If your Rheem combi boiler is showing error code P1, here's what it means: Low water pressure. This is a moderate fault. The boiler may keep running intermittently, but it should be diagnosed soon to prevent further damage.
Rheem boilers report faults using numeric codes (e.g. 11, 13). Knowing the code helps a technician arrive prepared with the right parts, which usually means a faster, lower-cost repair.
What causes the P1 code?
Error P1 on a Rheem boiler is most commonly caused by one of the following:
- Leak
- Pressure loss
What you can safely check first
- Note the exact code and your boiler's model number
- Check the pressure gauge — low pressure triggers many faults
- Confirm the gas supply is on and other gas appliances work
- Reset the boiler once, per the manual, only if it's safe to do so
- If the code returns, stop and call a licensed technician
Why this needs a licensed technician
Resolving a P1 fault almost always involves the gas, combustion, sensor or pressurized side of the appliance. Under BC's Safety Standards Act, that work must be performed by a licensed gas fitter — and doing it correctly protects your warranty and your safety. We diagnose Rheem boilers, carry common parts, and verify clean combustion before returning your boiler to service.
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Frequently Asked Questions
Fix Your Rheem P1 Fault
Free, no-obligation quotes across Greater Vancouver. CombiBoiler.ca — A division of ROMA Heating Ltd..