AprilAire Model 8022 — 4-Wire to 3-Wire Cable Interface Manual

The AprilAire Model 8022 is a 4-wire thermostat to 3-wire cable interface — it lets you connect a 4-wire (or more) thermostat over an existing 3-wire cable run by combining two equipment terminal wires through a diode pair, avoiding the need to run an extra wire.

Contents

• 8022 circuit board
• Diode pair
• Wire nut

Specifications

Mounting Location

The 8022 mounts inside the equipment where other control components are located. The diode pair mounts at the thermostat.

Application

Any two thermostat equipment terminals (not 24V hot or common) can be combined with the diode pair and run to the 8022 through a single wire, avoiding the need to run an extra wire. Typical applications:

• Upgrading a mechanical or battery-operated thermostat to a 24-volt or power-stealing AprilAire electronic thermostat
• Bypassing a wire that is broken somewhere inside the wall
• Adding an additional stage of heating or cooling

Wiring Notes

The thermostat terminal connected to the W lead of the diode pair must match the equipment terminal connected to the W terminal on the EQUIP side of the 8022. The thermostat terminal connected to the Y lead of the diode pair must match the equipment terminal connected to the Y terminal on the EQUIP side of the 8022.

Important: R (24V hot) and X (24V common) must be connected directly to the EQUIP side of the 8022 — all other equipment terminals may bypass the 8022.

Do not remove the supplied jumper on the 8022 board unless instructed otherwise.

Manufacturer

Research Products Corporation (AprilAire), P.O. Box 1467, Madison, WI 53701-1467. Toll-Free: 800-334-6011. Fax: 608-257-4357. Document M436701, B2202113 Rev. 1/00.