Check Safety Controls - Bryant 311AAV Series 100 Installation, Start-Up, And Operating Instructions Manual

d. Check and verify orifice size in furnace. NEVER AS-
SUME THE ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.
e. Turn off all other gas appliances and pilots.
f. Jumper R to W/W1.
g. Let furnace run for 3 minutes in low-heat operation.
h. Measure time (in sec) for gas meter to complete 1
revolution. Note reading.
i. Refer to Table 9 for cu ft of gas per hr.
j. Multiply gas rate cu ft/hr by heating value (Btu/cu ft).
NOTE: Measured gas input must be within ± 2 percent of that
stated on furnace rating plate when installed at sea level or derated
at higher altitudes.
k. Remove jumper across R and W thermostat connections
to terminate call for heat.
EXAMPLE: (4300 ft altitude)
Furnace input from rating plate is 88,000 Btuh.
Btu heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 850 Btu/cu ft
Time for 1 revolution of 2-cu ft dial = 85 sec
Gas rate = 85 cu ft/hr (from Table 9)
Btu heating input = 85 X 850 = 72,250 Btuh. In this
example, the orifice size and manifold pressure adjustment
is within ±2 percent of the furnace input rate.
7. Set temperature rise
The furnace must operate within the temperature rise range
specified on the furnace rating plate. Determine the air
temperature as follows:
a. Place thermometers in return and supply ducts as close to
furnace as possible. Be sure thermometers do not see
heat exchangers so that radiant heat does not affect
readings. This practice is particularly important with
straight-run ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine
air temperature rise.
c. Adjust temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. De-
crease blower speed to increase temperature rise.
WARNING: Disconnect 115-v electrical power before
changing speed tap. Failure to follow this warning could
result in personal injury.
d. To change blower motor speed selections for heating
mode, remove blower motor lead from control HEAT
terminal. (See Fig. 22.) Select desired blower motor
speed lead from 1 of the other terminals and relocate it
to HEAT terminal. See Table 10 for lead color identifi-
cation. Reconnect original lead on SPARE terminal.
8. Follow procedure in 5d for selection of COOL and FAN
speeds.
CAUTION: Recheck temperature rise. It must be within
limits specified on the rating plate. Recommended opera-
tion is at the midpoint of rise or above.
9. Set thermostat heat anticipator
TABLE 9—GAS RATE (CU FT/HR)
SECONDS SIZE OF TEST DIAL
FOR 1 1
REVOLUTION Cu Ft
10 360
11 327
12 300
13 277
14 257
15 240
16 225
17 212
18 200
19 189
180
20
21 171
22 164
23 157
24 150
25 144
26 138
27 133
28 129
29 124
30 120
31 116
32 113
33 109
34 106
35 103
36 100
37 97
38 95
39 92
40 90
41 88
42 86
43 84
44 82
45 80
46 78
47 76
48 75
49 73
TABLE 10–SPEED SELECTION
COLOR
White
Black
Yellow
Orange†
Blue
Red
* Continuous-blower speed-as shipped default
† Available on 5–speed blowers only.
a. When using a nonelectric thermostat, the thermostat
heat-anticipation must be set to match the amp draw of
the electrical components in the R-W circuit. Accurate
amp draw readings can be obtained at the wires normally
connected to thermostat subbase terminals, R and W.
Fig. 34 illustrates an easy method of obtaining actual
amp draw. The amp reading should be taken after blower
motor has started and furnace is operating. Connect
ammeter wires as shown in Fig. 34. The thermostat
anticipator should NOT be in th 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 instruc-
tions for adjusting heat-anticipator.
b. When using an elctronic thermostat, set cycle rate for 3
cycles per hr.
V. CHECK SAFETY CONTROLS
The flame sensor, gas valve, and pressure switch were all checked
in the start-up procedure section as part of normal operation.
1. Check Primary Limit Control
—25—
SECONDS SIZE OF TEST DIAL
2 5 FOR 1 1
Cu Ft Cu Ft REVOLUTION Cu Ft
720 1800 50 72
655 1636 51 71
600 1500 52 69
555 1385 53 68
514 1286 54 67
480 1200 55 65
450 1125 56 64
424 1059 57 63
400 1000 58 62
379 947 59 61
360 900 60 60
343 857 62 58
327 818 64 56
313 783 66 54
300 750 68 53
288 720 70 51
277 692 72 50
267 667 74 48
257 643 76 47
248 621 78 46
240 600 80 45
232 581 82 44
225 563 84 43
218 545 86 42
212 529 88 41
206 514 90 40
200 500 92 39
195 486 94 38
189 474 96 38
185 462 98 37
180 450 100 36
176 439 102 35
172 429 104 35
167 419 106 34
164 409 108 33
160 400 110 33
157 391 112 32
153 383 116 31
150 375 120 30
147 367
SPEED AS SHIPPED
Common BLW
High COOL
Med-High SPARE
Med SPARE
Med-Low HEAT
Low* FAN
2 5
Cu Ft Cu Ft
144 360
141 355
138 346
136 340
133 333
131 327
129 321
126 316
124 310
122 305
120 300
116 290
112 281
109 273
106 265
103 257
100 250
97 243
95 237
92 231
90 225
88 220
86 214
84 209
82 205
80 200
78 196
76 192
75 188
74 184
72 180
71 178
69 173
68 170
67 167
65 164
64 161
62 155
60 150