LG 395CAV User Manual

Page 13

(3.) When correct input is obtained, replace regulator

seal cap. Main burner flame should be clear blue,
almost transparent. (See Fig. 13.)

d. High altitude—In the United States gas input on rating

plate is for altitudes up to 2000 ft. Ratings for altitudes
over 2000 ft must be 4 percent less for each 1000 ft
above sea level. To obtain the adjusted altitude rating,
adjust the manifold pressure (see item c) and replace the
main burner orifices as needed. Refer to National Fuel
Gas Code Appendix F, Table F-4 for proper orifice
sizing at high altitudes.

e. Canadian installations only—The Canadian ratings are

approved for altitudes up to 2000 ft for natural and
propane gases. High-altitude ratings are from 2000 ft to
4500 ft above sea level. See Table 8 for nominal burner
orifice size. High-altitude rating includes a 10 percent
derate as required by Canadian standards.

2. Set temperature rise.

Furnace must operate within range of temperature rise
specified on the unit rating plate. Determine the air tem-
perature rise as follows.

a. Place duct thermometers in return and supply ducts as

near furnace as possible. Be sure thermometers do not
"see" heat exchangers so that radiant heat will not affect
thermometer readings. This is particularly important
with straight-run ducts.

b. When thermometer readings stabilize, subtract return-air

temperature from supply-air temperature to determine
temperature rise.

c. Adjust air temperature rise by adjusting blower speed.

Increase blower speed to reduce temperature rise. De-
crease blower speed to increase temperature rise.

WARNING:

Disconnect the electrical power before

changing the speed tap. A failure to follow this warning
can cause personal injury.

d. To change blower motor speed selections for heating

mode, remove blower motor lead from control board
HEAT terminal. (See Fig. 11.) Select desired blower
motor speed lead from 1 of the other terminals and
relocate it to HEAT terminal. See Table 9 for lead color
identification. Reconnect original lead on SPARE termi-
nal.

CAUTION:

Recheck temperature rise. It must be within

limits specified on unit rating plate. Recommended op-
eration is at midpoint of rise or above.

TABLE 7—GAS RATE CU FT/HR

SECONDS

FOR 1

REVOLUTION

SIZE OF

TEST DIAL

SECONDS

FOR 1

REVOLUTION

SIZE OF

TEST DIAL

cu ft

10
11
12
13
14

360
327
300
277
257

720
655
600
555
514

1800
1636
1500
1385
1286

50
51
52
53
54

72
71
69
68
67

144
141
138
136
133

360
355
346
340
333

15
16
17
18
19

240
225
212
200
189

480
450
424
400
379

1200
1125
1059

100
947

55
56
57
58
59

65
64
63
62
61

131
129
126
124
122

327
321
316
310
305

20
21
22
23
24

180
171
164
157
150

360
343
327
313
300

900
857
818
783
750

60
62
64
66
68

60
58
56
54
53

120
116
112
109
106

300
290
281
273
265

25
26
27
28
29

144
138
133
129
124

288
277
267
257
248

720
692
667
643
621

70
72
74
76
78

51
50
48
47
46

103
100

97
95
92

257
250
243
237
231

30
31
32
33
34

120
116
113
109
106

240
232
225
218
212

600
581
563
545
529

80
82
84
86
88

45
44
43
42
41

90
88
86
84
82

225
220
214
209
205

35
36
37
38
39

103
100

97
95
92

206
200
195
189
185

514
500
486
474
462

90
92
94
96
98

40
39
38
38
37

80
78
76
75
74

200
196
192
188
184

40
41
42
43
44

90
88
86
84
82

180
176
172
167
164

450
439
429
419
409

100
102
104
106
108

36
35
35
34
33

72
71
69
68
67

180
178
173
170
167

45
46
47
48
49

80
78
76
75
73

160
157
153
150
147

400
391
383
375
367

110
112
116
120

33
32
31
30

65
64
62
60

164
161
155
150

Fig. 12—Redundant Automatic Gas Control Valve

A95618

MANIFOLD
PRESSURE TAP

GAS
PRESSURE
REGULATOR
ADJUSTMENT

INLET
PRESSURE TAP

ON AND
OFF SWITCH

Fig. 13—Burner Flame

A89020

BURNER FLAME

BURNER

MANIFOLD

TABLE 8—CANADIAN ORIFICE SIZE

GAS

SEA LEVEL

0—2000 FT

HIGH ALTITUDE

2000—4500 FT

Natural

Propane

—13—

→