Rheem Error Code d8: Old shared data (Heat Pump)

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

Rheem error code d8 on a heat pump means: Old shared data. It is also called Rheem diagnostic code d8.

Low severityHeat PumpRheem/Ruud PRL-JEC heat pump (Comfort Control2 ICC)

Homeowner? What Rheem code d8 means for you

Usually minor Your heat pump is reporting: Old shared data. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
In winter, keep snow and ice off and away from the outdoor unit. A short defrost cycle with steam is normal.
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rheem error code d8 mean?

System data on the card/control is obsolete.

Applies to: (-)PRL-JEC 2-stage 16 SEER heat pumps: RPRL/UPRL-024JEC, -036JEC, -048JEC, -060JEC

Common causes of Rheem code d8

Outdated memory card data

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.

Rheem models that use code d8

RPRL-024JEC RPRL-036JEC RPRL-048JEC RPRL-060JEC

Other Rheem Heat Pump codes

Code	Meaning
84	Outdoor ambient temperature sensor fault
90	Communication fault
93	Internal control fault
d1	No shared data
d3	Airflow CFM mismatch
d4	Memory card invalid for device
Flashing c / C / h / H	Anti-short-cycle (3 min) or minimum-run (30 s) timer active
L4	Locked rotor lockout
L6	Open start circuit lockout
L7	Open run circuit lockout
L21	Low pressure control lockout
L29	High pressure control lockout

All Rheem Heat Pump error codes →

Rheem code d8: homeowner questions

What does Rheem code d8 mean?

Old shared data. System data on the card/control is obsolete.

Is it safe to keep using my heat pump with code d8?

Usually yes. Code d8 is normally minor, but if it keeps coming back have it checked.

Can I reset Rheem code d8 myself?

You can try one reset (power off for 30 seconds, then on). If Rheem code d8 comes back, the cause is still there and a licensed technician should check it.

Who can fix Rheem code d8 near me?

Aurora Star Tech Inc. repairs Rheem heat pumps in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

Troubleshooting guides

Heat pump will not defrost / incomplete or excessive defrost Rheem · Heat Pump
Insufficient cooling / pressure problems Rheem · Heat Pump
Outdoor fan runs but compressor does not Rheem · Heat Pump
Outdoor unit will not run Rheem · Heat Pump

Source: Rheem (-)PRL-JEC Heat Pump Installation Instructions, 12.6 ICC Diagnostic Codes, p.31. 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.