Bryant 376B User Manual

i nstallation, operatron,
and maintenance instructions

HIGH-EFFICIENCY

DOWNFLOW/HORIZONTAL
INDUCED-COMBUSTION FURNACE

376B

Series A

Sizes 040

thrullS

NOTE: Remove the Energy Guide tag from the furpace

when the installation is complete.

NOTE; This is a highly specialized piece of equipment.

Before beginning the installation, READ THESE

INSTRUCTIONS CAREFULLY AND COMPLETELY.

INTRODUCTION

Before installing the furnace, refer to “Procedure for
Induced-Combustion Gas-Fired Furnaces” (packaged with

the equipment) for information concerning combustion,
venting, piping, and other standard installation practices.
Further reference is made to the current edition of the
National Fuel Gas Code NFPA No. 54-1984/ANSI Z223.1-

1984.
The induced-combustion vent system of this furnace is

designed to operate at zero or negative pressure at the vent
connector outlet. This furnace, therefore, complies with the
National Fuel Gas Code (NFPA No. 54-1984/ANSI Z223.1-

1984), Part 7.14.3.b. This furnace is also hsted by A.G.A. for
use with the type B1 gas vent, as described in the National

Fuel Gas Code, Part 7.3.2.
Each furnace is shipped from the factory completely assem

bled with multispeed direct-drive blower and wired ready for
indoor heating installation. All sizes feature a blower con
trol center with easy-to-read low-voltage terminal strip to
ensure proper connections.

The output capacity and any representations of efficiency
for this product are based on standard Department of
Energy test procedures. The insteJled operation may vary,
depending on installation, weather, or other factors.

Cancels; 39376DP5-A

40376DP5-B

9/1/85

TABLE I—CLEARANCES (In Inches)

Sizes
DOWNFLOW (In Alcove or Closet)

Sides—Single-Wall Vent

Type-B1 Double-Wail Vent 0

Back 0
Top
Front*—Single-Wall Vent 6

Type-B1 Double-Wall Vent

Vent—Single-Wail

Type-BI Double Wall 1

HORIZONTAL (In Alcove)

SidesT 0
Back
Top—Single-Wall Vent

Type-B1 Double-Wall Vent 0
Front*
Vent—Single-Wall

Type-BI Double-Wail 1 1

HORIZONTAL (In Closet)

Sides! 1 1 .
Back 3 3

Top—Single-Wall Vent 2

Type-BI Double-Wall Vent 2 2

Front*—Single-Wall Vent 6 6

Type-BI Double-Wall Vent

Vent—Single-Wall 6 6

Type-BI Double-Wall 1 1

♦Provide a 30-in. service clearance in front of the furnace,
t Indicates supply or return sides when furnace is in the horizontal

position.

040 and 055

3 “ 3
6 6

0 0

18 18

6 6

3 3

075 thrullS

A83215

Figure 2—Horizontal

0
0
0
1
6

1
0

2

The design of the downflow/horizontal gas-fired furnace is
A.G.A. certified for natural and LP(propane) gas and for
installation on combustible fiooring (with optional fioor

base), in alcoves, attics, crawl spaces, basements, closets, or
utility rooms. The design of this furnace line is not A.G.A.
certified for installation in mobile homes, recreation vehi
cles, or outdoors.

BDP Company

TABLE III—RATINGS AND PERFORMANCE*

SIZE Input

Buth*

024040
024055 67,000
036055
036075 90,000
048075 90,000
048095 114,000 95,000 55—85
060095 114,000
060115 137,000

*The-above gas inputs are certified for altitudes to 2000 ft. For elevations above 2000 ft,
tDetermined by U.S. Government tests.
tTentative rating.

48,000 39,000 50—80 0.10 610
67,000 56,000 35—65

Capacity

Buthtt

56,000
75,000 45—75 0.15

75,000
95,000

115,000 45—75 0.20

Temperature

Rise

Range

40—70

40—70
55—85

External Static

Installation comprises the following:

*1. Inspection

*11. Location, Ventilation, and Air for Combustion

*III. Gas Piping

*IV. Venting

V. Supply-Air Plenum Installation (Downflow)

VI. Attic Installation

VII. Crawl Space Installation

VIII. Filter Arrangement

IX. Sequence of Operation

Heating Cooling

Ft=/Min External Static

Pressure

0.12

0.12

0.15 1240

0.20

0.20

*To perform these sections (or installation steps), refer to
the appropriate sections of “Procedures for Induced-Com
bustion Gas-Fired Furnaces” booklet packaged with this
unit.

