Desa CBN20T EN - Manual (Page 12)

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INSTALLATION
Continued
Figure 14 - External Regulator With
Vent Pointing Down
External
Regulator
Propane/LP
Supply Tank
Vent
Pointing
Down
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,
page 13).
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, page 13. 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.
CONNECTING TO GAS SUPPLY
WARNING: This appliance
requires a 3/8" NPT (National
Pipe Thread) inlet connection to
the pressure regulator.
WARNING: A qualified ser-
vice person must connect heater
to gas supply. Follow all local
codes.
WARNING: For natural
gas, never connect heater to
private (non-utility) gas wells.
This gas is commonly 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 10.5 inches of
water. If gas line pressure is higher, heater regula-
tor damage could occur.
CAUTION: For propane/LP
gas, never connect heater di-
rectly to the propane/LP supply.
This heater requires an external
regulator (not supplied). Install
the external regulator between the
heater and propane/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 pres-
sure, 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.