Operating instructions
EXAMPLE: (0-2000 ft altitude)
Furuace input from rating plate is 100,000 Btuh.
Btu heating input Btuicu ft X cu ft.hr
Heating value of gas 975 Bmicu ft
Time for 1 revolution of 2-cu ft dial 70 sec
Gas rate 103 cu ft&r (fi'om Table 12)
Btu heating input 103 X 975 100,425 Btuh.
In this example, the orifice size and manifold
pressure adjustment is within ±2 percent of the
furuace input rate.
SET TEMPERATURE RISE
V.,l[_
Temperature rise must be within limits specified on furnace
rating plate. Recommended operation is at midpoint of rise
range or slightly above. Failure to follow this caution may
result in primary and secondary heat exchanger failure.
Determine and adjust air temperature rise as follows:
i. Place thermometers in return and supply ducts as close to
furuace 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.
2. When thermometer readings stabilize, subtract returu-air tem-
perature from supply-air temperature to determine air tem-
perature rise.
3. Adjust temperature rise by adjusting blower speed. Increase
blower speed to reduce temperature rise. Decrease blower
speed to increase temperature rise.
¥:_ "EY!3;_II_r3
Disconnect 115-v electrical power before changing speed tap.
Failure to follow this warning could result in personal il_jury.
4. To change blower motor speed selections for heating mode,
remove blower motor lead from control HEAT terminal. (See
Fig. 31.) Select desired blower motor speed lead from 1 of the
other motor leads and relocate it to HEAT terminal. See Table
13 for lead color identification. Reconnect original lead on
SPARE terminal.
Follow this same procedure for proper selection of COOL
speed selection.
ADJUST BLOWER OFF DELAY (HEAT MODE)
The blower offdelay has 4 adjustable settings fi'om 90 sec to 180
sec. (See Table 14.) The blower off delay jumpers are located on
the furuace control (See Fig. 31). To change the blower off delay
setting, move the jumper from one set of pins on the control to the
pins used for the desired blower off delay. Factory blower off
delay setting is 120 sec.
Table 14_Blower Off Delay Jumper Positions
Time (in sec) 90 120 150 180
SET THERMOSTAT HEAT ANTICIPATOR
When using a nonelectronic thermostat, the themmstat heat
anticipator must be set to match the amp &aw of the electrical
components in R-W circuit. Accurate amp draw readings can be
obtained at thermostat subbase terminals R and W. Fig. 60
illustrates the easy method of obtaining actual amp &aw. The amp
47
Table 12--Gas Rate (cu ft/hr)
SECONDS SIZE OF TEST DIAL SECONDS SIZE OF TEST DIAL
FOR 1 1 2 5 FOR 1 1 2 5
REVOLUTION Cu Ft Cu Ft Cu Ft REVOLUTION Cu Ft Cu Ft Cu Ft
10 360 720 1800 50 72 144 360
11 327 655 1636 51 71 141 355
12 300 600 1500 52 69 138 346
13 277 555 1385 53 68 136 340
14 257 514 1286 54 67 133 333
15 240 480 1200 55 65 131 327
16 225 450 1125 56 64 129 321
17 212 424 1059 57 63 126 316
18 200 400 1000 58 62 124 310
19 188 379 947 59 61 122 305
20 180 360 900 60 60 120 300
21 171 343 857 62 58 116 290
22 164 327 818 64 56 112 281
23 157 313 783 66 54 109 273
24 150 300 750 68 53 106 265
25 144 288 720 70 51 103 257
26 138 277 692 72 50 100 250
27 133 267 667 74 48 97 243
28 129 257 643 76 47 95 237
29 124 248 621 78 46 82 231
30 120 240 600 80 45 90 225
31 116 232 581 82 44 88 220
32 113 225 563 84 43 86 214
33 109 218 545 86 42 84 209
34 106 212 529 88 41 82 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 185 486 94 38 76 192
38 95 189 474 96 38 75 188
39 92 185 462 98 37 74 184
40 90 180 450 100 36 72 180
41 88 176 439 102 35 71 178
42 86 172 429 104 35 69 173
43 84 167 419 106 34 68 170
44 82 164 409 108 33 67 167
45 80 160 400 110 33 65 164
46 78 157 391 112 32 64 161
47 76 153 383 116 31 62 155
48 75 150 375 120 30 60 150
49 73 147 367 124 28 58 145
Table 13_Speed
COLOR SPEED
Black High
Yellow (When Present) Medium High
Blue Medium Low
Red Low
White Common
Selector
FACTORY-
SHIPPED
CONNECTION
Cool
Spare
Heat
Fan
COM
reading should be taken after blower motor has started and fumace
is heating. Connect ammeter wires as shown in Fig. 60. The
thermostat anticipator should NOT be in the curcuit while mea-
suring 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.