Error code

Rheem tankless water heater error code 66

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Is 66 on a Rheem tankless water heater an emergency?

Usually not an emergency. If you smell gas, do not touch switches or try to relight anything: leave, and call the gas utility or 911 from outside.

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What 66 means

“Faulty bypass motor.”

— Rheem, Rheem tankless gas water heater Use & Care manual (AP22009 Rev 04), Service Error Code Chart. Codes vary by model: check your tankless water heater’s own manual.

Where 66 fits

In plain words, 66 is about a motor or fan — it did not turn, turned the wrong speed, or the load is unbalanced.

Rheem gives one other motor, fan and spin code for this tankless water heater: 61 (Faulty blower motor).

Next to 66 in Rheem’s table: 61 (Faulty blower motor) and P1 (Not enough water flow to operate the unit).

What to try first

  • Turn the heater off, unplug it for 30 seconds, restart; if it returns, call a technician.

Safety: If you smell gas, do not touch switches or try to relight anything: leave, and call the gas utility or 911 from outside.

How urgent is it?

At least THIS WEEK. fixRAgent treats this code as a this-week repair: the appliance has reported a fault, but the code alone does not point at a safety hazard. This is fixRAgent’s reading, not the manufacturer’s. A photo can raise it — water near wiring, scorch marks, a gas smell — but a code never lowers what the photo shows.

Who to call

Plumber. Have the model and serial numbers from the label ready — a photo of the label works.

Recalls and manuals

Check whether your model is under a safety recall on the U.S. Consumer Product Safety Commission’s site: cpsc.gov/Recalls. Your owner’s manual is on Rheem’s support site; search it with the model number from the label.