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AGATWNPME01B: Installation Instructions
SECTION 3
CONNECT ELECTRICAL COMPONENTS
WARNING
!
UNIT DAMAGE AND FIRE HAZARD
Failure to follow this warning could result in fire, personal injury or
death.
Make no connections between the R 24-VAC connection in one furnace
and the R 24-VAC connection in other furnace.
See Electrostatic Discharge Precaution Section.
NOTE: All electrical power connections must be made through exposed
outer side of each furnace. Do not common connect any connection
other than supply- and return-air ducts.
• Side-by-side furnaces in the upflow and downflow position, the LH
furnace line voltage connections must be made on the left side of the
furnace. The RH furnace line voltage connections must be made on
the right hand side of the casing.
• Horizontal back-to-back installations, electrical connections should be
made on the sides of the furnace facing up.
• Upflow and downflow back-to-back installations can use either side
of the furnace for line voltage electrical connections.
115-VAC Connections to Furnace
Each furnace shall be connected to its own 115-VAC power supply. The
twinning kit installation interconnects the furnaces, allowing them to
operate as a single furnace. The L1 (black) connection to each furnace
must be connected to circuit breakers connected to the same service
panel 115-VAC phase leg.
WARNING
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury or death,
or property damage.
Before installing, modifying, or servicing system, main electrical
disconnect switch must be in the OFF position and install a lockout tag.
There may be more than one disconnect switch. Check accessories and
cooling unit for additional electrical supplies that must be shut off
during furnace servicing. Lock out and tag switch with a suitable
warning label. Verify proper operation after servicing.
NOTE: If the furnaces are not connected to the same phase leg of the
electrical power supply, the furnaces will not operate properly.
• On single-phase (residential) systems, each furnace circuit breaker
should be located directly across from each other in service panel, or
each furnace circuit breaker should be located on the same side of
service panel, but must skip one space to be connected to the same leg
of the single-phase power supply.
• On 3-phase (commercial) systems, each furnace circuit breaker should
be located directly across from each other in service panel, or each
furnace circuit breaker should be located on the same side of service
panel, but must skip two spaces to be connected to the same leg of the
3-phase power supply.
The proper 115-VAC phasing of furnace connections permits 24-VAC
transformer phasing as described below.
Phasing of the connected 24-VAC transformer secondary circuits can be
determined with the LED status of both furnaces.
See furnace Installation, Start-Up, and Operating Instructions and status
code labels on blower doors. The furnaces' transformers' black leads
should be connected to L1 connectors and white leads to L2 connectors
on controls. If one or both LEDs are rapidly flashing after installation of
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
this twinning kit, disconnect the ABCD terminal of LH furnace and
observe LED at each furnace.
To verify that the furnaces are in phase, check from Main furnace L1 to
Secondary furnace L1 with a voltmeter. If the furnaces are in phase, the
voltage potential between both furnaces will be ZERO.
If:
a. Both LEDs are on continuously: System phasing is okay.
b. One or both LEDs are rapidly flashing:
(1.) Line voltage polarity is reversed.
(2.) Furnace(s) are not grounded
(3.) Transformer polarity is reversed.
c. One LED is off, one LED is on continuously:
(1.) The 24-VAC circuit is inoperative on furnace with LED
light off.
(2.) Check transformers, auxiliary limits, and door switches in
both furnaces and correct problem.
(3.) Reconnect lead at ABCD terminal of LH furnace and
observe LED at each furnace. The LEDs will glow steady
for proper phasing.
TWINNING KIT HARNESS CONNECTIONS
NOTE: There are three harnesses included in this kit. If the furnaces are
side-by-side, only the Main and Secondary harnesses are required. If the
furnaces are installed back-to-back, the extension harness included in the
kit must be used.
Extension harness is shown in
To install the Extension harness on back-to-back furnace, follow the
steps in
Fig.
17. For other orientations, omit this step.
The Main furnace end of the harness is identified by a white label
marked "MAIN" on the label near the end of the extension harness. The
Secondary furnace end of the harness is identified by a white label
marked "Secondary" on the label near the end of the extension harness.
1. Verify the knockouts are removed from the same side of each
furnace blower compartment.
2. Remove the locknut from each end of the 1/2 in. BX connector
3. Route the 4-pin plug, the 2-pin plug, and three wires of the Main
furnace end of the Extension harness one at a time through the
knockout into the Main furnace blower compartment.
4. Insert the plugs and wires through the locknut of the 1/2 in. BX
connector and tighten the locknut on the BX connector.
5. Route the 4-pin plug, the 2-pin plug, and three wires of the
Secondary furnace end of the Extension harness one at a time
through the knockout into the Secondary furnace blower
compartment.
6. Insert the plugs and wires through the locknut of the 1/2 in. BX
connector and tighten the locknut on the BX connector.
12
Fig.
17.
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