Bryant 394 Gas User Manual

Installation Ins!

GAS-FIRED FORCED AIR FURNACE

394

Series G

Size 50 thru 220

INTRODUCTION

Before installing the furnace, refer to Bryant Form

No. 39003D1 “Procedure for Gas Appliances”
(packaged with the equipment) for information con
cerning combustion, venting, 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 heat
ing installation. They are manufactured with two types
of blowers: belt and direct drive. The three smaller

sizes (Series G), 50, 80, and 100. are direct drive only.
All sizes incorporate a low-voltage terminal strip for
convenience of field wiring (except HL and HH
Models).

The optional equipment available includes: Counter
flow Box; Side and Rear Drop Ducts; Side Filter
Racks; Cooling Coil Housing; Combustible Floor
Base Packages, for Counterflow Applications; Cooling
Relay Kit, for field conversion.

CAUTION:

1 ( iiimli-!iImv liii[M,.e mus' bv ui'Killvd kii .m :ip

proved non-combustible base.

2 liL siiic icmpci.iMtii. Use ll■>l■^ no! c\».cci{ ili.i
spcs-ilhil on ihc mil! i.iimu pkiic

' lie suic to chci.l' all ci'iiiiols iiii piiipci opt-i.i'ioi

upon cvimplction of installalivm.

4. Duralast filler on 125 and 137 iipflow fu.maces mus

be used with a skle filter rack or rear drop duct.

Cancels 39394D66

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.

If not already checked when lighting the main burner,

check the proper operation of this valve by moving
the room thermostat pointer above and below room
temperature and observing that the main burners light
on call for heat and go off when the pointer is moved
below the room temperature setting. All Bryant auto
matic gas control valves have a delay when opening
or closing.

Automatic Pilot

To check the pilot operation, follow the instructions
below:

Attach a low-voltage test light to electrical leads of gas
valve. With thermostat set above room temperature,
shut off gas supply to burners and pilot, with main
manual shutoff valve. If test light goes out within 45
seconds, pilot is functioning properly. If light does not

go out within 60 seconds, replace pilot.

39394D73
3/30/72

I. CLEARANCE REQUIREMENTS

The upflow furnace design is certified for use on com
bustible floors.

The Model 394 design is certified by the American Gas
Association, Inc., for installation in a closet or alcove

provided the following clearances are maintained.

Sides............................................................0" (1")*

Back

............................................................

Top of Plenum.............................................3" (0")*

Vent Connector

Front............................................................6" (6")*

* Figures shown in parentheses are approved clearances

when the furnace is installed as a counterflow furnace.

Bryant Automatic Gas Control Valve

Note: On units equipped with an A-643 Bryant auto
matic gas control valve, there are three positions for

...........................................

II. CONTROLS

0" (1")*
6" (6")*

Pilots with Thermocoupie Elements

The D2 100% shutoff propane and D5 100% shutoff
natural gas controls have pilots equipped with thermo
couple elements.

The pilot flame should surround the tip of the thermo
couple. It should also extend downward to include

3/8 to 1/2 inch of the thermocouple tip. The flame
must not come in contact with any other part of the
thermocouple.

D2 Propane

The thermocouple transforms heat energy from the
pilot flame into electrical energy. The current thus
generated is sufficient to operate the 100% inline shut
off valve. The Bryant automatic gas control valve is

powered externally from the transformer, and operates
independently of the inline shut-off valve. When there

UPFLOW
FURNACE

A70652

A.G.A. RATINGS BTU/HR

Natural Propane

Model

No.

50-394

80-394
100-394
125-394
137-394
165-394

190-394 190,000 152,000

220-394 220,000 176,000

Model No.

50-394 16-1/4

80-394
100-394 18-1/4
125-394 20-1/4
137-394 20-1/4
165-394 28-1/4
190-394

220-394
*Optional gas inlet right and left sides provided. T = 33-5/8 and S = 3-1/2 on 50 thru 137 sizes only.

