Thomas & Betts BE User Manual
Form 436, Page 10
10. Gas Piping and Pressures
WARNING
This appliance is equipped for a maximum gas
supply pressure of 1/2 pound, 8 ounces, or 14
inches water column. Supply pressure higher
than 1/2 pound requires installation of an
additional service regulator external to the unit.
supply pressure of 1/2 pound, 8 ounces, or 14
inches water column. Supply pressure higher
than 1/2 pound requires installation of an
additional service regulator external to the unit.
PRESSURE TESTING SUPPLY PIPING
Test Pressures Above 1/2 PSI: Disconnect the heater and manual
valve from the gas supply line which is to be tested. Cap or
plug the supply line.
Test Pressures Below 1/2 PSI: Before testing, close the manual
valve from the gas supply line which is to be tested. Cap or
plug the supply line.
Test Pressures Below 1/2 PSI: Before testing, close the manual
valve on the heater.
All piping must be in accordance with requirements outlined in the
National Fuel Gas Code ANSI/Z223.1a (latest edition), published by
the American Gas Association or CAN/CGA-B149.1 and B149.2, pub-
lished by the Canadian Gas Association (See Paragraph 1). Gas supply
piping installation should conform with good practice and with local
codes.
National Fuel Gas Code ANSI/Z223.1a (latest edition), published by
the American Gas Association or CAN/CGA-B149.1 and B149.2, pub-
lished by the Canadian Gas Association (See Paragraph 1). Gas supply
piping installation should conform with good practice and with local
codes.
Unit heaters for natural gas are orificed for operation with gas having a
heating value of 1000 (+ or - 50) BTUH per cubic ft. If the gas at the
installation does not meet this specification, consult the factory for
proper orificing.
heating value of 1000 (+ or - 50) BTUH per cubic ft. If the gas at the
installation does not meet this specification, consult the factory for
proper orificing.
Pipe joint compounds (pipe dope) shall be resistant to the action of
liquefied petroleum gas or any other chemical constituents of the
gas being supplied.
liquefied petroleum gas or any other chemical constituents of the
gas being supplied.
Install a ground joint union and manual shut-off valve upstream of the
unit control system, as shown in Figure 8. The 1/8" plugged tapping in
the shut-off valve provides connection for supply line pressure test
gauge. The National Fuel Gas Code requires the installation of a trap
with a minimum 3" drip leg. Local codes may require a minimum drip
leg longer than 3" (typically 6").
unit control system, as shown in Figure 8. The 1/8" plugged tapping in
the shut-off valve provides connection for supply line pressure test
gauge. The National Fuel Gas Code requires the installation of a trap
with a minimum 3" drip leg. Local codes may require a minimum drip
leg longer than 3" (typically 6").
Gas connection sizes are included in the Dimensional Tables in Para-
graph 3. After all connections are made, disconnect the pilot supply at
the control valve and bleed the system of air. Reconnect the pilot line
and leak-test all connections by brushing on a soap solution.
graph 3. After all connections are made, disconnect the pilot supply at
the control valve and bleed the system of air. Reconnect the pilot line
and leak-test all connections by brushing on a soap solution.
Figure 8 - Supply
Piping Connection
Piping Connection
WARNING: All components of a gas supply
system must be leak tested prior to placing
equipment in service. NEVER TEST FOR
LEAKS WITH AN OPEN FLAME. Failure to
comply could result in personal injury, property
damage or death.
system must be leak tested prior to placing
equipment in service. NEVER TEST FOR
LEAKS WITH AN OPEN FLAME. Failure to
comply could result in personal injury, property
damage or death.
Manifold or Orifice Pressure Settings
Measuring manifold gas pressure cannot be done until the heater is in
operation. It is included in the steps of the "Check-Test-Start" proce-
dure in Paragraph 24. The following warnings and instructions apply.
operation. It is included in the steps of the "Check-Test-Start" proce-
dure in Paragraph 24. The following warnings and instructions apply.
WARNING: Manifold gas pressure must never
exceed 3.5" w.c. for natural gas and 10" w.c. for
propane gas.
exceed 3.5" w.c. for natural gas and 10" w.c. for
propane gas.
