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13

Vent System Sizing

Refer to the venting tables in the NATIONAL FUEL
GAS CODE, ANSI Z223.1 for details on proper
sizing of the vent system for this furnace. The
furnace is supplied with a three-inch diameter vent
connection. Some models require four inch or five
inch diameter vent pipe. The specification table on
page 2 lists the proper size of vent connector pipe
for each model of furnace. If a vent pipe of more
than three inch diameter is required for the furnace
being installed, the installer must supply a suitable
transition.

Venting into an Existing Chimney

Whenever possible, B-1 metal pipe should be used
for venting. Where use of an existing chimney is
unavoidable, the following rules must be followed:

1. The masonry chimney must be built and

installed in accordance with nationally recog-
nized building codes or standards and must be
lined with approved fire clay tile flue liners or
other approved liner material that will resist cor-
rosion, softening, or cracking from flue gases.
THIS FURNACE IS NOT TO BE VENTED INTO
AN UNLINED MASONRY CHIMNEY.

2.  This furnace may be vented into a fire clay tile

lined masonry chimney only if a source of dilu-
tion air is provided, such as by common venting
with a draft hood equipped water heater. If no
such source of dilution air is available, Type B
vent must be used. The existing chimney may
be used as a chase for the Type B vent.

3.  The chimney must extend at least three feet

above the highest point where it passes through
a roof of a building and at least two feet higher
than any portion of the building within a hori-
zontal distance of ten feet.

4.  The chimney must extend at least five feet

above the highest equipment draft hood or flue
collar.

Inspection of Existing Chimney

1.  Before connecting the vent connector to a

chimney, the chimney passageway must be ex-
amined to ascertain that it is clear and free of
obstructions and must be cleaned if previously
used for venting solid or liquid fuel-burning ap-
pliances or fireplaces.

2.  Clean-outs must be examined to determine that

they will remain tightly closed when not in use.

3. When inspection reveals that an existing

chimney is not safe for this application, it must
be rebuilt to conform to nationally recognized
standards, lined or relined with a suitable liner,
or replaced with a suitable vent or chimney.

Venting with Metal Pipe

Type B (double wall) vents must extend in a gener-
ally vertical direction with offsets exceeding 45
degrees, except that one horizontal run may be
allowed. Any angle greater than 45 degrees from the
vertical is considered horizontal. The total horizontal
run of a vent, plus any horizontal vent connector,
must not be greater than 75% of the vertical height
of the vent. A Type B vent must terminate at least
five feet in vertical height above the highest con-
nected equipment draft hood or flue collar.

Vent Connection

The furnace is supplied with a three-inch diameter
vent connection at the vent blower. For installations
where the vent passes in front of the blower com-
partment (downflow and some horizontal), a two-foot
long section of three-inch diameter single-wall vent
pipe should be used to extend the vent outside of
the furnace casing. This section of the vent pipe may
be installer supplied, or factory accessory part
number 2802-312P may be used. If a transition to
type B vent is to be done, the transition should be
outside of the furnace casing. If a transition to a
larger size vent pipe is required, the transition
should be outside of the furnace casing

Vent Connector Sizing

A vent connector must be sized properly for the
equipment connected to it. The furnace is supplied
with a three-inch diameter vent connection. Some
models require four inch or five inch diameter vent
pipe. The specification table on page two lists the
proper size of vent connector pipe for each model of
furnace. If a vent pipe of more than three inch
diameter is required for the furnace being installed,
the installer must supply a suitable transition. Use
the vent tables in the NATIONAL FUEL GAS CODE,
ANSI Z223.1 to determine the proper vent connector
size.

The vent connector must be as short as possible
and the furnace should be located as close as
practicable to the chimney or vent.

The horizontal run of a vent connector must not be
more than 75% of the height of the vertical portion of
the chimney or vent above the connector.

A vent connector must not pass through any ceiling,
floor, firewall, or fire partition. A single-wall metal
pipe vent connector must not pass through any
interior wall.

