Desa VTN25R ES - Manual (Page 10)

www.desatech.com 113261-01A 10
INSTALLATION
Continued
CONNECTING TO GAS SUPPLY
WARNING: This appliance
requires a 3/8" NPT (National
Pipe Thread) inlet connection to
the pressure regulator.
WARNING: A qualified
service 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
(2.6 kPa) of water. If gas line pressure is higher,
heater regulator 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
(2.7 and 3.5 kPa) 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 12.
Pointing the vent down protects it from freezing
rain or sleet.
Figure 12 - External Regulator With Vent
Pointing Down
External
Regulator
Propane/LP
Supply Tank
Vent
Pointing
Down
CAUTION: Use only new,
black iron or steel pipe. Inter-
nally-tinned copper tubing may
be used in certain 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.
Typical Inlet Pipe Diameter
All 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 13,
page 11).
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.