Carrier Heat Pump: Outdoor unit unresponsive after several faults

Updated October 13, 2026 · by Aurora Star Tech Inc.

Outdoor unit unresponsive after several faults on a Carrier heat pump: After some combinations of earlier fault codes the outdoor unit can stop responding even though nothing is broken.

Homeowner with a heat pump problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: Carrier Infinity 18VS variable speed heat pump 25VNA8

Common causes of outdoor unit unresponsive after several faults

Control latched after earlier faults

How to fix outdoor unit unresponsive after several faults: step by step

Turn off high voltage to the outdoor unit for at least 2 minutes, then restore power.
Remember the 10-minute sump warm-up delay after power-up (code 68) before full operation.
If the unit still does not respond, troubleshoot with the STATUS light codes.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

If the unit shows an error code, look it up: Carrier Heat Pump codes

Models

Carrier 2-stage 24ANB/25HNB

25HNB624 25HNB636 25HNB648 25HNB660 25HNB924 25HNB936 25HNB948 25HNB960

Carrier Infinity 18VS 25VNA8

25VNA813 25VNA824 25VNA825 25VNA836 25VNA837 25VNA848 25VNA860

Source: Carrier 25VNA8 / 24VNA9 Service Manual, Status Codes note p.14. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.