (pipe dope) sparingly and only to the

male threads of pipe joints. Do not apply compounds to the first

two threads. Use compounds resistant to the action of liquefied

petroleum gases.
gas meter siZe – natural gases only
Be sure the gas meter has sufficient capacity to supply the full

rated gas input of the water heater as well as the requirements of

all other gas fired equipment supplied by the meter. If gas meter

is too small, ask the gas company to install a larger meter having

adequate capacity.

supply gas regulator

The minimum gas supply pressure must not be less than 4.5" w.c.

(1.12 kPa) for Natural Gas or 11.0" w.c. (2.74 kPa) for propane.

Do not subject the gas valve to inlet gas pressures of more

than 14.0” W.C. (3.48 kPa). A supply gas regulator is necessary

if higher gas pressures are encountered. See Gas Pressure

requirements and Supply Gas regulator sections on page 12.
1. Supply gas regulators must be rated at or above the input Btu/

hr rating of the water heater they supply.

2. Supply gas regulators shall have inlet and outlet connections

not less than the minimum supply gas line size for the water

heater they supply. See Table 8.

gas piping and sediment trap installation

figure 21

gas line leak testing

Fire and Explosion Hazard

Use joint compound or Teflon tape

compatible with propane gas.

Leak test before placing the wateheater

in operation.

Disconnect gas piping and main gas

shutoff valve before leak testing.

Install sediment trap in accordance

with NFPA 54.

Any time work is done on the gas supply system perform a leak

test to avoid the possibility of fire or explosion.
1. For test pressures exceeding 1/2 psi (3.45 kPa) disconnect

the water heater and its Main Gas Shutoff Valve from the

gas supply piping system during testing, see Figure 21. The

gas supply line must be capped when disconnected from the

water heater.

2. For test pressures of 1/2 psi (3.45 kpa) or less, the appliance

need not be disconnected, but must be isolated from the

supply gas line by closing the Main Gas Shutoff Valve during

testing.

3. Coat all supply gas line joints and connections upstream of

the water heater with a non-corrosive soap and water solution

to test for leaks. Bubbles indicate a gas leak. Do not use

matches, candles, flame or other sources of ignition for this

purpose.

4. repair any leaks before placing the water heater in operation.

purging

Gas line purging is required with new piping or systems in which

air has entered.
Purging should be performed per the current edition of NFPA

54, the National Fuel Gas Code.

This manual is related to the following products:

SBD85 500NE