Bryant 478-90 User Manual
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ALL WEATHER
HEATING & COOLING UNIT
0 478
ยง Size 90
PDS 478.90.1 10/11/68
__ ..i
SPECIFICATIONS
This equipment is a gas heating and gas cooling all-weather unit designed for roof-top or ground
level installations.
It makes use of an air-cooled Bryant 90-452 gas-fired water chiller combined with a Bryant
300-378 heating unit conveniently mounted on an integral base for easy installation. 'Tie unit is
rated at 90,000 Btuh cooling and 300,000 Btuh heating input. 'The heating can be modulated to
100,000 Btuh input for natural gas by using a modulating gas control kit, Part No. 60119CO2. The
gas-fired chiller is standard with automatic fuel modulation to save gas under low load conditions.
Installation does not interfere with other building trades. No inside floor space and no special
vents are required. Just set the unit on slab or adequate roof support and connect duct, gas supply
and electric supply. 'The Bryant absorption cycle is already charged and ready for operation.
The weatherproof cabinet is made from heavy gauge zinc-coated steel; the chiller finish is baked-
on enamel, and the conditioned-air section is lined with fiberglass to insulate and assure quiet
operation.
Removable panels allow easy access to all components and controls for both heating and cooling.
Automatic pilot reignition eliminates the need for seirvice calls due to pilot outage; a stainless
chromized steel heat exchanger promises long life .
1 . Transformer
2. Blower motor
3 . Combustion air blower motor
4 . Fan relay cooling
5 . Delay relay heating
6 . Combustion air fan relay
10. Gas valve
11. Limit switch adj.
12 . Limit switch non-adj.
13 . Combustion air pressure switch 22
14 . Power relay (cooling) 23
15 . Condenser fan motor 24
7 . Resistor 16. Chilled water pump
8. Pilot gas pressure switch 17. Solution pump
9 . Pilot auto reignition 18. High temp cut-out (cooling)
AIR DELIVERY AT INDICATED EXTERNAL S.P. WITH WET COIL
CFM
2500
3000
3500
4000 835
Shaded portions of the table are beyond the standard drive range or motor horsepower. Standard drive range 540-870 RPM.
0
RPM BMP RPM
500
650
740
.464
.650
.900
1.20
0.1 " 0.2"
BHP RPM BHP RPM BHP
620
700
790 .966 825
890
.500
695
750 .798 800
.734
1.30 920 1.38 960
.560
1.05
0.3"
RPM BHP
725 .665 775
840 .932 870
.866
870
1.10
1.45
900 1.20 940
990
0.4" 0.5" 0.6" 0.7"
RPM BHP
.732
1.55 1025
805 .798
1.00
1.30 980
1.70 1060 1.80
RPM
BHP
860
.865 900 .932
910 1.10
1.33 1005 1.43
RPM BHP
1.20 1000
955
- -
19
20
; 21
RPM
940
1050
0.8"
-
High t
Part 1(
High p
Gas Vc
Auto p
Pilot g
BHP
1.00
1.25
1.50
-
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