Bryant 394B - Manual

Bryant
Airconditioning
Company
installation instructions
GAS-FIRED FORCED-
AIR FURNACE
3 9 4 B & D
Series A
Sizes 050
thru 200
Cancels: 39394D82 39394DP85
11/1/74
INTRODUCTION
Before installing the furnace, refer to “Procedure for
Gas Furnace Installation” (packaged with the equip­
ment) for information concerning combustion, vent­
ing, piping, and other standard installation practices.
Further reference is made to the current edition of the
American National Standard “Installation of Gas
Appliances and Gas Piping,” Z21.30.
Model 394 Gas Furnaces are shipped from the factory
completely assembled and wired ready for indoor
heating installation. They are manufactured with two
types of blowers: belt and direct drive. The four
smaller sizes, 50, 80, 100, and 125, are direct drive
only. All sizes incorporate a low-voltage terminal
strip for convenience of field wiring (except 50,000-
Btuh unit with complete shut-off gas controls.)
This publication covers installation, startup and
maintenance. For accessory installation details, refer
to applicable installation literature.
CAL’TTON: Do Tiot insrall hirnace in a coitosívp or
coiiTaminated almosphcre. Makp sure tliaV all local
ordinance's for coinbusTioii and circiilaTing air supply
are obser\ed.
The design of the 394B&D Upflow Gas-Fired Fur­
naces is A.G.A. certified for installation on com­
bustible flooring in alcoves, basements, closets, or
utility rooms.
CLEARANCE REQUIREMENTS
(in inches)
Sides............................................................................ 1
Back.............................................................................0
Top of Plenum.............................................................1
Vent Connector (single wall)...................................... 6
Type B (double wall)............................................... 1
Front........................................................................ ..6
Provide service clearance of 30 in. at front of unit.
Bryant Automatic Gas Controi Vaive
NOTE: On units equipped with an A-643 Bryant
automatic gas control valve, there are three positions
for the manual valve knob (OFF-PILOT-ON). There
is a position stop at the PILOT position. To move the
manual valve knob from the PILOT position to either
ON or OFF position, the manual valve knob must be
depressed.
A72548
Figure 1—Modei 394D
If not already checked when lighting the main burn­
er, check the proper operation of this valve by
moving the room thermostat pointer above and below
room temperature and observing that the main burn­
ers light on call for heat and go off when the pointer
is moved below the room temperature setting. All
Bryant automatic gas control valves have a delay
when opening or closing.
Fan/Limit Control Operation
At the moment the thermostat calls for heat, the time
delay mechanism of the control is energized. If, due to
pilot outage, the control bimetal element does not
sense a temperature change, the control will turn on
the blower strictly by means of the time delay feature.
If for any reason the time delay is not energized as the
thermostat calls for heat, the control bimetal element
will bring on the blower when it senses a temperature
rise of 50 degrees Fahrenheit (standard differential)
above the turn-off setting. During the blow-down
period and after the thermostat is satisfied, the con­
trol will turn the blower off at the indicated setting
sensed by the control bimetal element.