For Natural Gas: Manifold gas pressure is regulated by the combina-
tion valve to 3.5" w.c. Inlet pressure to the valve must be a minimum of
5" w.c. or as noted on the rating plate and a maximum of 14" w.c.
tion valve to 3.5" w.c. Inlet pressure to the valve must be a minimum of
5" w.c. or as noted on the rating plate and a maximum of 14" w.c.
For Propane Gas: Manifold gas pressure is regulated by the combina-
tion valve to 10" w.c. Inlet pressure to the valve must be a minimum of
11" w.c. and a maximum of 14" w.c.
tion valve to 10" w.c. Inlet pressure to the valve must be a minimum of
11" w.c. and a maximum of 14" w.c.
Sizing a Gas Supply Line
C a pa c i ty o f P i pi n g
C u b ic F e e t p e r H o u r b a s e d o n 0 .3 " w .c . P r e s s u r e D r o p
S p e c if ic G r a v it y f o r N a t u r a l G a s - - 0 .6 ( N a t u r a l G a s - - 1 0 0 0 B T U /C u b ic F t )
S p e c if ic G r a v it y f o r P r o p a n e G a s - - 1 .6 ( P r o p a n e G a s - - 2 5 5 0 B T U /C u b ic F t )
L e n g t h
D ia m e t e r o f P ip e
o f 1 / 2 "
3 / 4 "
1 "
1 -1 / 4 "
1 -1 / 2 "
2 "
P ip e
N a t u ra l P ro p a n e N a t u ra l P ro p a n e N a t u ra l P ro p a n e N a t u ra l P ro p a n e N a t u ra l P ro p a n e N a t u ra l P ro p a n e
2 0 '
9 2
5 6
1 9 0
1 1 6
3 5 0
2 1 4
7 3 0
4 4 5
1 1 0 0
6 7 1
2 1 0 0
1 2 8 1
3 0 '
7 3
4 5
1 5 2
9 3
2 8 5
1 7 4
5 9 0
3 6 0
8 9 0
5 4 3
1 6 5 0
1 0 0 7
4 0 '
6 3
3 8
1 3 0
7 9
2 4 5
1 4 9
5 0 0
3 0 5
7 6 0
4 6 4
1 4 5 0
8 8 5
5 0 '
5 6
3 4
1 1 5
7 0
2 1 5
1 3 1
4 4 0
2 6 8
6 7 0
4 0 9
1 2 7 0
7 7 5
6 0 '
5 0
3 1
1 0 5
6 4
1 9 5
1 1 9
4 0 0
2 4 4
6 1 0
3 7 2
1 1 0 5
6 7 4
7 0 '
4 6
2 8
9 6
5 9
1 8 0
1 1 0
3 7 0
2 2 6
5 6 0
3 4 2
1 0 5 0
6 4 1
8 0 '
4 3
2 6
9 0
5 5
1 7 0
1 0 4
3 5 0
2 1 4
5 3 0
3 2 3
9 9 0
6 0 4
9 0 '
4 0
2 4
8 4
5 1
1 6 0
9 8
3 2 0
1 9 5
4 9 0
2 9 9
9 3 0
5 6 7
1 0 0 '
3 8
2 3
7 9
4 8
1 5 0
9 2
3 0 5
1 8 6
4 6 0
2 8 1
8 7 0
5 3 1
1 2 5 '
3 4
2 1
7 2
4 4
1 3 0
7 9
2 7 5
1 6 8
4 1 0
2 5 0
7 8 0
4 7 6
1 5 0 '
3 1
1 9
6 4
3 9
1 2 0
7 3
2 5 0
1 5 3
3 8 0
2 3 2
7 1 0
4 3 3
1 7 5 '
2 8
1 7
5 9
3 6
1 1 0
6 7
2 2 5
1 3 7
3 5 0
2 1 4
6 5 0
3 9 7
2 0 0 '
2 6
1 6
5 5
3 4
1 0 0
6 1
2 1 0
1 2 8
3 2 0
1 9 5
6 1 0
3 7 2
N o t e : W h e n s iz in g s u p p ly lin e s , c o n s id e r p o s s ib ilit ie s o f f u t u r e e xp a n s io n a n d in c r e a s e d r e q u ir e m e n t s .
R e f e r t o N a t io n a l F u e l G a s C o d e f o r a d d it io n a l in f o r m a t io n o n lin e s iz in g.