38
SYSTEM OPERATION
Ton
High Fire
Rate
Number
of
Burners
NG
Orifice LP Orifice
45,000
2
43
55
70,000
3
43
55
115,000
6
45
56
70,000
3
43
55
115,000
5
43
55
140,000
6
43
55
70,000
3
43
55
115,000
5
43
55
140,000
6
41
55
70,000
3
43
55
125,000
5
41
54
150,000
6
41
54
3
4
5
6
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 operating 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 manometer 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. 13.0" W.C.
INLET GAS PRESSURE
NOTE: Inlet gas pressure must be within limits shown
above.
If operating pressures differ from above, make necessary
pressure regulator adjustments, check piping size, etc.,
and/or consult with local utility.
Manifold Pressure Check and Adjustment
The gas valve has a pressure tap to facilitate measurement
of the manifold pressure. 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.
2. See Figure in gas input check section for gas valve
adjustment.
To adjust the pressure regulator, remove the adjustment
screw cover on the gas valve. Turn the adustment screw
out (counterclockwise) to decrease pressure, turn in
(clockwise) to increase pressure. Only small variations
in gas flow should be made by means of the pressure
regulator adjustment. 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 nom inal).
Low stage manifold pressure must be between 1.7 to 2.3
inches water column (2.0 nominal).
3. To set low fire rate, open disconnect switch and
remove jumper from R to W2. To set low fire
manifold pressure, repeat steps above. Refer to
Figure in gas input check section for location of high
and low stage pressure 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).
Summary of Contents for DRG0361DL00001S
Page 20: ...20 SYSTEM OPERATION...
