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Rheem Error Code 9 flashes (L terminal): L-terminal fault output: Low control voltage (Heat Pump)

Updated · by Aurora Star Tech Inc.

Rheem error code 9 flashes (L terminal) on a heat pump means: L-terminal fault output: Low control voltage. It is also called Rheem diagnostic code 9 flashes (L terminal).

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

Homeowner? What Rheem code 9 flashes (L terminal) means for you

Check, then call Your heat pump is reporting: L-terminal fault output: Low control voltage. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

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) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rheem error code 9 flashes (L terminal) mean?

Equivalent to code 09. Shown on an L-terminal compatible conventional thermostat when the unit is wired 24VAC (non-communicating).

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

Common causes of Rheem code 9 flashes (L terminal)

  • Transformer overloaded
  • Low line voltage
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 9 flashes (L terminal)

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

Other Rheem Heat Pump codes

CodeMeaning
06Compressor open start circuit
6 flashes (L terminal)L-terminal fault output: Open start circuit
07Compressor open run circuit
7 flashes (L terminal)L-terminal fault output: Open run circuit
8 flashes (L terminal)L-terminal fault output: Control mis-operation
09Low secondary (control) voltage
21Low pressure control (LPC) open
27Low line voltage or no line voltage
28High line voltage
29High pressure control (HPC) open
30ICC fuse open
80Low airflow

All Rheem Heat Pump error codes →

Rheem code 9 flashes (L terminal): homeowner questions

What does Rheem code 9 flashes (L terminal) mean?

L-terminal fault output: Low control voltage. Equivalent to code 09. Shown on an L-terminal compatible conventional thermostat when the unit is wired 24VAC (non-communicating).

Is it safe to keep using my heat pump with code 9 flashes (L terminal)?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Rheem code 9 flashes (L terminal) myself?

You can try one reset (power off for 30 seconds, then on). If Rheem code 9 flashes (L terminal) comes back, the cause is still there and a licensed technician should check it.

Who can fix Rheem code 9 flashes (L terminal) 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

Source: Rheem (-)PRL-JEC Heat Pump Installation Instructions, 12.7 Conventional 24VAC Thermostat Control Wiring (L terminal output), 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.

Emergency HVAC Service

647-657-2977