Input

50,000 40,000 50,000 40,000

80,000 64,000 75,000 60,000
100,000 80,000 100,000 80,000
125,000
137,500
165,000

A

26 46 14-5/8

16-1/4

26
26
26
26 46

36-1/4
36-1/4

28-13/16
28-13/16
28-13/16

Bonnet

Capacity

100,000 125,000 100,000
110,000
132,000 150,000 120,000

C D E

B

46 14-5/8
46 16-5/8 19-3/4
46 18-5/8 19-3/4

51
51
51

Input

Not Available

175,000

200,000 160,000

19-3/41
¡9-3/4

18-5/8 19-3/4

26-5/8

17-3/4 2-1/2 5 6" 25-1/4

34-5/8

17-3/4

34-5/8

17-3/4 2-1/2 5 (2) 5"

Bonnet

Capacity

140,000

F G

2-9/16

1/2

2-9/16

1/2

2-3/4 5"

1/2

2-3/4

1/2

2-3/4

1/2

2-1/2 5 (2) 5" 33-1/4

Gas Connection

Sizes

Natural Propane

1/2
1/2
1/2
1/2
1/2
1/2

1/2

1/2

H

4"

12-1/4

4"

12-1/4
14-1/4
18-1/4

5".
5" 18-1/4 22-5/8

33-1/4

BOTTOM OPTIONAL

RETURN SIDE FILTER RACK

OPENING EITHER SIDE

1/2
1/2
1/2
1/2
1/2

(2) 14 X 25 X 1 .

1/2

(1) 16 X 25 X 1
(1) 20 X 25 X 1

1/2

(1) 16 X 25 X 1

1/2

(1) 20 X 25 X 1

K

J

22-5/8
22-5/8
22-5/8
22-5/8 1-1/2

23-5/16
23-5/16
23-5/16

Bottom

Filter
Sizes

14 X 25 X 1
14 X 25 X 1
16 X 25 X 1
20 X 25 X 1
20 X 25 X 1

L

M

1-1/2
1-1/2
1-1/2

1-1/2

2-5/8 23

23

2-5/8

23

2-5/8

Side
Filter
Sizes

14 X 25 X 1
14 X 25 X 1
16 X 25 X 1
20 X 25 X 1
20 X 25 X 1

(2) 16 X 25 X 1

(2) 16 X 25 X 1

(2) 16 X 25 X 1

N P R S*

1-1/4

12
12
14
18
18

23
23
23
23
23

24 2-1/8
24
24

2-1/8

1-1/4

2-1/8

1-1/4

2-1/8

1-1/4

2-1/8

1-1/4 2-1/8

8-5/8
2-1/8 8-5/8
2-1/8 8-5/8

A66384

Approx.

Shipping

Weight

135
153
178
200
202
282

365

365

T*

2-7/8

25-7/16

2-7/8

25-7/16

2-7/8

25-7/16

2-7/8

25-7/16

2-7/8 25-7/16

30-5/8

4-1/16
4-1/16 30-5/8
4-1/16

30-5/8

is a pilot flame, the current generated by the thermo
couple holds the 100% inline shut-off valve in the open
position and the gas control valve controls the flow
of gas. Should the pilot go out, no current will be
generated by the thermocouple and the 100% inline
shut-off valve will close. No gas can then flow to the
pilot.

D5 Natural

Should the pilot go out, no current will be generated
by the thermocouple and the pilot-relay will close,
shutting off the gas to the pilot, and breaking the elec

trical circuit to the Bryant automatic gas control valve.

821/822 Adjustable Fan Control

The Model 394 Furnace incorporates the 821/822
relay for fan control. (The 821 relay is used with the

643 gas valve on furnace sizes 50 through 165 natural

gas; the 822 relay is used with the 641 valve on sizes

190 and 220 and all propane units.) The 821/822 has a
field-adjustable differential. The “max. off” setting on
the dial is for the longest “off” time and shortest

“on” time.

