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Equipment error code

Rheem code C1

C1 — high pressure alert. The unit shut down because discharge pressure exceeded the high-limit setting.

Equipment
air conditioner
Brand
Rheem
Source checked
2026-03-01

What this code means

C1 — high pressure alert. The unit shut down because discharge pressure exceeded the high-limit setting.

Source: Rheem RA14 Series Split System — Alert Code Table (AP17885) · checked 2026-03-01

Which models show it

Rheem Classic RA14, RA16, Prestige RA20 condensers and Ruud equivalents with Comfort Control alert codes.

What is actually happening

Outdoor unit stops; thermostat may show alert or outdoor LED pattern per install guide.

Is it safe to keep running?

Stop after one C1 event until airflow and fan operation are verified.

Shut it down when

Fan not running, loud compressor noise, or repeated C1.

What a homeowner can safely check

  • Clean indoor filter.
  • Remove debris from outdoor coil.
  • Confirm outdoor fan operation.
  • Check that canvas winter cover is removed from condenser.

When to stop

  • Fan failure.
  • C1 after filter and coil cleaning.

Likely causes ranked

  1. 1. Condenser fan or capacitor failure

    How a tech confirms: Tests fan motor and capacitor; cleans coil.

    Typical repair: $170–$640 · Air Conditioner Repair cost guide

  2. 2. Indoor airflow restriction

    How a tech confirms: Temperature split and static pressure.

    Typical repair: $150–$425 · Air Conditioner Repair cost guide

  3. 3. Refrigerant overcharge

    How a tech confirms: Subcooling analysis; recovery if needed.

    Typical repair: $250–$725 · Air Conditioner Repair cost guide

  4. 4. Failed high-pressure switch

    How a tech confirms: Gauge verification; switch replacement.

    Typical repair: $230–$475 · Air Conditioner Repair cost guide

Is this the end of this unit?

Compressor damage from ignored C1 on Rheem units over 10 years — price outdoor replacement.

How to clear the code

Five-minute off, service airflow, single disconnect reset.

Why clearing is not fixing it: C1 returns when discharge pressure exceeds limit on next run.

Which trade to call

Call a licensed hvac contractor who works on air conditioner equipment. Gas, refrigerant, and combustion faults are not general handyman jobs.

Related codes and symptom guides

More codes from this brand

Symptom guide: Air Conditioner Not Cooling

FAQ

Rheem C1 meaning?
High pressure alert — discharge side over limit.
Ruud C1 same as Rheem?
Yes — sister brand uses the same alert code table on equivalent models.
C1 in heat pump mode?
Can occur in cooling or certain defrost faults — gauges needed.
C1 repair cost?
Typically $150–$725 for airflow, fan, or charge issues.
C1 vs Goodman E1?
Both high-pressure family faults — follow Rheem service literature for C1 specifics.

Source

Source — Rheem RA14 Series Split System — Alert Code Table (AP17885). Checked .