Rheem Boiler Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your Rheem boiler? This guide explains what the most common Rheem boiler error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed, TSBC-certified gas technicians for Rheem boiler repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common Rheem models (Rheem RTGH (condensing), Rheem RTG / RTGW (non-condensing), Rheem Performance / Performance Platinum tankless, Ruud Ultra / Ruud tankless (sister-brand equivalents), Rheem combi/boiler tankless variants). Meanings follow Rheem’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read Rheem boiler error codes

Rheem and Ruud tankless units display a 2-digit numeric maintenance/error code on the unit's onboard display or, more commonly, on the attached remote-control thermostat (UMC-117 / similar). A few alphanumeric codes (P1, IL) also appear. The code flashes and the unit locks out until reset. Older/PowerVent units may instead signal with red-LED flash counts. The same numeric codes are shared between Rheem and Ruud because the units are mechanically identical sister brands.

Rheem boiler error codes & what they mean

These are the Rheem boiler codes our Greater Vancouver technicians see most. Anything marked pro repair involves gas, electrical, sealed-combustion or control-board work that must be done by a licensed gas technician (TSBC-certified in BC) — never open gas or electrical components yourself.

Code	What it usually means	Common causes	Safe to check yourself
10	Air supply or exhaust (venting) problem / false flame detected — combustion air or venting fault, sometimes reported as flame sensed when burner is off pro repair	Blocked or restricted air intake or exhaust vent; Vent termination obstructed (debris, snow, screen); Loose or disconnected vent joints	Confirm the intake and exhaust vent terminations outside are clear of snow, leaves, nests, or debris; Make sure nothing is leaning against or covering the vent caps; Reset the unit once after clearing any visible blockage
11	No ignition — the burner failed to light pro repair	Gas supply shut off or low gas pressure; Empty propane tank (LP units); Faulty igniter or ignition components	Verify the gas supply valve to the unit is fully open; Confirm other gas appliances in the home are working (rules out a whole-home gas outage); For propane, check the tank is not empty and the tank valve is open
12	Flame failure — flame was established but then lost (flame went out during operation) pro repair	Low or fluctuating gas pressure / undersized gas line; Partially closed gas valve; Empty or low propane supply	Confirm the gas shutoff valve to the unit is fully open; Check propane tank level (LP units); Confirm other gas appliances run normally
13	Improper combustion / flame-rod (poor or improper combustion signal). Common on indoor models pro repair	Dirty or contaminated flame rod; Restricted air intake or exhaust; Dirty/clogged heat exchanger or burner	Check that intake and exhaust vents are not blocked or restricted; Ensure the area around the unit's air intake is clean and unobstructed; Reset the unit once
14	Overheat / thermal-fuse (film-wrap overheat) — a safety limit tripped because the heat exchanger reached an unsafe temperature pro repair	Heavy limescale/mineral buildup on the heat exchanger; Wrong gas type or improper gas pressure causing hot spots; Blocked airflow / restricted venting	Confirm nothing is blocking the air intake or exhaust; Note whether hot-water demand was unusually high or continuous; Reset the unit once — if it returns, stop using and call a technician (overheat is a safety code)
16	Over-temperature warning — outlet water temperature is excessively high pro repair	Scale buildup on the heat exchanger; Faulty outlet thermistor; Restricted water flow	Stop drawing very hot water and let the unit cool; Confirm the temperature setpoint on the remote is reasonable; Reset the unit once
29	Condensate / neutralizer or heat-exchanger outlet temperature fault (condensing models) — temperature too low at the outlet or a blocked condensate path / vent restriction pro repair	Clogged condensate drain or neutralizer; Vent restriction or blockage; Dirty inlet water filter	Check that the condensate drain line is not kinked, frozen, or clogged; Confirm vent terminations are clear; Reset the unit once
31	Inlet (incoming-water) thermistor fault pro repair	Failed or out-of-range inlet thermistor; Scale buildup affecting the sensor; Damaged or loose sensor wiring/connector	Reset the unit once (no homeowner-serviceable parts — sensor replacement is a technician job)
32	Outlet / heat-exchanger thermistor fault pro repair	Failed or out-of-range outlet thermistor; Scale buildup affecting the sensor; Damaged or loose sensor wiring/connector	Reset the unit once (sensor replacement requires a technician)
33	Outlet thermistor fault (hot-water outlet temperature sensor) — on some models 33 is the dedicated outlet sensor pro repair	Failed outlet temperature sensor; Scale buildup; Damaged/loose wiring	Reset the unit once (sensor replacement requires a technician)
34	Combustion-air (ambient) thermistor fault pro repair	Faulty ambient/air thermistor; Blocked air intake or moisture on the sensor; Damaged/loose wiring	Confirm the air intake is clear and the unit is not exposed to excessive moisture; Reset the unit once
35	Thermistor wiring/connection fault — a thermistor is improperly connected or wired pro repair	Loose, reversed, or incorrectly installed thermistor connector; Wiring damage; Recent service left a connector unseated	Reset the unit once (wiring service requires a technician)
51	Gas solenoid valve fault — gas inlet solenoid valve circuit problem pro repair	Faulty gas control/solenoid valve; Damaged or loose valve wiring/connector; Control board fault	Reset the unit once (gas-valve service is technician-only — do NOT open the gas valve assembly)
52	Modulating (proportional) solenoid valve fault — the gas-flow modulating valve is out of range pro repair	Faulty modulating gas valve; Loose or damaged wiring to the modulating valve; Control board fault	Reset the unit once (gas-valve service is technician-only)
61	Combustion fan (blower motor) failure — fan not running at the commanded speed pro repair	Failed or seized fan motor; Obstructed fan shaft / debris; Dust accumulation	Confirm air intake/exhaust are clear; Reset the unit once (fan replacement requires a technician)
65	Water-flow control valve fault (flow-adjustment / water-volume control assembly) pro repair	Faulty water-flow control valve or actuator; Loose wiring to the flow control; Debris affecting the assembly	Reset the unit once (internal valve service requires a technician)
66	Water-bypass / flow control fault — similar to code 65; bypass servo or water-control malfunction pro repair	Faulty bypass/water-control valve; Wiring fault; Debris in the assembly	Reset the unit once (internal valve service requires a technician)
71	Gas inlet solenoid valve circuit fault (solenoid valve drive problem) pro repair	Damaged or improperly installed solenoid valve wiring; Faulty gas valve; Control board fault	Reset the unit once (gas-valve service is technician-only)
72	Flame-sensing device fault — flame detected when it should not be, or flame-rod sensing problem pro repair	Contaminated or faulty flame rod; Flame-rod wiring fault; Gas valve leaking by / control fault	Reset the unit once (flame-rod service requires a technician)
76	Communication fault with the remote control / control board communication error pro repair	Loose or damaged remote-control wiring; Faulty remote control; Moisture or corrosion at connectors	Check that the remote-control cable is securely connected at both ends (if accessible without tools); Reset the unit once
79	Combustion-fan current fault — fan motor drawing abnormal current, often from condensation/moisture pro repair	Condensation or moisture on the fan motor; Failing fan motor; Wiring fault	Reset the unit once (fan service requires a technician)
90	Blocked flue / venting obstruction — exhaust or combustion system blocked pro repair	Blocked or restricted exhaust vent or termination; Excessive vent length / improper venting; Dirty heat exchanger restricting flow	Confirm the exhaust vent termination outside is completely clear; Make sure nothing has fallen against or covered the vent; Reset the unit once
92	Neutralizer abnormality — the condensate neutralizer is near end of life and requires replacement (condensing models) pro repair	Spent / saturated condensate neutralizer media; Condensate system maintenance overdue	No safe homeowner fix — schedule neutralizer replacement with a technician; unit may continue running but should be serviced
P1	Low water flow rate — flow dropped below the minimum activation rate (approximately 0.66 GPM) needed to fire the burner DIY-checkable	Low household water pressure; Clogged inlet water filter screen; Partially closed water valves	Confirm the water shutoff valves to the unit are fully open; Check that faucet aerators and showerheads are not clogged; Verify household water pressure is normal (other fixtures)

