Warning, Caution – Goodman Mfg GAS-FIRED WARM AIR FURNACE GKS9 User Manual
Page 25
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Natural Gas Capacity of Pipe
In Cubic Feet of Gas Per Hour (CFH)
Length of
Nominal Black Pipe Size
Pipe in Feet
1/2"
3/4"
1"
1 1/4"
1 1/2"
10
132
278
520
1050
1600
20
92
190
350
730
1100
30
73
152
285
590
980
40
63
130
245
500
760
50
56
115
215
440
670
60
50
105
195
400
610
70
46
96
180
370
560
80
43
90
170
350
530
90
40
84
160
320
490
100
38
79
150
305
460
(Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based on
0.60 Specific Gravity Gas)
CFH =
BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
To connect the furnace to the building’s gas piping, the installer
must supply a ground joint union, drip leg, manual shutoff valve,
and line and fittings to connect to gas valve. In some cases, the
installer may also need to supply a transition piece from 1/2" pipe
to a larger pipe size.
The following stipulations apply when connecting gas piping. Re-
fer to Gas Piping Connections figure for typical gas line connec-
tions to the furnace.
•
Use black iron or steel pipe and fittings for building piping.
Where possible, use new pipe that is properly chamfered,
reamed, and free of burrs and chips. If old pipe is used, be
sure it is clean and free of rust, scale, burrs, chips, and old
pipe joint compound.
•
Use pipe joint compound on male threads ONLY. Always
use pipe joint compound (pipe dope) that is APPROVED
FOR ALL GASSES. DO NOT apply compound to the first two
threads.
•
Use ground joint unions.
•
Install a drip leg to trap dirt and moisture before it can enter
the gas valve. The drip leg must be a minimum of three
inches long.
•
Install a 1/8" NPT pipe plug fitting, accessible for test gage
connection, immediately upstream of the gas supply
connection to the furnace.
•
Always use a back-up wrench when making the connection
to the gas valve to keep it from turning. The orientation of
the gas valve on the manifold must be maintained as
shipped from the factory. Maximum torque for the gas valve
connection is 375 in-lbs; excessive over-tightening may
damage the gas valve.
•
Install a manual shutoff valve between the gas meter and
unit within six feet of the unit. If a union is installed, the
union must be downstream of the manual shutoff valve,
between the shutoff valve and the furnace.
•
Tighten all joints securely.
Refer to the National Fuel Gas Code, ANSI Z223.1, and information
provided by the gas supplier to determine the proper orifice size.
A different pressure switch may be required at high altitude regard-
less of the BTU/ft
3
content of the fuel used. Contact your distributor
for a tabular listing of appropriate altitude ranges and correspond-
ing manufacturer’s pressure switch kits.
P
ROPANE
G
AS
C
ONVERSION
P
OSSIBLE
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
MAY
OCCUR
IF
THE
CORRECT
CONVERSION
KITS
ARE
NOT
INSTALLED
. T
HE
APPROPRIATE
KITS
MUST
BE
APPLIED
TO
ENSURE
SAFE
AND
PROPER
FURNACE
OPERATION
. A
LL
CONVERSIONS
MUST
BE
PERFORMED
BY
A
QUALIFIED
INSTALLER
OR
SERVICE
AGENCY
.
WARNING
This unit is configured for natural gas. The appropriate
manufacturer’s propane gas conversion kit, must be applied for
propane gas installations. Refer to the Section VIII, Propane Gas
/ High Altitude Installations section for details.
G
AS
V
ALVE
This unit is equipped with a 24 volt gas valve controlled during
furnace operation by the integrated control module. As shipped,
the valve is configured for natural gas. The valve is field convertible
for use with propane gas by replacing the regulator spring with a
propane gas spring from an appropriate manufacturer’s propane
gas conversion kit. Taps for measuring the gas supply pressure
and manifold pressure are provided on the valve.
The gas valve has a manual ON/OFF control located on the valve
itself. This control may be set only to the “ON” or “OFF” position.
Refer to the lighting instructions label or Section XIV, Startup Pro-
cedure & Adjustment for use of this control during start up and shut
down periods.
G
AS
P
IPING
C
ONNECTIONS
G
ENERAL
T
O
AVOID
POSSIBLE
UNSATISFACTORY
OPERATION
OR
EQUIPMENT
DAMAGE
DUE
TO
UNDERFIRING
OR
EQUIPMENT
,
USE
THE
PROPER
SIZE
OF
NATURAL
/
PROPANE
GAS
PIPING
NEEDED
WHEN
RUNNING
PIPE
FROM
THE
METER
/
TANK
TO
THE
FURNACE
.
CAUTION
When sizing a trunk line, be sure to include all appliances which
will operate simultaneously when sizing a trunk line.
The gas piping supplying the furnace must be properly sized based
on the gas flow required, specific gravity of the gas, and length of
the run. The gas line installation must comply with local codes, or
in their absence, with the latest edition of the National Fuel Gas
Code, ANSI Z223.1.