Connecting To Gas Supply - Desa GN30 Safety Information And Installation Manual

INSTALLATION
Continued

CONNECTING TO GAS SUPPLY

WARNING: This appliance requires a 3/8" NPT
(National Pipe Thread) inlet connection to the pres-
sure regulator.
WARNING: A qualified service person must con-
nect heater to gas supply. Follow all local codes.
WARNING: For natural gas, never connect heater
to private (non-utility) gas wells. This gas is com-
monly known as wellhead gas.
IMPORTANT : For natural gas, check gas line pressure before
connecting heater to gas line. Gas line pressure must be no greater than
14 inches of water. If gas line pressure is higher, heater regulator
damage could occur.
CAUTION: For propane/LP gas, never connect
heater directly to the propane/LP supply. This heater
requires an external regulator (not supplied). Install
the external regulator between the heater and pro-
pane/LP supply.
For propane/LP gas, the installer must supply an external regulator.
The external regulator will reduce incoming gas pressure. You must
reduce incoming gas pressure to between 11 and 14 inches of water.
If you do not reduce incoming gas pressure, heater regulator damage
could occur. Install the external regulator with the vent pointing
down as shown in Figure 14. Pointing the vent down protects it from
freezing rain or sleet.
Propane/LP
Supply
Tank
Figure 14 - External Regulator With Vent Pointing Down
CAUTION: Use only new, black iron or steel pipe.
Internally-tinned copper tubing may be used in cer-
tain areas. Check your local codes. Use pipe of large
enough diameter to allow proper gas volume to heater.
If pipe is too small, undue loss of volume will occur.
For more information, visit www.desatech.com
For more information, visit www.desatech.com
107884
External
Regulator
Test
Gauge
Con-
Vent
nection*
Pointing
Down
Connecting To Gas Supply
Typical Inlet Pipe Diameters
20,000 Btu/Hr Models - 3/8" or greater
30,000 Btu/Hr Models - 1/2" or greater
Installation must include equipment shutoff valve, union, and
plugged 1/8" NPT tap. Locate NPT tap within reach for test gauge
hook up. NPT tap must be upstream from heater (see Figure 15).
IMPORTANT: Install an equipment shutoff valve in an accessible
location. The equipment shutoff valve is for turning on or shutting
off the gas to the appliance.
Apply pipe joint sealant lightly to male NPT threads. This will
prevent excess sealant from going into pipe. Excess sealant in pipe
could result in clogged heater valves.
WARNING: Use pipe joint sealant that is resistant
to liquid petroleum (LP) gas.
Install sediment trap in supply line as shown in Figure 15. Locate
sediment trap where it is within reach for cleaning. Locate sediment
trap where trapped matter is not likely to freeze. A sediment trap
traps moisture and contaminants. This keeps them from going into
heater controls. If sediment trap is not installed or is installed wrong,
heater may not run properly.
IMPORTANT: Hold the pressure regulator with wrench when
connecting it to gas piping and/or fittings. Do not over tighten pipe
connection to regulator. The regulator body could be damaged.
Pressure
Regulator
3/8" NPT
Pipe Nipple
Tee Joint
Reducer
Bushing to
1/8" NPT
1/8" NPT
Plug Tap
Tee
Joint
Sediment
Pipe
Trap
Nipple
Cap
Figure 15 - Gas Connection
* A CSA design-certified equipment shutoff valve with 1/8" NPT
tap is an acceptable alternative to test gauge connection. Purchase
the optional CSA design-certified equipment shutoff valve from
your dealer. See Accessories, page 27.
INSTALLATION
11
11
Note: Burner
bracket not
shown for
clarity
Heater
Cabinet
Ground Joint Union
Equipment
Shutoff Valve *
Natural Gas
From Gas Meter
(5" W.C. to 10.5" W.C.
Pressure)
3"
Propane/LP
Minimum
From External
Regulator
(11" W.C. to 14" W.C.
Pressure)