Honeywell / Resideo TrueZONE zone panels (HZ322, HZ432): quick sheet

Covers: TrueZONE HZ322 (up to 3 zones, 2-heat/2-cool conventional or heat pump) and HZ432 (up to 4 zones, 3-heat/2-cool) residential forced-air zone panels with a discharge air temperature sensor (DATS).

Single sourceBrands: Honeywell Home, Resideo6 components

Zone thermostats call the panel, the panel opens the matching dampers and runs the equipment. The panel's discharge air sensor stages down or stops equipment when supply air gets near high or low limits. Most service calls are a stuck damper, an undersized damper transformer or a mis-set thermostat.

Safety first

Turn off panel and equipment power before rewiring.
Do not defeat limits to cure a zoning airflow problem.

How it works

Each zone thermostat connects to its own terminal set on the panel. The panel combines the calls and drives the furnace/air handler and outdoor unit from its equipment terminals.

Dampers are 24 VAC: spring-open/power-closed types and power-open/power-close types. Each zone output has a damper VA limit; extra dampers on one zone need a slave damper control relay.

The panel is powered by its own 24 VAC transformer (40 VA and 75 VA accessories are listed). The panel itself draws only a few VA; damper count drives transformer size.

The DATS mounts in the supply duct a few feet downstream of the plenum. On HZ432 it allows staging and protective down-staging near the high and low supply-air limits. Panel LEDs show calls, equipment stages and damper status.

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Official manufacturer documentation

Always confirm values against the tech sheet for the exact model.

Honeywell Home thermostat wiring help

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.Generic part photos (not of this brand): White retro-style refrigerator beside a kitchen sink cabinet by Pavel Danilyuk, Pexels License

Diagnostic guides for this appliance

Guide · Thermostat

Furnace / air handler 3 A low-voltage fuse keeps blowing (finding the 24 V short)

A blown 24 V fuse is a symptom of a short in the thermostat wire, outdoor unit wire or a load (contactor coil, damper, humidifier). Isolate circuits one at a time instead of replacing fuses.

8 steps ~60 minmoderate

Guide · Thermostat

Zoned system: one zone not heating or cooling (damper and zone panel checks)

If only one zone fails, the cause is almost always that zone's damper, actuator, thermostat or wiring, not the furnace or AC. Simulate a call at the panel and check whether the damper actually moves.

8 steps ~45 minmoderate

Guide · Thermostat

Indoor fan won't turn off from the thermostat

Start at the thermostat: fan set to ON instead of AUTO, or a setpoint the system can never reach. If the thermostat is right, the cause is in the equipment: a stuck fan relay, a limit switch keeping the blower on, a shorted G wire or a control board fault.

4 steps ~40 minmoderate

Other thermostats manuals

Manual · Thermostat

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6 components5 common failuresHoneywell Home, Resideo

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Manual · Thermostat

Emerson / Copeland Sensi smart thermostats (Sensi, Sensi Lite, Sensi Touch, Touch 2): quick sheet

Sensi Wi-Fi thermostats: classic Sensi (ST55 style) and Sensi Lite, Sensi Touch (ST75) and Sensi Touch 2. The Sensi brand moved from Emerson to Copeland; support pages live on both domains.

6 components5 common failuresSensi, Emerson, Copeland, White-Rodgers