For accessory installation details, refer to applicable instal
lation literature.

V. SUPPLY-AIR PLENUM INSTALLATION (DOWNFLOW)
A. installation on a concrete slab

1. See Figure 3 for dimensions and location of supply-air

2. Construct hole in floor per dimensions in Figure 4 and

X. Electrical Connections

XI. Startup and Adjustment

XII. Care and Maintenance

3. Place plenum and furnace as shown in Figure 5.

B. Installation on a combustible floor

1. Read Installation Instructions packaged with combus

TABLE II—DIMENSIONS (In Inches)

Size
024040
024055
036055 14-3/1 6
036075 17-1/2
048075 17-1/2 1 5-7/8
048095 17-1/2 1 5-7/8
060095 21 19-3/8
060115 24-1/2 22-13/16

835t

1080

960t

1248
1350
1037 0.5 2010 1/2 P$C 208

reduce.input 4% for each 1000 ft above sea level.

A D

1 4-3/1 6

14-3/1 6 12-9/16

FCTMin

Pressure

0.5 Ш

0.5

0.5

0.5

0.5

0.5 ■ 1590

0.5 1929

12-9/16
12-9/16

1 5-7/8

890t

1157

1230t

1553

E Vent Conn
12-11/16 4
12-11/16
12-11/16

16
16
16

19-1/2

23

Motor

HP & Type

1/5 Páó
1/5 PSC 140
1/3 PSC 142
1/3 PSC 160
1/2 PSC 163
1/2 PSC
1/2 PSC 188

Shipping

Weight

<Lbs)

130

178

opening in furnace bottom.

Table IV.

tible floor base.

4
4
4
4

4
4

5

HOLE IN

FLOOR

Ì

Figure 4—Floor Opening for Concrete Slab

TABLE IV—OPENING DIMENSIONS

Furnace Casing

Width

14-3/16

17-1/2 16-7/16

21 1 9-7/8

24-1/2

*These dimensions apply when a Model 518A Evaporator Coil casing

is to be installed.

A

13-1/8

23-7/16

Heat-Oniy

19-5/8
19-5/8
19-5/8
19-5/8

В

Heat/Cooi*

20-15/16
20-15/16
20-15/16
20-15/16

—2-

Figure 7—Furnace, Plenum, and

Base Installed on a Combustible Floor

2. Cut and frame hole in floor per dimensions in Table I of
Installation Instructions packaged with combustible

floor base. If this requires cutting of a floor joist, tie
ends of cut joist into adjacent joists so that proper
floor support will be maintained.

3. Assemble and install combustible floor base per

instructions packaged with base.

4. When completed, combustible floor base, plenum, and
furnace (or coil casing when used) should be installed as
shown in Figure 7.

VI. HORIZONTAL ATTIC INSTALLATION

The 376B Furnace can be installed horizontally on either the
LH or RH side. A typical attic installation is shown in Fig
ure 8.

NOTE: The National Fuel Gas Code requires the use of a

type B1 vent in an attic or concealed space.

A. Construct a working platform.

1. Place working platform in location where all required

furnace clearances are obteunable. See Table I.

2. Use materials in platform that will support installer

and service persons.

3. Secure platform to building j oists.

LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS OR FRAMING.'

B. Install furnace

1. Position furnace in desired location.

2. Connect gas supply pipe. See Figure 8 for typical pip
ing entry. It is important to install a sediment trap in
the gas pipe riser.

3. Cormect supply- and return-air ducts.

a. Install field-supplied duct flanges as shown in Fig

ure 9.

b. Using appropriate fasteners for type of supply-air

duct being used, connect duct to furnace.

c. Install field-supplied filter retainers as indicated in

Figure 10 and Table V before connecting retum-air
duct to furnace.

NOTE: For ease of servicing, a return-air filter can be

installed in a common retum-air grille. The air velocity rat
ing must not exceed 300 ft/min for disposable filters. The air
velocity through permanent-type filters shall not exceed the
manufacturer’s recommendation.

d. Using appropriate fasteners for type of duct being

used, connect retum-air duct to furnace.

