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TABLE 11—GAS RATE (CU FT/HR)
SECONDS
FOR 1
REVOLUTION
10
11
12
13
14
15
30
31
32
33
34
35
26
27
28
29
20
21
22
23
24
25
16
17
18
19
40
41
42
43
44
45
36
37
38
39
46
47
48
49
100
97
95
92
90
88
86
84
82
80
78
76
75
73
SIZE OF TEST DIAL SECONDS
1 2 5 FOR 1 cu ft
360 cu ft
720 cu ft
1800
REVOLUTION
50
327
300
277
257
240
655
600
555
514
480
1636
1500
1385
1286
1200
51
52
53
54
55
277
267
257
248
240
232
225
218
212
206
450
424
400
379
360
343
327
313
300
288
138
133
129
124
120
116
113
109
106
103
225
212
200
189
180
171
164
157
150
144
1125
1059
1000
947
900
857
818
783
750
720
692
667
643
621
600
581
563
545
529
514
80
82
84
86
88
90
72
74
76
78
60
62
64
66
68
70
56
57
58
59
200
195
189
185
180
176
172
167
164
160
157
153
150
147
500
486
474
462
450
439
429
419
409
400
391
383
375
367
92
94
96
98
100
102
104
106
108
110
112
116
120
124
36
35
35
34
33
33
39
38
38
37
32
31
30
29
45
44
43
42
41
40
50
48
47
46
60
58
56
54
53
51
64
63
62
61
SIZE OF TEST DIAL
1 2 5 cu ft
72 cu ft
144 cu ft
360
71
69
68
67
65
141
138
136
133
131
355
346
340
333
327
100
97
95
92
90
88
86
84
82
80
129
126
124
122
120
116
112
109
106
103
250
243
237
231
225
220
214
209
205
200
321
316
310
305
300
290
281
273
265
257
72
71
69
68
67
65
78
76
75
74
64
62
60
58
196
192
188
184
180
178
173
170
167
164
161
155
150
145
WARNING: Disconnect 115-v electrical power before changing speed tap. Failure to follow this warning could result in personal injury.
TABLE 13—BLOWER OFF DELAY SETUP POSITION
PINS
Time (in sec)
1 AND 2 2 AND 3 3 AND 4 4 AND 5
90 120 150 180
D.
Set Thermostat Heat Anticipator
When using a nonelectronic thermostat, the thermostat heat anticipator must be set to match amp draw of the electrical components in R-W circuit. Accurate amp draw readings can be obtained at thermostat subbase terminals R and W. Fig. 49 illustrates an easy method of obtaining actual amp draw. The amp reading should be taken after blower motor has started and furnace is heating. Connect ammeter wires as shown in Fig. 49. The thermostat anticipator should NOT be in the circuit while measuring current. If thermostat has no subbase, the thermostat must be disconnected from R and W wires during current measurement.
See thermostat manufacturer’s instructions for adjusting heat anticipator and for varying heating cycle length.
For an electronic thermostat, set cycle rate for 3 cycles per hour.
VI.
CHECK SAFETY CONTROLS
This section covers the safety controls that must be checked before the installation is complete. The flame sensor, gas valve, and pressure switch were all checked in the Start-up prodecure section as part of normal operation.
A.
Check Primary Limit Control
This control shuts off combustion control system and energizes air-circulating blower motor if furnace overheats. Recommended method of checking this limit control is to gradually block off return air after furnace has been operating for a period of at least
5 minutes. As soon as limit control has shut off burners, return-air opening should be unblocked to permit normal air circulation. By using this method to check limit control, it can be established that limit is functioning properly and operates if there is a restricted return-air supply or motor failure. If limit control does not function during this test, cause must be determined and corrected.
B.
Check Pressure Switch
This control proves operation of draft inducer. Check switch operation as follows:
1. Turn off 115-v power to furnace.
2. Remove main furnace door and disconnect inducer motor lead wires from wire harness.
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
HOOK-AROUND
VOLT/AMMETER
4. To change blower motor speed selections for heating mode, remove blower motor lead from control center HEAT terminal. (See Fig. 33.) Select desired blower motor speed lead from 1 of the other motor leads and relocate it to HEAT terminal. See Table 12 for lead color identification. Reconnect original lead on SPARE terminal.
Follow this same procedure for proper selection of COOL speed selection.
TABLE 12–SPEED SELECTOR
COLOR
Black
Yellow (When Present)
Blue
Red
White
SPEED
High
Medium High
Medium Low
Low
Common
FACTORY-
SHIPPED
CONNECTION
Cool
Spare
Heat
Fan
Com
R Y W G
10 TURNS
C.
Blower Off Delay (Heat Mode)
The blower off delay has 4 adjustable settings from 90 sec to 180 sec. (See Table 13.) The blower off delay jumpers are located on the furnace control board (See Fig. 33.) To change the blower off delay setting, move the jumper from one set of pins on the control board to the pins used for the desired blower off delay. Factory blower off delay setting is 120 sec.
—41—
FROM UNIT 24-VOLT
TERMINAL BLOCK
EXAMPLE:
5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS
= 0.5 AMPS FOR THERMOSTAT SETTING
A80201
Fig. 49—Amp Draw Check with Ammeter
3. Turn on 115-v power to furnace.
4. Set thermostat to "call for heat" and wait 1 minute. When pressure switch is functioning properly, hot surface igniter should NOT glow, and status code LED flashes a 31 fault.
If hot surface igniter glows when inducer motor is disconnected, shut furnace down immediately. Determine reason pressure switch did not function properly and correct condition.
5. Turn off 115-v power to furnace.
6. Reconnect inducer motor leads, reinstall main furnace door, and turn on 115-v power supply.
CHECKLIST
1. Put away tools and instruments. Clean up debris.
2. Verify manual flame rollout reset switch has continuity.
3. Verify that blower and main access doors are properly installed.
4. Cycle test furnace with room thermostat.
5. Check operation of accessories per manufacturer’s instructions.
6. Review User’s Guide with owner.
7. Leave literature packet near furnace.
—42—
CHECKLIST—INSTALLATION
LOAD CALCULATION
____________ Heating Load (Btuh)
____________ Cooling Load (Btuh)
____________ Furnace Model Selection
VENT PIPING
Termination Location
________
________
________
________
________
________
________
Roof or Sidewall
Vent Pipe Length
Vent Pipe Elbow Quantity
Pipe Diameter Determined from Sizing Table
Pipe Sloped To Furnace
Pipe Insulation
Over Ceilings
Low-Ambient Exposed Pipes
________
________
________
________
________
Condensate Drain
Unit Level or Pitched Forward
Internal Tubing Connections Free of Kinks and Traps
External Drain Connection Leak Tight and
Sloped
Condensate Trap Primed before Start-Up
Heat Tape Installed if Required
________
________
CHECKLIST—START-UP
Gas Input Rate (Set Within 2 percent of
Rating Plate)
Temperature Rise Adjusted
________
________
Thermostat Anticipator
Anticipator Setting Adjusted or
Cycle Rate (3 Cycles per Hr) Selected
Safety Controls Check Operation
________
________
Primary Limit
Pressure Switch
—43—
© 2003 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231 —44— Printed in U.S.A.
345m408 Catalog No. 5334-520
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