When facing the front of the furnace, the “off” cycle
is lengthened by moving the adjustment lever to the

Figure 1 - Control Section (D5 pilot relay shown)

left. The “off’ cycle is shortened by moving the lever
to the right. The adjustment of the “off’ cycle has the
opposite effect on the “on” cycle; however, to a lesser
degree.

-2-

BASEMENT
FURNACE

Model

No.

50-394

80-394
100-394
125-394
137-394
165-394
190-394

220-394

A.G.A. RATINGS BTU/HR

Natural Propane

Bonnet

Input

Capacitj Input
50,000
80,000

100,000
125,000
137,500
165,000
190,000
220,000

40,000 50,000
64,000

75,000 60,000

80,000 100,000

100,000

125,000 100,000
110,000
132,000

150,000 120,000
152,000

175,000 140,000 36-1/4 43-3/8 51
176,000

200,000 160,000 36-1/4

Bonnet

A

C

В

D

E F

H

G

J*

Capacity Nat.

40,000

80,000

Not available

40-9/16

16-1/4

40-9/16

16-1/4

40-9/16

18-1/4

40-9/16

20-1/4

40-9/16

20-1/4

43-3/8

28-1/4

43-3/8 51 34-5/8

46
46
46
46

46

14-5/8
16-5/8
18-5/8
18-5/8

19-3/4 2-1/2
19-3/4
19-3/4
19-3/4

19-3/4 2-1/2

14-5/8

51 26-5/8 17-3/4

17-3/4

34-5/8

17-3/4

2-1/2
2-1/2
2-1/2
4-1/2
4-1/2
4-1/2

4"

2-9/16

4"

2-9/16

2-3/4 5"

5"

2-3/4

5"

2-3/4
4-1/2

6" 30-5/8 4-1/16
5-1/8 2-5"
5-1/8 2-5"

25-7/16
25-7/16

25-7/16
25-7/16
25-7/16 2-7/8

30-5/8
30-5/8

GAS CON

K*

1/2

2-7/8

1/2

2-7/8

1/2

2-7/8
2-7/8 1/2

1/2
1/2
1/2

4-1/16

1/2

4-1/16

SIZES

Prop.
, 1/2

14 X 25 X 1

1/2 14 X 25 X 1

16 X 25 X 1

1/2
1/2 20 X 25 X 1

20 X 25 X 1

1/2

Two 16 X 25 X 1

1/2
1/2 Two 16 X 25 X 1

Two 16 X 25 X 1

i/i

Filters

Approx.

Shipping

Weight

(Lb.)

Ratings are certified for altitudes to 2,000 feet for all gases. Ratings for altitudes over 2,000 feet are 4% less for each 1,000 feet above sea level.
Return air compartment shipped separately, knocked down.

*Optional gas inlet right and left sides provided. J = 33-5/8 and K= 3-1/2 on 50 thru 137 sizes only.

COUNTERFLOW
FURNACE

166

192
213
238
240
343 .
428
428

A.G.A. Ratings BTU/HR

Model

No.

50-394

80-394
100-394
125-394
137-394
165-394

190-394
220-394

Natural Propane

Bonnet

Capacity

Input

40,000

50,000

80,000 64,000 75,000 60,000 16-1/4 26
100,000 80,000
125,TO 100,000
137,500

110,000

165,000

132,000

19O,0OO

152,000

220,000

176,000

200,000 160,000

Bonnet

Capacity

Input
50,000 40,000 16-1/4 26

100,000 80,000
125,000 100,000 202Щ

Not available
150,000 120,000
175,000 140,000

A В С D Е

18-1/4 26

20-1/4
28-1/4 28-13/168026-1/4
36-1/4 28-13/16 80 34-1/4
36-1/4

26
26 75

28-13/16

—
—

Н—

75

80 34-3/4

*Add 1-1/4" when installed with base on combustible fioor.
tOptional gas inlet right and left sides provided. L = 33-5/8 and K =

14-3/4
14-3/4

16-3/4
18-3/4
18-3/4

G

тщ

2-3/4

ТЩ

гЗТ4

2-3/4
4-1/2
5
5

F

4" 12-5/8 22-5/8
4" 12-5/8

14-5/8

5"
5" 18-518 22-5/8

18-5/8 22-5/8

5"

25-5/8

6"

33-5/8

(2) 5"

33-5/8 23-5/16

(2) 5"

Н J

22-5/8
22-5/8

23-5/16
23-5/16

3-1/2 on 50 thru 137 sizes only.