4. Install 24-x24-in. sheet metal shield on platform in
front of louvered control panel, as shown in Figure 8.

VII. CRAWL SPACE INSTALLATION

The 376B Furnace can be installed horizontally with either
the LH or RH side up. In a crawl space, the furnace can

either be hung from the floor joist or installed on suitable
blocks or pad. The furnace can be suspended from each cor
ner by hanger bolts (Four each 3/8-in. all-thread rod) cut to
desired length, 1 x 3/8 flat washer, 3/8 lockwasher, and 3/8
nut. Dimples are provided for hole locations. See Figure 3.

NOTE: Use Type B1 vent in a concealed space.

The crawl space installation is very similar to the attic;
therefore, refer to Division VI, Section B, steps 1, 2, and 3.
The installation of a sheet metal shield in front of the lou
vered control panel is covered in step 4. For a crawl space
installation, this same sheet metal shield must be installed

SEDIMENT TRAP'

A82178

Figure 8—Typical Attic Installation

—3-

above the louvered control panel. Extend the sheet metal
shield over the furnace top far enough to cover the gas pipe
entry hole.

VIII. FILTER ARRANGEMENT

The two factory-supplied filters are shipped in the blower

compartment. After the return-air duct has been connected
to the furnace, install the filters in a V-formation inside the
return-air plenum. See Figure 10 and Table V for horizontal
applications. See Figure 11 for downflow applications.

TABLE V—FILTER RETAINER

Furnace Casing Width

1 4-3/1 6

17-1/2

21

24-1/2

0

15-3/16

14-1/2

13-9/16

12-1/4

Figure 11—Position of Filters

IX. SEQUENCE OF OPERATION

Using the schematic wiring diagram, Figure 12, trace the
sequence of operation for the heating cycle is as follows;

1. When the blower door is in place, 120 volts is supplied
through blower door interlock switch 9G. Transformer
lA is energized, supplying 24 volts to heating-blower
relay coil 2E, which opens normally closed blower relay
contacts 2E in the low-speed circuit of blower motor
3D.

lA-Transformer, 120-VAC/24-VAC
2D-Relay, Inducer Motor DPST-N. O.
2E-Relay, Heating Blower (HFR) SPST-N. C.
2F-Relay, Cooling Blower (CFR) DPDT

3A-Motor, Inducer
3D-Motor, Blower
4A-Capacitor, Run
5F-Valve, Gas (Redundant)
6C3-Lockout Module (When Used)
6F-Generator, Spark (Solid-State)
6H-Switch, Pilot-Flame Sensing SPOT
7H1-Switch, Limit SPST-N. C.

7H2-Switch, Draft Safeguard (SPST-N. C.) Manual-Reset
7H3-Switch, Auxiliary Limit (SPST-N. C.) Manual-Reset (When

Used)

7P-Pressure Switch-N.O.
7V-Switch, Flow Sensing SPOT

9G-Switch, Blower Door Interlock SPST-N. O.

10B1-Connector, Edge (Furnace Control Board)
10B2-Connector, Edge (Inducer Control Board-7 CKT)
10B3-Connector, Edge (Inducer Control Board-2 CKT)

10B4-Connector, Pilot
10B5-Factory Test Points
10B6-Connector, Blower Motor
11B-Fuse, In Line 2 Amp (When Used)
11C-Link, Fusible (Overtemperature)3 Required
11E-Ground, Equipment
TP-1-Test Point

Factory Wiring, 120-VAC
Factory Wiring, 24-VAC
Conductors on 6C1 (Furnace Control Board)
Conductors on 6C2 (Inducer Control Board)
Screw Terminal for Field Wiring

0

1/4-inch Quick-Connect Terminals

LEGEND

-4—

2. The wall thermostat “calls for heat,” closing the R and
W circuit. This closed circuit supplies power to the 24­volt safety circuit containing Hmit switch 7H1, fusible
link lie, manual-reset draft-safeguard switch 7H2, and
manual reset auxiliary switch 7H3.

3. Simultaneously, the pick coil of gas valve 5F, spark
generator 6F, and inducer-motor relay coil 2D are ener
gized. Inducer-motor relay contacts 2D in the 120-volt
circuit close, starting inducer blower motor 3A. Also,
another set of contacts in inducer-motor relay 2D close
in the 24-volt circuit, and lock in inducer-motor relay
coil 2D. The coil is locked in until the R and W circuit
or safety circuit opens.

