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16
NATURAL
(Dia)
PROPANE (LP)
(Dia)
45,000
2
23,000
#43
#55
115,000
5
23,000
#43
#55
140,000
6
23,000
#43
#55
90,000
4
23,000
#43
#55
GAS ORIFICES
MAXIMUM
INPUT
(BTUH)
NUMBER
of
BURNERS
MAXIMUM
BTUH/BURNER
Heat Exchanger and Burner Orifice Specifications
NOTE:
Gas appliances located more than 2000 feet above sea level
must be derated 4% per 1000 feet of total elevation and that
variance in gas heating value and specific gravity require change
in manifold pressure to obtain rating, it is mandatory that the input
be adjusted at the installation site. All installations should be made
as outlined in the latest edition of the National Fuel Gas Code ANSI
Z223.1,section “Procedures To Be Followed To Place An Appliance
in Operation”. Refer also to the “User’s Information Manual”
supplied with the unit for additional information on the gas furnace.
Gas Supply And Manifold Check
Gas supply pressure and manifold pressure with the burners oper-
ating must be as specified on the rating plate.
Gas Inlet Pressure Check
Gas inlet pressure must be checked and adjusted in accordance to
the type of fuel being consumed.
With Power And Gas Off:
1. Connect a water manometer or adequate gauge to the
inlet pressure tap of the gas valve.
Inlet gas pressure can also be measured by removing the
cap from the dripleg and installing a predrilled cap with a
hose fitting.
With Power And Gas On:
2. Put unit into heating cycle and turn on all other gas
consuming appliances.
NATURAL
Min. 5.0" W.C., Max. 10.0" W.C.
PROPANE
Min. 11.0" W.C., Max. 14.0" W.C.
INLET GAS PRESSURE
NOTE:
Inlet Gas Pressure Must Not Exceed the Maximum Value
Shown.
If operating pressures differ from above, make necessary pressure
regulator adjustments, check piping size, etc., and/or consult with
local utility.
Manifold Pressure Check
The gas valve has a tapped opening to facilitate measurement of
the manifold pressure. A “U” Tube manometer having a scale range
from 0 to 12 inches of water should be used for this measure-
ment. The manifold pressure must be measured with the burners
operating.
1. With disconnect switch open, remove field connected
thermostat wire from terminal R, W1 and W2 on TB1.
Place jumper wire between R, W1 and W2 to engage high
stage heat. (note on 045 kbtu/hr units W2 is not used,
only jumper R to W1).
2. See Figure in input rating section for gas valve adjustment.
To adjust the pressure regulator, remove the adjustment screw or
cover on the gas valve. Turn out (counterclockwise) to decrease
pressure, turn in (clockwise) to increase pressure. Only small varia-
tions in gas flow should be made by means of the pressure regula-
tor adjustment. In no case should the final manifold pressure vary
more than plus or minus 0.3 inches water column from the speci-
fied nominal pressure. Any major changes in flow should be made
by changing the size of the burner orifices. The measured input
rate to the furnace must not exceed the rating specified on the
unit rating plate.
For natural gas, the high stage manifold pressure must be between
3.2 and 3.8 inches water column (3.5 nominal). Low stage mani-
fold pressure must be between 1.7 to 2.3 inches water column
(2.0 nominal).
3. To set low fire rate on 090, 115 and 140 kbtu/hr: Open
disconnect switch, and remove jumper from R to W2. To
set low fire manifold pressure, repeat steps above. Refer
to Figure in input rating section for location of high and
low stage adjustment.
For propane gas, the manifold pressure must be between 9.7 and
10.3 inches water column (10.0 nominal). Low stage manifold must
be between 5.7 and 6.3 inches water column (6.0 nominal).
Gas Input (Natural Gas Only) Check
It is the responsibility of the contractor to adjust the gas input to
the unit.
To measure the gas input use a gas meter and proceed as
follows:
1. Turn off gas supply to all other appliances except the unit.
2. With the unit operating, time the smallest dial on the
meter for one complete revolution. If this is a 2 cubic foot
dial, divide the seconds by 2; if it is a 1 cubic foot dial, use
the seconds as is. This gives the seconds per cubic foot of
gas being delivered to the unit.
3. INPUT=GAS HTG VALUE x 3600 / SEC. PER CUBIC FOOT
Example:
Natural gas with a heating value of 1000 BTU per cubic
foot and 34 seconds per cubic foot as determined by Step 2, then:
Input = 1000 x 3600 / 34 = 106,000 BTU per Hour.
NOTE:
BTU content of the gas should be obtained from the gas
supplier. This measured input must not be greater than
shown on the unit rating plate.