-3-

Gas Con

Kt*Lt

1-1/2

2-7/8 25-7/16
1-1/2 2-7/8 25-7/16
1-1/2

2-7/8 25-7/16 1/2 1/2

тш

1-7/8 25-7/16
1-1/2

1-7/8 4-1/16
1-7/8 4-1/16 30-5/8 1/2 1/2
1-7/8

25-7/16

2-7/8

30-5/8 1/2

30-5/8 1/2 1/2

4-1/16

Sizes

Nat. Prop.

1/2
1/2 1/2

1/2
1/2

Filters

1/2

16 X 20 X 1 166
16 X 20 X 1 185

Two 10 X 20 X 1 210

1/2

Two 14 X 20 X 1

1/2

Two 14 X 20 X 1

1/2

Two 16 X 20 X 1
Two 20 X 20 X 1
Two 20 X 20 X 1

A66383

Approx.

Shipping

Weight

(Lb.)

235
237

325
405
405

I

Figure 2 - Control Box, Cover Removed,

No Internal Wiring Changes

TO HEATING AND
COOLING CONNECTIONS
OF THERMOSTAT
P/N 34427D030
a 34427D031

\ TO CONDENSER

> CONTACTOR COIL

I CONNECTIONS

A68367

VOF THERMOSTAT
^P/n 34427D030

a 34427D031

] TO CONDENSER

I LOW VOLTAGE
(^LEAD OR

j TERMINAL STRIP

NOTE-'

WIRE WITH* IN FIGURE 2 IS

A68368 CONDENSEFTHAS TRANSFORMER.

Figures 3 - Control Box, Cover Removed,

Showing Internal Wiring Changes

REMOVED, AND DISCARDED WHEN

TO HEATING AND
COOLING CONNECTIONS

Low-Voltage Wiring

Field low-voltage connections are made at the low­l^oltage terminal strip. See Figure 6 for heating only.
For Model 394 Furnaces used in conjunction with

slectric or gas air conditioning units that do not have
4n integral transformer, see Figure 2. If the 394 Fur­fiace is used in conjunction with an electric or gas air
jonditioning unit having an integral transformer, see
Figure 3.

Figure 3 shows a field-installed wire running from one
side of the air conditioning transformer, through the

4ole marked “F” in the terminal strip to the blower

relay in the control box for the Model 394 Furnace.

The wire marked * in Figure 2 is removed from the

:ontrol box and discarded.

Limit Control

This control shuts oflF the gas and energizes the blower
notor if the furnace becomes overheated.

The recommended method of checking the limit control

s to gradually block off the return air after the furnace

,ias been operating for a period of at least five minutes.
\s soon as the limit has proven safe, the return air
opening would be unblocked to permit normal air
jirculation. By using this method to check the limit

control, it can be established that the limit is function-

ng properly and will “fail-safe” if there is a motor
ailure.

Thermostat Location

The room thermostat should be located where it will
re in the natural circulating path of room air. Avoid

locations where the thermostat would be exposed to
cold air infiltration, drafts from windows, doors, or
other openings leading to the outside, or exposure to
air currents from warm or cold air registers; or to ex
posure where the natural circulation of the air is cut
off—such as behind doors, above or below mantels,
shelves, etc.

