Bryant 585B - Manual (Page 10)

TABLE VI-AIR DELIVERY (FtVMin) AT INDICATED TEMPERATURE
RISE AND RATED HEATING INPUT
585B
Size
Heating
Input (Btuh)
Temperature Rise (°F)
35 37.5 40 42.5 45 47.5 50 52.5 55 57.5 60 62.5 65 67.5 70 72.5 75
018050
& 024050
40,000* 804 751 704 662 626 593 563 536 512 490 469 450 433 417 402 388 375
50,000 1032 963 903 850 802 760 722 688 657 628 602 578 556 535 516 498 481
024075, 030075,
& 036075(10)
60,000* 1206 1126 1056 993 938 889 844 804 768 734 704 676 650 626 603 582 563
75,000 1548 1444 1354 1275 1204 1140 1083 1032 985 942 903 867 833 802 774 747 722
036075(30) 60,000* 1206 1126 1056 993 938 889 844 804 768 734 704 676 650 626 603 582 563
75,000 1548 1444 1354 1275 1204 1140 1083 1032 985 942 903 867 833 802 774 747 722
042100 80,000* 1608 1501 1407 1325 1251 1185 1126 1072 1024 979 938 901 866 834 804 777 751
100,000 2063 1926 1806 1699 1605 1520 1444 1376 1313 1256 1204 1156 1111 1070 1032 996 963
036125, 048125,
& 060125
100,000* 2011 1877 1759 1656 1564 1481 1407 1340 1279 1224 1173 1126 1083 1043 1005 971 938
125,000 2579 2407 2257 2124 2006 1901 1806 1720 1641 1570 1505 1444 1389 1337 1290 1245 1204
060150 120,000* 2413 2252 2111 1987 1877 1778 1689 1608 1535 1469 1407 1351 1299 1251 1206 1165 1126
150,000 3095 2889 2708 2549 2407 2281 2167 2063 1970 1884 1806 1733 1667 1605 1548 1494 1444
*Rated heating input as manufactured with factory-installed burner orifices. Higher inputs shown for each size are the maximum rated
inputs using field-installed burner orifices.
NOTE: Shaded portions of the table are beyond the rated temperature rise range.
F. Airflow and Temperature Rise
The heating section is designed for operation within a tem­
perature rise range of 35 to 70°F for units rated up to 75,000
Btuh input (except size 036075, 3-phase units), and within a
range of 45 to 75°F for units with inputs rated at 80,000
Btuh or higher.
Temperature rise is the difference of the air temperature in
the return duct and the air temperature in the discharge
duct at the unit.
Table VT shows the air delivery at various temperature rises
for both A.G.A.-certified input ratings for each size unit.
For heating operation, it is recommended that the airflow
.produces a temperature rise that falls within the range
stamped on the unit rating plate.
Refer to Section VIII, part B, of these instructions to deter­
mine and adjust both the heating and cooling airflow.
G. Sequence of Operation (Heating)
The following sequence of operation pertains to model 585B,
208- or 230-V, 3-phase units; size 036075, 036125, 042100, or
048125; however, the sequence of operation of all other units
is very similar. Refer to the line-to-line wiring diagram in
Figure 13.
NOTE:
Although the actual unit wiring may vary slightly
from that shown in Figure 13, the sequence of operation will
not be affected.
With the room thermostat SYSTEM switch in HEAT posi­
tion and FAN switch in AUTO position, the sequence of
operation is as follows:
Model 585B is equipped with the intermittent RELITE-type
pilot that does not have a standing flame, gas flow to the
pilot gas valve portion of the main gas valve 5F when the
pilot gas cock is open. The unit is now in a “standby” condi­
tion, ready for a “call for heat” from the room thermostat.
When the room thermostat “calls for heat,” control lead R is
connected to control lead W through the room thermostat.
The 821 time-delay blower relay 2G becomes energized
through lead W. After a short delay, during which time the
following burner ignition sequence of operation is com­
pleted, the blower relay contacts 2G close and the circuit to
the blower motor 3D2 is completed. This circuit energizes
the blower motor 3D2, starting the blower.
The circuit between R and W through the room thermostat
simultaneously energizes the pilot gas valve portion of the
main gas valve 5F and the pilot igniter 6F. The energized
pilot gas valve portion of the main gas valve 5F permits gas
flow to the pilot 6H.
NOTE:
The pilot gas valve portion of the main gas valve 5F
is a solenoid consisting of a “pick” and a “hold” coil. Both
coils must be energized to open the valve, but only the
“hold” coil must be energized to keep the pilot gas valve
open.
The energized pilot igniter 6F sends a high-voltage charge
to the pilot electrode 6H, producing a spark that ignites the
pilot flame. The pilot flame sensing monometal switch
proves the presence of the pilot flame. Approximately 40 to
60 seconds after the pilot flame is established, pilot 6H
switches its contacts, energizes the main gas valve 5F,
deenergizes the pilot igniter 6F, and deenergizes the “pick”
coil of the pilot solenoid. The main gas valve 5F is heat mo­
tor operated; therefore, after approximately 10 seconds, the
main gas valve 5F opens permitting gas flow to the burners
where the gas is ignited by the pilot 6H.
When the room thermostat “call for heat” is satisfied, the
circuit between R and W through the room thermostat
breaks and gas flow through the main gas valve 5F is
stopped. The gas flow to pilot is also stopped and the pilot
flame goes out.
The 821 time-delay blower relay 2G is deenergized. There
will be a delay before the heating relay contacts 2G open.
When these contacts do open, the blower motor 3D2 is
deenergized.
The unit has now returned to a “standby” condition, waiting
for the next “call for heat” from the room thermostat.
H. Limit and Pressure Switch Operation
The furnace limit switch 7H (Figure 13) functions to shut off
the gas valve and main burner operation if the furnace leav­
ing air temperature exceeds 175°F.
The pressure switch 7P (Figure 13) is only required when
the unit has been converted for propane gas operation. This
switch is part of the field-installed propane conversion kit.
See the conversion kit Installation Instructions for opera­
tion of the pressure switch.
The normally closed furnace limit switch 7H completes the
control circuit through the W pigtail lead to the gas valve
5F. See Figure 13. Should the leaving air temperature rise to
175°F, the switch opens and the W control circuit is broken.
Any interruption in the control circuit through the W pig­
tail lead to the gas valve instantly closes the gas valve and
stops gas flow to the burners and pilot.
The control circuit through the gas valve to the blower relay
2G is still closed and the blower motor 3D2 will continue to
run.
When the leaving air temperature drops to the limit switch
^ low-temperature setting, the switch closes, completing the
W control circuit. The electric-spark ignition system cycles
and the unit returns to normal heating operation.
VIII. COOLING STARTUP AND ADJUSTMENTS
CAUTION:
Complete the stepsin Section VT before starting
unit.
Do not jumper anj" safety devices when operating unit.
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