Summary of Contents for G8C 50

Page 1: ...RATION 18 FURNACE OPERATION 18 INSTALLATION CHECKS 19 SERVICE INSTRUCTIONS 21 REPLACEMENT PARTS 21 GENERAL INFORMATION These instructions are for the use of qualified individual specially trained and experienced in installation of this type equipment and related system components Installation and service personnel are required by some states to be licensed Persons not qualified shall not install t...

Page 2: ...5521 100 000 21 10 x 10 40 70 1600 170 1 2 4 2804 5521 100 000 24 1 2 2 10 x 6 35 65 2000 165 3 4 4 2805 5521 125 000 24 1 2 2 10 x 6 40 70 2000 170 3 4 5 2805 5521 All models are supplied with 3 vent connections An installer supplied transition to 4 or 5 diameter must be used where necessary A B C D E F G H J 17 1 2 21 24 1 2 16 1 2 20 23 1 2 20 3 8 20 3 8 20 3 8 20 20 20 16 19 1 2 23 14 1 2 18 2...

Page 3: ...staller must conform to all state local and provincial building codes when installing these appliances In the absence of state local or provin cial codes these furnaces and related equipment must be installed in accordance with the latest issue of the following NATIONAL FUEL GAS CODE ANSI Z223 1 NATIONAL ELECTRICAL CODE ANSI NFPA 70 Applicable codes take precedence over any recom mendation made in...

Page 4: ...crews 9 Rotate the vent blower and transition 180 so that its outlet points to the outlet air end of the furnaces as shown in Figure 2 10 Line up the vent blower mounting holes with the holes in the vent pan and screw it into place Use the same machine screws that held the vent blower in place previously 11 Install the two extra machine screws in the two open holes in the front of the vent pan See...

Page 5: ...ound knockout at the right side of the top cap See Figure 5 FIGURE 5 TOP CAP 16 Install the top cap at the opposite end of furnace from the vent blower using the seven sheet metal screws saved earlier See Figure 3 17 Install the bottom cap on the bottom of the furnace using the sheet metal screws saved earlier See Figure 3 18 The conversion is now complete The furnace may now be installed in the d...

Page 6: ...nstallations on Combustible Flooring This furnace may not be installed directly on com bustible materials in the downflow position It may be installed directly on floors made of concrete or other non combustible materials If it is necessary to install the furnace in the downflow position on a combusti ble floor it is required that a combustible sub base be used The part number of the correct sub b...

Page 7: ...UH of furnace input but not less than 100 square inches If all air is from outdoors when communicating directly with the outdoors through vertical ducts the total free area of each opening must be at least one square inch for each 4 000 BTUH of furnace input When communicating directly with the outdoors through horizontal ducts the total free area of each duct must be at least one square inch for ...

Page 8: ...of the following methods shall be used a A plenum type cooling coil must be installed on the air discharge side or b A blower coil type cooling coil must be in stalled in parallel with and isolated from the furnace or c A self contained A C unit must be in parallel with and isolated from the furnace Dampers must be installed when coil blower or self contained unit is employed to pre vent condition...

Page 9: ...ace casing for side return ducts The furnace is supplied with flanges on both ends of the furnace to which the supply and return air ducts may be fastened The casing is embossed on both ends to indicate where to bend the flanges The return air ducts to the furnace must have a total cross sectional area of not less than two square inches per 1000 BTUH of furnace input rating for heating operation I...

Page 10: ...ts concerning gas piping In the absence of local codes follow the recommen dations contained in NATIONAL FUEL GAS CODE ANSI Z223 1 for gas piping materials pipe sizing and the requirements for installation In Canada refer to the latest edition of the CAN CGA B149 Installation Code and local codes for specifics It is recommended that a gas cock shutoff valve be installed in the gas supply line outs...

Page 11: ...11 FIGURE 9 DOWNFLOW CONFIGURATION FIGURE 10 UPFLOW CONFIGURATION ...

Page 12: ...wall venting beginning on page 16 The vent installation shall be in accordance with Part 7 Venting of Equipment of the NATIONAL FUEL GAS CODE ANSI Z223 1 or applicable provisions of the local building codes In Canada for more information regarding vent design and installation refer to the latest edition of the CAN CGA B149 Installation Code 1 This furnace must be connected to a factory built chimn...