4. When the pick coil of gas valve 5F is .energized, gas
flows to the pilot. The pilot gas is ignited by a spark
produced by spark generator 6F. Simultaneously,
inducer motor 3A comes up to speed, actuating flow

sensing switch 7V, energizing the hold coil of gas valve

5F. The pick coil of gas valve 5F and spark generator
6F are deenergized when the contacts of pilot-flame
sensing switch 6H move from the normally closed posi
tion, breaking the circuit to the pick coil and spark gen
erator. In approximately 50 to 60 seconds, the nor
mally open pilot-flame sensing contacts close, making
the circuit to the MGV (Main Operator) of gas valve
5F. Gas valve 5F opens in approximately 10 seconds,
allowing gas flow to the main burners, which are

ignited by pilot 6H. Simultaneously, time-delay circuit

IIL in the blower control center is energized. Approxi

mately 50 seconds after gas valve 5F opens, heating
relay coil 2E is deenergized, which closes the 120-volt
contacts of heating relay 2E, starting blower motor 3D
on its heating speed.

5. When the thermostat is satisfied, the circuit between R
and W is broken, deenergizing gas valve 5F, inducer

motor relay 2D, and the solid-state time-delay circuit

on the printed-circuit board. The gas flow stops imme

diately to the pilot and main burners. After approxi
mately 105 seconds, heat relay 2E is energized and
blower motor 3D stops.

NOTE: After a brief interruption of either electric or gas sup

ply, the furnace will not resume operation until the contacts
of pilot-flame sensing switch 6H move from the normally
open to the normally closed position.

Cooling Cycle

1. The wall thermostat “calls for cooling.”

2. The R, G, and Y circuits are energized. Simultaneously,
the R-and-Y circuit starts the outdoor condensing unit,
and the R-and-G circuit energizes cooling relay coil 2F,
which closes normally open contacts 2F, energizing the
cooling speed winding of motor 3D and opening the

normally closed contacts of cooling relay 2F.

X. ELECTRICAL CONNECTIONS
A. Line-Voltage Wiring

IMPORTANT: Before proceeding with the electrical con
nections, make certain that voltage, frequency, and phase
correspond to that specified on the unit rating plate. Also,
check to be sure that the service provided by the utility is
sufficient to handle the additional load imposed by this
equipment. Refer to the unit rating plate for equipment elec
trical requirements.

in accordance with the National Electrical Code and any
local codes or ordinances that might apply.

Use a separate fused branch electrical circuit containing a
properly sized fuse or HACR-type circuit breaker for this
furnace. A disconnecting means must be located within
sight of, and readily accessible to, the furnace. The blower
door switch may be acceptable in some areas as a discon

necting means.

If fine-voltage wiring to the unit is encased in a nonmetalfic

sheath, connect the incoming ground wire to the grounding
wire inside the furnace J-box. If metallic conduit is used, it
will serve as the ground.

B. Low-Voltage Wiring

Make field low-voltage connections at the low-voltage termi
nal strip. See Figure 15.

NOTE: When the furnace is instedled in the horizontal posi

tion with RH discharge air, low-voltage wire connections
can be made easier by removing the two control box mount
ing screws and letting the control box turn so that the low­voltage screw terminals are visible. Be sure to reinstall the
control box after the connections are made.

NOTE: Use AWG No. 18 “color-coded” copper thermostat

wire for lengths up to 100 ft. Above 100 ft, use AWG No. 16
wire.

IMPORTANT: The thermostat heat anticipation must be set

to match the amp draw of the gas valve and electrical com
ponents in the R-W circuit. Accurate amp draw readings
can be obtained at thermostat subbase terminals R & W.
Figure 13 illustrates an easy method of obtaining the actual
amp draw. The amp reading should be taken after the
blower motor has started.

The room thermostat should be located where it wfll be in

the natureJ circulation path of room air. Avoid locations
where the thermostat would be exposed to cold-air infiltra
tion, drafts from windows, doors, or other openings leading
to the outside, or exposed to air currents from warm- or
cold-air registers; or to exposure where the natural circula
tion 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
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 that could affect
its operation and prevent it from properly controlling the

See Figure 15 for wiring diagram showing the proper field

high- and low-voltage wiring. Make all electrical connections

Figure 13—Amp Draw Check With Ammeter

—5—

room temperature. Any hole in the plaster or panel through
which the wires pass from the thermostat should be ade
quately sealed with suitable material to prevent drafts from
affecting the thermostat.