The thermostat should not be exposed to heat from
nearby radiators, fireplaces, radios, televisions, lamps,
or rays from the sun. Nor should the thermostat be
mounted on a wall containing pipes or warm air ducts,

or a flue or vent which could affect its operation and
prevent it from properly controlling the room tempera
ture. Any hole in the plaster or panel through which
the wires pass from the thermostat should be adequately
sealed with suitable material to prevent drafts from
affecting the thermostat.

The heat anticipator on the thermostat should be set
at 0.8 amps.

III. ELECTRICAL CONNECTIONS

Line-Voltage Wiring

All electrical connections are to be made in accordance
with the local electrical codes. A permanent, live,
separately fused electric power supply, complete with

manual switch, should be provided for the furnace.

Field wiring connections should be made in accordance

with the unit wiring diagrams.

-4-

Adjustment of Blower Speed

^ our-Speed Direct Drive

To change motor speed taps, remove the motor tap
lead (see Figure 1) and relocate it on the desired ter
minal on the plug-in terminal block/speed selector
located on the dividing panel. See Table I.

Belt Drive

The blower speed may be changed by opening or clos
ing the motor pulley. When adjusting blower speed,
be certain that the pulleys are properly aligned.

TABLE 1 - Factory Setting Blower Motor Chart

Drive Type

Unit
Size

50
80

100 2

125

137
165 2
190
220

*Use when factory Relay Kit is field installed.

L

Red Blue

to

to*

4
3

1

3

1

2 1

Color Code for Speed Taps

M

Red Blue Red

to

4
3
3 1

3
2

to

to

1
1

1
1

E

4
4
3
2

B

Blue

Red Red Red

to

to

1
1
1

1 1

1

1

1

1
1 1

c

to to

1 1
1

1 1

cx

1

1

Common (white).................................................#C Tap

Hi Speed (black)

..................................................

#1 Tap

Med Speed (blue).................................................#2 Tap

Med-Lo Speed (yellow)....................................# 3 Tap

Lo Speed (red)......................................................#4 Tap

C.AUTION: When adjusting the blower .speed. ma|
certain that the temperature rise acn>ss the heat
changer doe.s not exceed that specified on the rati|

DRIVE TYPES

B — Belt drive heating —minimum cooling
C — Belt drive heating and cooling
X— Belt drive heating—maximum cooling

L — Multi-speed direct drive heating —minimum cooling

E — Multi-speed direct drive heating —maximum cooling with evaporator

blower motor relay.

M —Mutli-speed direct drive heating —minimum cooling with evaporator

blower motor relay.

IV. CARE AND MAINTENANCE

Cleaning

The heat exchanger should be examined periodically
to see if there has been an accumulation of rust, soot,
etc. Clean as follows;

1. Disconnect pilot tubing.

2. Disconnect electrical lead from pilot. (In case of
100% shut-off controls, disconnect pilot thermocouple

lead from pilot relay or inline shut-off valve.)

3. Remove front plate from draft diverter (4 sheet-

metal screws).

4. Remove burners and pilot as follows:

a. Remove Tinnerman clamp from burner-holding

stud.

b. Slide burner off orifice and remove under

manifold.

c. Pilot is attached to one burner and is removed

with that burner. It is not necessary to detach
pilot before removing burner.

5. Remove metal angle strip holding flue baffles in
place. See Figure 4.

6. Remove flue baffles. See Figure 5.

7. Use flexible-handled steel cleaning brush to loosen
scale and soot. Remove scrapings from bottom of
combustion chamber.

8. Reassemble furnace by reversing above procedure.

NOTE: There is a slot in the back of the heat ex
changer for the back tip of the burner to fit into. When

properly placed, the burner will fit into this slot and

will be level.

Care of Blowers

All motors on the belt drive blowers are provided with
oil cups and should be oiled at least twice a year with
a nondetergent SAE 30 oil.

Belt Tension

Adjust tension on a V-belt so that the belt deflects
approximately 3/4 to 1 inch when the pressure from
one finger is applied midway between the blower and
motor pulleys. Adjust the tension by turning the motor
adjusting screw.

