Measure Manifold Pressure (Propane Units) Ð The main burner ori®ces on a propane gas unit are sized for the unit rated input when the manifold pressure reading matches the level speci®ed 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 speci®ed 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.

CHECK BURNER FLAME Ð With burner access panel re- moved, observe the unit heating operation. Watch the burner ¯ames to see if they are light blue and soft in appearance, and that the ¯ames are approximately the same for each burner. Propane will have blue ¯ame with yellow tips. See Fig. 25. Refer to Maintenance section for information on burner removal.

Fig. 25 Ð Monoport Burners

AIRFLOW AND TEMPERATURE RISE Ð The heating sec- tion for each size unit is designed and approved 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 air¯ow must produce a tem- perature rise that falls within the approved range.

Refer to Evaporator Air¯ow and Air¯ow Adjustments sec- tion on page 35 to adjust heating air¯ow when required.

Table 6 Ð Air Delivery (Cfm) at Indicated Temperature Rise and Rated Heating Input

HEATING

 

 

 

 

 

 

TEMPERATURE RISE °F

 

 

 

 

 

 

 

 

INPUT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Btuh)

20

25

30

35

40

45

50

55

60

65

70

 

75

 

80

85

90

40,000

1389

1111

926

794

694

617

556

Ð

Ð

Ð

Ð

Ð

Ð

 

Ð

Ð

 

56,000

2083

1667

1389

1190

1042

926

833

758

Ð

Ð

Ð

Ð

Ð

Ð

Ð

 

80,000

2778

2222

1852

1587

1389

1235

1111

1010

926

855

794

 

Ð

 

Ð

Ð

Ð

95,000

3472

2778

2315

1984

1736

1543

1389

1263

1157

1068

992

 

926

 

868

Ð

Ð

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.

25

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Image 25
Carrier 48SX024-060, 48SS018-060 user manual Monoport Burners, Heating Temperature Rise F Input