C. Blower Control Center

Each furnace features a blower control center. This will aid
the installer and serviceperson when installing and servic
ing the unit. A low-voltage terminal board is marked for
easy connection of field wiring. See Figure 14.

XI. STARTUP AND ADJUSTMENT

In addition to the following information, refer to “Proce
dures for Induced-Combustion Gas-Fired Furnaces” pack

aged with the unit.

NOTE: The furnace blower door must be in place to complete

the 115-volt circuit to the furnace.

A. Adjustment of Blower Speed

To change motor speed taps, remove the motor tap lead. See
Table VI. and relocate it on the desired terminal on the
plug-in terminal block/speed selector located on the blower.

TABLE VI—SPEED SELECTOR

Speed

Common
Hi
Med-Hi
Med-Low
Low

Tap No.

C

1

2

3

4

The gas service pressure must not exceed 14 in. wc (8.1
ounces) for natural gas.

NOTE; The gas valve regulator has been factory-set at 3.5

in. wc for natural gas. Refer to “Procedure for Induced­Combustion Gas-Fired Furnaces” for readjusting when
checking input.

yii

- Ì-

Figure 14—Blower Control Center

B. Automatic Gas Control Valve

These units are equipped with an automatic gas control
valve. 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 temper
ature and observing that the main burners light on “call for
heat” (there will be a time delay) and go off when the pointer
is moving below room temperature setting.

NOTE: For ease of adjusting the pilot flame, disconnect and

tape one power lead at the main gas valve. Disconnect ter
minal No. 1. This will pervent main burner ignition and
allow time to adjust the pilot. Reconnect the power lead
after adjustment.

XII. CARE AND MAINTENANCE

- FIELD LOW-VOLTAGE WIRING

Figure 15—Heating and Cooling Application Wiring Diagram a7S46i

—6—

PILOT TUBE REGULATOR

CONN

PILOT J.

ADJUSTMENT

X- .- t.

Figure 16—Redundant Automatic Gas

Control Valve

ADJUSTMENT

-, \:

PRESSURE

TAP

/

For continuing high performance, and to minimize possible
equipment failure, it is essential that periodic maintenance
be performed on this equipment. Consult your local Dealer
as to the proper frequency of maintenance and the availabil

ity of a maintenance contract.
The abihty to properly perform maintenance on this equip

ment requires certain mechanical skills and tools. If you do
not possess these, contact your Dealer for maintenance.

The niinimum maintenance that should be performed on
this equipment is as follows:

1. Check and clean or replace air filter each month or as
required.

2. Check blower motor and wheel for cleanliness and lubri
cation each heating and cooling season. Clean and
lubricate as necessary.

3. Check electrical connections for tightness and controls
for proper operation each heating season. Service as

necessary.

c. Reinstall filters with cross-hatch binding facing

blower.

B. Blower Motor and Wheel

1. Remove blower access panel.

2. Remove vent pipe enclosure.

3. Disconnect vent pipe and remove short piece of pipe
from furnace.

4. Disconnect wires from auxiliary limit on blower
housing.

NOTE: For ease of blower removal, it may be necessary to

remove the control box on some sizes.

5. Remove blower assembly from furnace.

6. Remove motor from blower housing.

7. Lubricate motor using good grade of SAE 20 nondeter
gent motor oil. Put one teaspoon, 5cc, 3/16 oz., or 16 to
25 drops in each oil port.

8. Remove blower wheel from housing and clean by using
vacuum with soft brush attachment. Care must be
exercised not to disturb balance weights (clips) on
blower wheel vanes.

9. Reassemble furnace by reversing above procedures.

When a more detailed servicing procedure is required, see
the furnace Service Manual available from yom Dealer or
Distributor.

C. Cleaning Heat Exchanger

If it becomes necessary to clean the heat exchanger because
of carbon deposits, soot, etc., proceed as follows:

NOTE: Deposits of soot and carbon indicate a problem exists

and needs correcting. Corrective action must be taken to

correct the problem.

1. Turn off gas and power to furnace.

2. Remove control and blower access doors.

3. Remove vent pipe enclosure and disconnect vent pipe
from relief box.

4. Remove four screws that secure relief box to blower
shelf.

5. Disconnect two wires from safeguard switch.

6. Disconnect wire harness edge connector from side of
inducer control box.

A. Air Filter

Each furnace accommodates two filters which are installed
in the return-air duct. See Figures 10 and 11.