Filters

Some units are equipped with a permanent fiber filter

(recognizable by its distinct green color). To clean this
filter, run water through the fibers from the leaving
air side. Do not spray this filter with water-soluble oil.

Figure 4 - Flue-Baffle Retainer Strip

A66475

Figure 5 - Removing Baffles

-5-

A66476

LINE-TO-LINE WIRING DIAGRAMS

THERMOSTAT CONNECTIONS-HEATING ONLY

note: remove \nter-

NAL JUMPER SETWIEM

1 W ^ J TERMtHALS.

I- —11

Figure 6 - Units without Heat-Cool Relay (HL Drive)

Figure 7 - Units with Heat-Cool Relay (M & E Drives)

Figure 8 - Units without Cooling Relay (B Drive)

Figure 9 - Units with Cooling Relay (C & X Drives)

1 A—Transformer

2A—Cooling Relay-SPST
2C—Heat-Cool Relay-SPDT
2G —Heating Relay-SPST

(Heat Motor Operated)

3A —Blower Motor

5A—Automatic Gas Valve
6A—Pilot Switch

(None on Propane)

7H —Limit Control-SPST

(On Counterflow Only)

7K —Limit Control-SPDT

3D —Blower Motor

Factory Line Voltage
Factory Low Voltage
Field Line Voltage

THERMOSTAT 34427D35 (NO ­TERM\WAL CODE). ALSO MODELS

883-P/N 344270030 OR 884­P/N 34427003» THERMOSTAT 4
SUS BASE.

OM-OFF FAN, MODEL 885

P/K| 34427033 TtiEFMOSTAT

t SUB-BASE OR THERMOSTOT

MODEL SBS P/n 344i76<l6 Wrro SUB
BASE P/M 34427034.

A68372

SEQUENCE OF OPERATING-HEATING

When the thermostat calls for heat, the control circuit
is closed between terminals (4 and W). Power from trans
former (lA) energizes automatic gas valve coU (5A) and
heating relay coil (2G) simultaneously. After a short time
delay, automatic gas valve (5A) opens, permitting gas to
flow to the burners where it is ignited by the gas pilot. After
another delay, the heating relay switches its contacts (2G),
starting blower motor (3A or 3D) on its heating speed.

When the thermostat is satisfied, the circuit between
terminals (4 and W) is broken, de-energizing automatic
gas valve coil (5A) and heating relay coil (2G). After a
few seconds, automatic gas valve (5A) closes, stopping
the flow of gas to the main burners. After a longer delay,
heating relay (2G) opens its contacts to stop blower motor
(3A or 3D).

If the furnace overheats for any reason, limit control (7K)
will switch, breaking the circuit to automatic gas valve coil
(5A) and making a circuit to heating relay coil (2G). After

a short delay, the gas valve closes, shutting off the flow of
gas through the main burners. After an additional period of
time, heating relay (2G) closes its contacts, energizing
blower motor (3A or 3D) (if it is not already operating)
on heating speed. It continues to cycle until the fault is
corrected.

On counterflow furnaces, additional limit control (7H)
protects against overheating also. Should this control sense
a high temperature, it opens its contacts, de-energizing
automatic gas valve coil (5A) which, in turn, shuts off the
flow of gas to the main burners. After limit control (7H)
has cooled, its contacts close, automatically energizing
automatic gas valve coil (5A). After a short delay, the valve
opens, permitting gas to flow to the burners where it is
ignited by the pilot. Furnace blower motor (3A or 3D) may
or may not be operating, since it is independent of additional
limit control (7H).

SEQUENCE OF OPERATION-COOLING

When the thermostat calls for cooling, power from trans
former (lA) energizes cooling relay coil (2C), closing its

contacts, and energizing blower motor (3A or 3D) on its
cooling speed. It continues to operate until the thermostat
is satisfied.

When the thermostat is satisfied, the circuit to terminal (G)
is broken, de-energizing cooling relay coil (2C) which, in
turn, opens its contacts, stopping blower motor (3 A or 3D).

-6-