Installation – Desa WMN20A User Manual

Page 12

Advertising
background image

www.desatech.com

124002-01C

12

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" 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 regu-

lator (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" of water. If you do not reduce incom-
ing 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.

INsTallaTIoN

Continued

Figure 14 - External Regulator With Vent

Pointing Down

External
Regulator
With Vent
Pointing
Down

Propane/LP
Supply Tank

CAUTION: Use only new, black

iron or steel pipe. Internally-tinned

copper tubing may be used in

certain areas. Check your local

codes. Use pipe of large enough

diameter to allow proper gas vol-

ume to heater. If pipe is too small,

undue loss of volume will occur.

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 equip-
ment 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 mois-
ture 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.

Advertising
This manual is related to the following products: