Desa GA3700 - Manual (Page 14)

www.desatech.com 113109-01G 14
For propane/LP units, 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 re-
duce incoming gas pressure, heater regulator
damage could occur. Install external regulator
with the vent pointing down as shown in Figure
17. Pointing the vent down protects it from
freezing rain or sleet.
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
1/2" diameter or greater to allow
proper gas volume to fireplace.
If pipe is too small, undue loss
of volume will occur.
Installation must include an 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 fireplace (see
Figure 18).
IMPORTANT: Install equipment shutoff valve
in an accessible location. The equipment
shutoff valve is for turning on or shutting off
the gas to the appliance.
Check your building codes for any special
requirements for locating equipment shutoff
valve to fireplaces.
Figure 17 - External Regulator on
Propane/LP Supply Tank with Vent
Pointing Down
External
Regulator
Vent
Pointing
Down
Propane/LP
Supply Tank
INSTALLATION
Continued
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 fireplace valves. Never use
sealant on flare threads.
WARNING: Use pipe joint
sealant that is resistant to liquid
petroleum (LP) gas.
We recommend that you install a sediment
trap in supply line as shown in Figure 18.
Locate sediment trap where it is within reach
for cleaning. Install in piping system between
fuel supply and fireplace. Locate sediment
trap where trapped matter is not likely to
freeze. A sediment trap traps moisture and
contaminants. This keeps them from going
into fireplace gas controls. If sediment trap
is not installed or is installed wrong, fireplace
may not run properly.
Figure 18 - Gas Connection
* Purchase the optional CSA design-certified
equipment shutoff valve from your dealer.
** Minimum inlet pressure for purpose of input
adjustment.
Sediment Trap
CSA Design-Certified
Equipment Shutoff Valve
With 1/8" NPT Tap*
3" Minimum
Cap Pipe Tee
Nipple Joint
Natural Gas
From Gas Meter
(5" W.C.** to
10.5" W.C. Pressure)
Propane/LP
From External
Regulator
(11" W.C.** to
14" W.C.
Pressure)