26
18-CD22D1-5
Installer’s Guide
UPFLOW – LEFT HAND GAS PIPING
UPFLOW – RIGHT HAND GAS PIPING
v
AUTOMATIC GAS VALVE
WITH MANUAL SHUTOFF
MAIN MANUAL
SHUTOFF VALVE
GROUND
UNION
JOINT
DRIP
LEG
AUTOMATIC GAS VALVE
WITH MANUAL SHUTOFF
MAIN MANUAL
SHUTOFF VALVE
GROUND
UNION
JOINT
DRIP
LEG
THE DOWNFLOW (VERTICAL) MAY BE INSTALLED LEFT OR RIGHT SIDE GAS PIPING
b
All gas fittings must be checked for leaks using a soapy
solution before lighting the furnace. DO NOT CHECK WITH
AN OPEN FLAME!
▲
CAUTION
!
Use a backup wrench on the gas valve when installing gas
piping to prevent damage to the gas valve and manifold
assembly.
TABLE 10
NATURAL GAS ONLY
TABLE OF CUBIC FEET PER HOUR OF GAS
FOR VARIOUS PIPE SIZES AND LENGTHS
PIPE
SIZE
LENGTH OF PIPE
10
20
30
40
50
60
70
1/2
132
92
73
63
56
50
46
3/4
278
190
152
130
115
105
96
1
520
350
285
245
215
195
180
1-1/4
1050
730
590
520
440
400
370
This table is based on pressure drop of 0.3 inch W.C. and 0.6 SP.GR. gas
Refer to piping Table 10, for delivery sizes. Connect gas supply
to the unit, using a ground joint union and a manual shut-off
valve as shown in Figures 34-36.
National codes require a condensation drip leg to be installed
ahead of the controls as shown in Figures 34-36.
The furnace and its individual shut-off valve must be discon-
nected from the gas supply piping system during any pressure
testing of that system at test pressures in excess of 1/2 psig
(3.5 kPa).
The furnace must be isolated from the gas supply piping by
closing its individual manual shut-off valve during any pressure
testing of the gas supply piping system at test pressures equal
to or less than 1/2 psig (3.5 kPa).
NOTE:
Maximum pressure to the gas valve for natural gas is
13.8" W.C. Minimum pressure is 5.0" W.C. Maximum pres-
sure to the gas valve for propane is 13.8" W.C.
Minimum pressure is 11.0" W.C.