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GAS SUPPLY CONNECTIONS
Gas piping must have a sediment trap ahead of the
heater gas controls, and a manual shut-off valve lo-
cated outside the heater jacket. All gas piping should
be tested after installation in accordance with local
codes.
Gas Inlet
Gas Valve
Heater Jacket
Union
Sediment Trap
CAUTION: The heater and its manual shut off valve
must be disconnected from the gas supply during any
pressure testing of that system at test pressures in
excess of 1/2 psig (3.45 KPA). Dissipate test pressure
in the gas supply line before reconnecting the heater
and its manual shut off valve to gas supply line.
FAILURE TO FOLLOW THIS PROCEDURE MAY
DAMAGE THE GAS VALVE. OVER PRESSURED
GAS VALVES ARE NOT COVERED BY WARRANTY.
The heater and its gas connections shall be leak tested
before placing the appliance in operation. Use soapy
water for leak test. Do NOT use open flame.
NOTE: Do not use teflon tape on gas line pipe thread.
A flexible sealant is recommended.
A minimum of 7" W.C. and a maximum of 14" W.C.
upstream pressure under load, and no load conditions
must be provided for natural gas or a minimum of 12"
W.C. and a maximum of 14" for propane gas.
GAS PRESSURE REGULATOR
The gas pressure regulator is present and sealed
at 4"W.C. for natural gas, and 11"W.C. for propane
gas. Between the gas valve and the burners is a 1/8"
pipe plug. The pressure at this point , taken with a
manometer, should be about 3.7"W.C. natural gas
and 10.5"W.C. propane gas. If an adjustment is
needed, remove seal and turn adjustment screw
clockwise
to increase pressure or counter-clockwise
to decrease pressure.
Gas Pressure Test
at Gas Valve
Gas Pressure Test at Heater
Gas Valve
Manual Shut
Off Valve
Gas Pressure
Test Upstream
Manometer
ROBERTSHAW VALVE
W. C. adjustment
HONEYWELL VALVE
W. C. adjustment
PIPE SIZING FOR GAS CONNECTIONS
MAXIMUM EQUIVALENT PIPE LENGTH
Natural Gas 1000BTU/FT
3
.60 Specific Gravity
@ 0.5" WC Pressure Drop
Propane Gas 2500BTU/FT
3
1.53 Specific Gravity
@ 0.5" WC Pressure Drop
MODEL
155B
1/2" 3/4" 1"
N P N P N P
15 35 60 145 200 500
Manual Shut-Off
Valve
Fig. # 8090.0
Fig. # 8149.0
Fig. # 8081.0
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