This twinning kit permits connection of two multi-speed constant torque (MCT) ECM, variable-speed constant torque (VCT), fixed-speed constant torque (FCT) ECM, or PSC blower motor equipped furnaces controlled by a mechanical thermostat. An electronic User Interface cannot be used and is not approved for twinned furnaces. This furnace twinning kit permits two of the following furnaces of the same size to operate as a single unit on the same duct work. The furnaces must be installed with common supply and return plenums. For upflow installations, the common return plenum or platform must use some or all of the bottom return opening as shown in the DUCT CONNECTIONS section of the installation manual. This kit ensures both furnace blowers operate simultaneously so air flows through the duct work rather than recirculating in a loop between the furnaces.
