Direct/Standard Inlet Piping; Indirect/Alternate Inlet Piping; Gas Piping Checks - Amana GUCA Installation Instructions Manual

Natural Gas Capacity of Pipe
In Cubic Feet of Gas Per Hour (CFH)
Length of
Pipe in Feet 1/2" 3/4"
10 132 278
20 92 190
30 73 152
40 63 130
50 56 115
60 50 105
70 46 96
80 43 90
90 40 84
100 38 79
(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 pip-
ing. Refer to the previous figures for typical gas line
connections to the furnace.
•
Use black iron or steel pipe and fittings for the building
piping.
•
Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
•
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.
•
Use two pipe wrenches when making 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.
•
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.
•
Connect the furnace to the building piping by one of the
following methods:
–
Rigid metallic pipe and fittings.
–
Semi-rigid metallic tubing and metallic fittings.
Aluminum alloy tubing must not be used in exterior
locations. In order to seal the grommet cabinet
penetration, rigid pipe must be used to reach the
outside of the cabinet. A semi-rigid connector to
the gas piping may be used from there.
•
Use listed gas appliance connectors in accordance
with their instructions. Connectors must be fully in the
same room as the furnace.
•
Protect connectors and semirigid tubing against physi-
cal and thermal damage when installed. Ensure alumi-
Nominal Black Pipe Size
1" 1 1/4"
520 1050
350 730
285 590
245 500
215 440
195 400
180 370
170 350
160 320
150 305
num-alloy tubing and connectors are coated to protect
against external corrosion when in contact with ma-
sonry, plaster, or insulation, or subjected to repeated
1 1/2"
wetting by liquids such as water (except rain water),
1600
detergents, or sewage.
1100
980
CAUTION
760
670
Edges of sheet metal holes may be sharp.
610
Use gloves as a precaution when removing
560
530
hole plugs.
490
460

Direct/Standard Inlet Piping

When gas piping enters directly to the gas valve through the
standard inlet hole, the installer must supply straight pipe
with a ground joint union to reach the exterior of the furnace.
The rigid pipe must be long enough to reach the outside of
the cabinet to seal the grommet cabinet penetration. A
semi-rigid connector to the gas piping can be used outside
the cabinet per local codes.

Indirect/Alternate Inlet Piping

When gas piping enters indirectly to the gas valve through
the alternate gas inlet hole the following fittings (starting
from the gas valve) to reach the outside of the cabinet must
be supplied:
•
Coupling.
•
90 degree elbow.
•
2 inch close nipple.
•
90 degree elbow.
•
Straight pipe, with a ground joint union, to reach the
exterior of the furnace. The rigid pipe must be long
enough to reach the outside of the cabinet so as to seal
the grommet cabinet penetration. A semi-rigid connec-
tor to the gas piping can be used outside the cabinet per
local codes.

Gas Piping Checks

Before placing unit in operation, leak test the unit and gas
connections.
WARNING
To avoid the possibility of explosion or fire,
never use a match or open flame to test for
leaks.
Check for leaks using an approved chloride-free soap and
water solution, an electronic combustible gas detector, or
other approved testing methods.
NOTE: Never exceed specified pressures for testing.
Higher pressure may damage the gas valve and cause
subsequent overfiring, resulting in heat exchanger failure.
Disconnect this unit and shutoff valve from the gas supply
piping system before pressure testing the supply piping
system with pressures in excess of 1/2 psig (3.48 kPa).
Isolate this unit from the gas supply piping system by
closing its external manual gas shutoff valve before pres-
sure testing supply piping system with test pressures equal
to or less than 1/2 psig (3.48 kPa).
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