AprilAire 8022 — 3 to 4 Wire Adapter Installation Guide

Installation instructions for the AprilAire Model 8022 3-to-4 Wire Adapter — used to add a wire to a thermostat installation when additional wiring cannot be run, or to fix a broken wire, or add a common wire to a 4-wire system.

Overview

In applications where additional wiring cannot be run, the 3-to-4 wire adapter can be used to add a wire to the thermostat. The adapter is also used to fix a broken wire, or add a common wire to a 4-wire system (the green and yellow wires of the Diode "Y" may not be connected to the R or C terminal of the thermostat).

Box Contents

• 3 to 4 Wire Adapter — 1
• Diode "Y" — 1
• Wire Nuts — 2

Safety Considerations

Read and follow manufacturer instructions carefully. Follow all local electrical codes during installation. All wiring must conform to local and national electrical codes. Improper wiring or installation may damage the 3-to-4 wire adapter or HVAC equipment.

Signal word definitions: DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies a hazard that could result in personal injury or death. CAUTION is used to identify unsafe practices which would result in minor personal injury or property damage.

Installation

Step 1 — Location

The 3-to-4 wire adapter can be mounted inside the HVAC unit or inside the control box. It should not be installed where the adapter or wiring may be exposed to the elements. The wires running from the adapter are 9" long, so the adapter should be within 9" of the thermostat connections to the HVAC terminal block. If required, mount the adapter with 2 screws (not provided).

Step 2 — Wiring Requirements

• All system wiring must comply with applicable local and national codes.
• All wiring should be color coded per standard recommendations.
• All wiring should be 18–22 gauge, unshielded wire. Maximum distance between the adapter and the thermostat is 100 feet for 18-gauge wire, or 36 feet for 22-gauge wire.

Step 3 — Adapter Wiring

WARNING: Before installing the 3-to-4 wire adapter, turn off all power to the HVAC system. There may be more than one power disconnect. Electrical shock can cause injury or death.

• The BLUE wire of the 3-to-4 wire adapter must always be connected to the BLUE wire of the Diode "Y".
• DO NOT connect the 3-to-4 wire adapter BLUE, GREEN, or YELLOW wires to the R and C terminals of the HVAC unit — damage may result.
• The GREEN and YELLOW wires of the Diode "Y" should be regarded as extensions of the yellow and green wires of the 3-to-4 wire adapter. The YELLOW wire on the adapter must connect to Y on the HVAC unit to control cooling. The GREEN wire on the adapter must connect to G on the HVAC unit to control the fan.
• Use the wire nuts for wire connections to the Diode "Y".
• Do not connect the green and yellow wires of the Diode "Y" to the R or C terminal of the thermostat.

Wiring Diagram — 4 Existing Wires with Adapter (to accommodate a thermostat that requires 5 wires)

Manufacturer

AprilairePartners.com. P.O. Box 1467, Madison, WI 53701-1467. 800-334-6011, Fax: 608-257-4357. ©2016 Aprilaire – A division of Research Products Corporation.