Measure Manifold Pressure (Propane Units)
The main burner orifices on a propane gas unit are sized for
the unit rated input when the manifold pressure reading
matches the level specified in Table 5.
Proceed as follows to adjust gas input on a propane gas unit:
1. Turn off gas to unit.
2. Remove pipe plug on manifold (see Fig. 24), then con-
nect manometer at this point.
3. Turn on gas to unit.
4. Remove cover screw over regulator adjustment screw on
gas valve.
5. Adjust regulator adjustment screw to the correct mani-
fold pressure, as specified in Table 5. Turn adjusting
screw clockwise to increase manifold pressure, or turn
adjusting screw counterclockwise to decrease manifold
pressure.
6. Replace cover screw.
7. Turn off gas to unit. Remove manometer from pressure
tap. Replace pipe plug on gas valve, then turn on gas to
unit. Check for leaks.
D. Check Burner Flame
With burner access panel removed, observe the unit heating
operation. Watch the burner flames to see if they are light
blue and soft in appearance, and that the flames are approxi-
mately the same for each burner. Propane will have blue flame
with yellow tips. See Fig. 25. Refer to Maintenance section
for information on burner removal.
E. Airflow and Temperature Rise
The heating section for each size unit is designed and ap-
proved for heating operation within the temperature-rise range
stamped on the unit rating plate.
Table 6 shows the approved temperature-rise range for each
heating input, and the air delivery cfm at various tempera-
ture rises. The heating operation airflow must produce a tem-
perature rise that falls within the approved range.
Refer to Indoor Airflow and Airflow Adjustments section on
page 35 to adjust heating airflow when required.
Table 6 — Air Delivery (Cfm) at Indicated Temperature Rise and Rated Heating Input
HEATING
INPUT
(Btuh)
TEMPERATURE RISE °F
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
40,000
1389
1111
926
794
694
617
556
—
—
—
—
—
—
—
—
56,000
2083
1667
1389
1190
1042
926
833
758
—
—
—
—
—
—
—
80,000
2778
2222
1852
1587
1389
1235
1111
1010
926
855
794
—
—
—
—
95,000
3472
2778
2315
1984
1736
1543
1389
1263
1157
1068
992
926
868
—
—
120,000
4167
3333
2778
2381
2083
1852
1667
1515
1389
1282
1190
1111
1042
980
926
136,000
5037
4029
3358
2878
2518
2238
2014
1831
1679
1549
1439
1343
1259
1185
1119
NOTE: Dashed areas do not fall within the approved temperature rise range of the unit.
Fig. 25 — Monoport Burners
—25—
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