Page 13: ...ication it must be rebuilt to conform to nationally recognized standards lined or relined with a suitable liner or replaced with a suitable vent or chimney Venting with Metal Pipe Type B double wall vents must extend in a gener ally vertical direction with offsets exceeding 45 degrees except that one horizontal run may be allowed Any angle greater than 45 degrees from the vertical is considered ho...

Page 14: ...ter the old furnace is removed To test for an oversized vent system the following steps shall be followed with each appliance remaining con nected to the common venting system placed in operation while the other appliances remaining connected to the common venting system are not in operation 1 Seal any unused openings in the common venting system 2 Visually inspect the venting system for proper si...

Page 15: ... separate fused circuit from the main electrical panel should serve only the furnace Electrical Grounding The furnace casing must have an uninterrupted electrical ground in accordance with the National Electrical Code ANSI NFPA 70 or in Canada with the Canadian Electrical Code Part I and CSA C22 1 DO NOT use gas piping as an electrical ground Control Wiring The thermostat should be installed in ac...

Page 16: ...hould be connected to the terminals marked PARK on the blower control board in the furnace control box Motor Terminal Identification Four speed motors White Common Black High Blue Medium High Yellow Medium Low Red Low Three speed motors White Common Black High Blue Medium Red Low MOTOR SPEED TAP SELECTION FOR COOLING COOLING SYSTEM CAPACITY BTUH Furnace Input Blower Wheel 18 000 24 000 30 000 36 0...

Page 17: ...imit circuit Five flashes Rollout switch open Check for open rollout switches loose connections in rollout switch circuit Six flashes One hour pressure switch lockout Pressure switch has cycled four times in a single call for heat Check for vent blockage loose connec tions in pressure switch circuit Seven flashes One hour ignition lockout Burner failed to light in three tries Check gas flow gas pr...

Page 18: ...s present the system will monitor it and hold the gas valve open 6 If the burners fail to light within 6 8 seconds after the gas valve opens the gas valve will close and the ignitor will be turned off After a short pause the system will recycle and try again for ignition If the burners fail to light after three tries the ignition system will lock out The system will re main in lockout mode until o...

Page 19: ...on should also have a manual shutoff valve in the gas piping to the furnace similar to what is shown in Figure 14 To turn off the gas to the furnace use a wrench and turn the switch or lever so that it is pointing 90 degrees from the gas pipe as shown in Figure 14 FIGURE 14 MANUAL GAS SHUTOFF VALVE INSTALLATION CHECKS Checking Gas Input Rate Natural gas heating values can vary widely It is the res...

Page 20: ...rfired condition If it is determined that different orifices are needed please contact your distributor for assistance in selecting the correct replacement Minor Input Adjustment The input may be adjusted slightly by adjusting the pressure in the gas valve in order to change mani fold pressure To adjust pressure regulator remove cover screw See location on Figure 13 on valve Turn adjusting screw c...

Page 21: ...ace any component parts these may be obtained through an authorized dealer who is experienced and can be of assis tance Information on the nearest Distributor may be obtained directly from the company shown on the furnace rating plate Only genuine authorized replacement parts should be used Substitute parts should not be used as they may not be the same in opera tional and safety characteristics F...

Page 22: ...s 9 Ignitor 10 Transformer 11 Furnace Control 12 Pressure Switch 13 Gas Valve 14 Ignitor Bracket 15 Gas Orifice 16 Door Switch 17 Capacitor 18 Blower Wheel 19 Blower Motor 20 Sensor Rod 21 Blower Motor Clamp 22 Rubber Motor Mounts 23 Transition 24 Rollout Switch Bracket 25 Door Latch 26 Pressure Hose 27 Casing Bottom Cap Gasket Package not shown Wire Harness not shown ...

Page 23: ...23 ...

Page 24: ...Subject to change without notice Printed in U S A Copyright by Unitary Product Group 1998 All rights reserved 035 15815 401 9 98 P I Unitary Post Office Wichita Products Box 19014 KS Group 67204 24 ...

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