Raypak 302B-902B - Manual (Page 21)

at test pressures equal to or less than 1/2 psi (3.45
kPa). Relieve test pressure in the gas supply line prior
to reconnecting the heater and its manual shut-off
valve to the gas supply line. FAILURE TO FOLLOW
THIS PROCEDURE MAY DAMAGE THE GAS
VALVES. Over pressurized gas valves are not cov-
ered 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
an open flame.
Reversing Gas Supply Connection
Reversing the standard fuel connection from the left-
hand to the right-hand side is a simple field operation.
1. Disconnect all electrical power from the heater (if
applicable).
2. Disconnect the main gas pipe from the heater (if
applicable).
3. Remove the left and right front panels from the
heater.
4. Locate the main gas line that traverses across the
heater above the manifold risers.
5. Remove the pipe cap from the right-hand end of
the main gas line.
21
Gas Supply
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. It is recommended
that a union be installed in the gas supply piping adja-
cent to the heater for servicing. A pounds-to-inches
regulator must be installed to reduce the gas supply
pressure to a maximum of 10.5 in. WC for natural gas
and 13.0 in. WC for propane gas. The regulator should
be placed a minimum distance of 10 times the pipe
diameter up-stream of the heater gas controls. Refer
to Table K for maximum pipe lengths.
Gas Supply Connection
The heater must be isolated from the gas supply pip-
ing system by closing the manual shut-off valve during
any pressure testing of the gas supply piping system
CAUTION: The heater must be disconnected from
the gas supply during any pressure testing of the gas
supply system at test pressures in excess of 1/2 psi
(3.45 kPa).
Fig. 16: Gas Supply Connection
CAUTION: Do not use Teflon tape on gas line pipe
thread. A pipe compound rated for use with natural
and propane gases is recommended. Apply
sparingly only on male pipe ends, leaving the two
end threads bare.
CAUTION: Support gas supply piping with
hangers, not by the heater or its accessories. Make
sure the gas piping is protected from physical
damage and freezing, where required.
3/4" 1” 1-1/4” 1-1/2” 2” 2-1/2” Model
No.
N P N P N P N P N P N P
302B 15 25 35 85 150 380 360 -- -- -- -- --
402B -- 15 25 60 100 260 250 -- -- -- -- --
502B -- -- -- -- 65 150 130 360 500 -- -- --
652B -- -- -- -- 45 100 95 250 340 -- -- --
752B -- -- -- -- 35 80 75 180 260 600 -- --
902B -- -- -- -- 20 45 45 110 150 360 400 --
Table K: Maximum Equivalent Pipe Length
DANGER: Make sure the gas on which the heater
will operate is the same type as specified on the
heater’s rating plate.
Natural gas – 1,000 BTU per ft 3 , .60 specific gravity at 0.5 in. WC pressure drop
Propane gas – 2,500 BTU per ft 3 , 1.53 specific gravity at 0.6 in. WC pressure drop