Twinning Kit NAHA003WK.01
For Use With Furnace Models Using
Honeywell ST9120 and ST 9160 Electronic Fan Controls
Please read these instructions completely before attempting installation.
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Electrical shock hazard/Fire and/or explosion haz- ard.
Turn off electric power supply at disconnect switch or service panel before starting installation.
Turn off gas supply at field installed manual gas valve before starting installation.
Failure to follow this warning can result in property damage, personal injury and/or death.
Furnace Installation
Refer to the Installation Instructions packed with the furnaces for information about clearances,
CAUTION
Furnaces installed MUST be identical. They may be installed on a raised platform or wood floor which MUST be level. When side return is required, separate return air drops MUST be made to both furnaces. Do not use rear of furnace for the return air duct connection.
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Installation or repairs made by unqualified persons can result in hazards to you and others. Installation MUST conform with local building codes or, in the absence of local codes, with the National Fuel Gas Code NFPA 54/ANSI A223.1,1990 or latest edition. In Canada, National Standard CAN/CGA
The information contained in this manual is in- tended for use by a qualified service technician fa- miliar with proper safety procedures and equipped with the proper tools and test instruments.
Failure to carefully read and follow all instructions in this manual can result in furnace malfunction, property damage, personal injury and/or death.
This twinning kit is intended to permit two identical gas furnaces to be installed connected to the same duct work. Air conditioning can be added by using one air conditioning evaporator coil sized for the total air flow capabilities of the two furnaces.
Single and Two Stage Heating
Single or two stage heating is obtainable using twinning kit NAHA003WK01. Follow the instructions located in the Twinning Kit Installation section for proper hookup of desired thermostat staging.
CAUTION
Make sure blower motors are wired to operate on the same speed tap.
CAUTION
Two furnaces must be plumbed with a single supply gas shut off valve.
NOTE: When twinning kit has been installed, locate the adhesive backed wiring diagram included in the kit and apply next to the existing wiring diagrams in the furnaces.
TWINNING KIT INSTALLATION
The twinning kit contains (2) 36” wires of two different colors to interconnect the electronic fan controls of the two furnaces. For proper operation, and to avoid damage to the controls, be sure to match Z1 to Z1 and Z2 to Z2 or C to C and H to H on each fan control (see Figure 1 and Figure 2). The wires are color coded to assist with this connection. Each wire is factory terminated with a special crimped edge connector which will push into mating connection positions on the edge of the circuit board on each fan control. The length of these wires can be extended by cutting and splicing sufficient additional wire to each lead.
An isolation relay is provided to protect the system’s thermostat from possible overloading due to the combined valve and control load of the two appliances.
Printed in U.S.A. | 441 06 1003 02 (10/2001) |