To clean or replace the filters, proceed as follows:

1. Disconnect electriceil power before removing access
panel.

2. Remove upper access panel.

3. Reach up behind top plate, tilt filters toward center of
retum-air plenum, remove filters, and replace or clean
as needed.

4. Furnaces are equipped with permanent, washable fil
ters. Clean those filters as follows:

a. Clean with tap water.

b. Rinse and let dry. No oiling or coating of filters is

required.

-I’i

A77007

Figure 17—Dual Blower With Left-Hand

Housing and Wheel Removed.

—7—

7. Remove eight screws that secure flue collector box to
center panel. Use care not to damage sealant.

8. Remove complete inducer assembly from furnace,
exposing flue openings.

9. Remove flue choke.

10. Using field-provided small wire brush, steel spring
cable, reversible electric drill, and vacuum cleaner;
clean cells.

a. Assemble wire brush and steel spring cable.

(1.) Use 4 feet of 1/4-in. diameter high-grade steel

spring cable (commonly known as drain
cleanout or Roto-Rooter cable).

(2.) Use 1/4-in. diameter wire brush (commonly

known as 25-caliber rifle cleaning brush).

NOTE: The items called for in steps 1 and 2 can be pur

chased at a local hardware store.

(3.) Insert twisted wire end of brush into end of

spring cable, and crimp tight with crimping tool
or strike with baU-peen hammer. Tightness is

very important.

(4.) Remove metal screw fitting from wire brush to

allow insertion into cable.

b. Clean each heat exchanger cell.

(1.) Attach variable-speed reversible drill to end of

spring cable (end opposite brush).

(2.) Insert brush end of cable into upper opening of

cell and slowly rotate with drill. Do not force
cable. Gradually insert at least 3 feet of cable
into two upper passes of cell. See Figure 18.

(3.) Work cable in and out of cell three of four times

to obtain sufficient cleaning. Do not pull cable
with great force. Reverse drill and gradually
work cable out.

(4.) Remove burner assembly and flame radiators.

(Identify gas valve leads.)

(5.) Insert brush end of cable in lower opening of

cell, and proceed to clean two lower passes of
cell in same manner as two upper passes.

(6.) Repeat the foregoing procedures until each cell

in furnace has been cleaned.

(7.) Using vacuum cleaner, remove residue from

each cell.

(8.) Using vacuum cleaner with soft brush attach

ment, clean burner assembly.

(9.) Reinstall flame radiators and burner assembly.

Care must be exercised to center the flame radi
ators in the cell openings. Refer to furnace wir
ing diagram when reconnecting gas valve leads.

11. After cleaning flue openings, check sealant on flue col
lector to ensure that it has not been damaged. If new
sealant is needed, contact your Distributor.

12. Reinstall flue choke. Be sure all screws are in place and
tight.

13. Clean and replace flue collector assembly, making sure
all eight screws are secure.

14. Replace four screws that secure the rehef box to blower
shelf.

15. Reconnect two wires to safeguard switch.

16. Reconnect wire harness edge connector to side of

inducer control box.

17. Reconnect vent pipe to relief box, reinstall pipe

enclosure.

18. Replace blower door only.

19. Turn on power and gas.

20. Set thermostat and check furnace for proper operation.

21. Check for gas leaks.

22. Replace control door.

D. Pilot

Check the pilot and clean if necessary at the beginning of

each heating season. The pilot flame should be high enough
for proper impingement of the safety element and to light
the burners. Remove the accumulation of soot and carbon
from the safety element or sensing probe. See Figure 19 and
check electrode position.

E. Electrica! Controls and Wiring

NOTE: There may be more than one electrical supply to unit.

With power disconnected to unit, check all electrical connec
tions for tightness. Tighten aU screws on electrical connec
tions. If any smoky or burned connections are noticed, dis

assemble the connection, clean all parts and strip wire, and
reassemble properly and securely. Electrical controls are dif
ficult to check without proper instrumentation; therefore,
reconnect electrical power to unit and observe unit through
one complete operating cycle. If there are any discrepancies
in the operating cycle, contact your Dealer and request
service.

Figure 18—Cleaning Heat Exchanger Cell

A82181

—8—

^_T

16

Figure 19—Position of Electrode to Pilot