- 01One+ unitary guide
- 02Heat pump settings
- 03Identify the restricted source
Match the equipment document
This page uses the official One+ Reference Guide for Unitary Equipment and Unitary Aux Heater Installation and Setup, retrieved November 13, 2026. It does not cover every Daikin communicating system or a thermostat from another manufacturer.
Two lockouts, two different sources
For the electric-backup configuration in the reference guide, the documented path is Installer Wizard → equipment setup → heat pump → heat pump settings.
| Documented control | What the guide restricts | Guide range / default |
|---|---|---|
| aux heat lockout temp | Auxiliary electric strips above the selected outdoor temperature | −10°F to 75°F, 5°F steps; default 50°F |
| heat pump lockout temp | Heat-pump compressor below the selected outdoor temperature | −20°F to 65°F, 5°F steps; default 15°F |
The reference requires the auxiliary lockout ceiling to be at least 10°F above the compressor lockout floor. Between the lockouts, it describes a backup request when the indoor/setpoint gap is greater than 4°F, with demand-based behavior otherwise. These are descriptions of that document’s electric-backup logic; they are not settings to apply to every climate, dual-fuel system or firmware.
A default is not your target
For example, seeing 50°F on a screen does not prove your installer left a default unchanged, that the sensor is accurate or that backup must be disabled. A different fuel or equipment setup can use different logic. Ask the installer to identify the actual heat source, applicable section and intended commissioning.
Reading a control and recording its current value is different from changing it. This website does not tell you to disable required backup, reduce minimum run time or force concurrent sources. It offers no economic switchover recommendation without the necessary equipment/fuel data.
Emergency Heat and service
The One+ reference describes Emergency Heat appearing after an aux heat source is configured; the mode directly calls that configured source. If the outdoor heat pump cannot operate, ask whether this temporary backup is appropriate. A possible electrical hazard takes priority and is not solved by another heat mode.
A useful service record includes exact model, active mode, full warning, current indoor trend, outdoor conditions and which settings you observed. Do not open equipment panels to find data. Use the mode comparison or the checklist to organize the question.