Furnace Twinning Kit: One Thermostat Controls Two HVAC Systems

If you need one thermostat to control two identical HVAC systems, we at HVAC Surplus have your solution! Our Universal Furnace / HVAC Twinning / Paralleling boards do both; you can use these panels in applications with:

• Single Stage applications 1 Heat / 1 Cool
• Multi Stage applications 2 Heat / 2 Cool
• Heat Pump applications 3 Heat / 2 Cool

» TK-400 Refurbished Twinning Kit

» iO HVAC Controls Twinning Kit

Twinning VS Paralleling: What's the Difference?

• When two furnaces (or HVAC units) share the same ductwork, you need to purchase an furnace twinning kit.
• When two furnaces (or HVAC units) have separate ductwork, you need to purchase a furnace paralleling kit. 

Control Up to Four Units with Two Panels

Two panels can be wired together to control up to four HVAC units. The auxiliary terminals on one panel wire to the thermostat terminals on the other. The auxiliary terminals ‘R’ and ‘C’ also provide power to the second panel. The sequence of operation remains the same whereby each HVAC unit’s fan and stages of heating and cooling will be energized at the same time based on the thermostat input.

18 Gauge Thermostat Wire Required
HVAC Surplus offers Made in the USA, high-performance Honeywell Thermostat Wire.
» Click Here to find the thermostat wire you'll need to wire your Universal Furnace Twinning / Paralleling Kit.