DF Series installation manual
8
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3.
GAS PIPING CONNECTIONS
(MAIN BURNER, PILOT AND VENTS)
For units installed indoors, bleed and vent
connections must be extended to the
outdoor in accordance with local codes.
Gas piping connections
Main gas piping
With a NPT
1
pipe
diameter of this size...
...Drill a hole of this size
in unit wall
Pipe length extended
outside control cabinet
¾"
1
⅛"
(29mm)
6" (152mm)
1"
1
⅜"
(35mm)
6" (152mm)
1 ½"
2" (51mm)
6" (152mm)
2"
2 ½" (64mm)
6" (152mm)
3"
3
⅝"
(92mm)
6" (152mm)
Pilot piping
½"
⅞"
(22mm)
6" (152mm)
Gas connection pipe size (NPT)
Capacity
Gas inlet
Gas inlet (2 psig)
and outlet
(½ psig)
Gas outlet (2 psig)
750 MBH and less
¾"
Use external gas regulator to reduce to ½ psig
From 751 to 1000 MBH
1"
From 1001 to 2500 MBH
1 ½"
1 ½"
1 ½"
From 2501 to 5000 MBH
2"
1 ½"
2"
5001 MBH and more
3"
2"
3"
Pilot, vent and bleed valve pipe size (NPT)
1,2
Capacity
Pilot line diameter
Vent diameter
Bleed valve
750 MBH and less
¼" aluminum tubing
Not required (2 x 2" Ø
openings are required
in cabinet for
ventilation)
¾"
From 751 to 1000 MBH
From 1001 to 2500 MBH
From 2501 to 5000 MBH
1"
5001 MBH and more
1 ½"
1
NPT: National pipe thread
2
This table is not intended for gas line sizing.
3
If gas pressure exceeds ½ psi (14" w.c.), a high pressure regulator capable of modulating in a ratio of 40:1 must be added
at the unit inlet in order to adequately regulate the pressure at low fire.
4
Bleed valve vent piping to the exterior must not be connected to other vents.