Rheem boiler codes we get called for most

11 — No ignition — the burner failed to light

Typical causes include gas supply shut off or low gas pressure; empty propane tank (lp units); faulty igniter or ignition components. A few things are safe to check yourself (Verify the gas supply valve to the unit is fully open; Confirm other gas appliances in the home are working (rules out a whole-home gas outage)), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 11 on Rheem boilers throughout Greater Vancouver.

12 — Flame failure — flame was established but then lost (flame went out during operation)

Typical causes include low or fluctuating gas pressure / undersized gas line; partially closed gas valve; empty or low propane supply. A few things are safe to check yourself (Confirm the gas shutoff valve to the unit is fully open; Check propane tank level (LP units)), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 12 on Rheem boilers throughout Greater Vancouver.

P1 — Low water flow rate — flow dropped below the minimum activation rate (approximately 0.66 GPM) needed to fire the burner

Typical causes include low household water pressure; clogged inlet water filter screen; partially closed water valves. A few things are safe to check yourself (Confirm the water shutoff valves to the unit are fully open; Check that faucet aerators and showerheads are not clogged), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes P1 on Rheem boilers throughout Greater Vancouver.

14 — Overheat / thermal-fuse (film-wrap overheat) — a safety limit tripped because the heat exchanger reached an unsafe temperature

Typical causes include heavy limescale/mineral buildup on the heat exchanger; wrong gas type or improper gas pressure causing hot spots; blocked airflow / restricted venting. A few things are safe to check yourself (Confirm nothing is blocking the air intake or exhaust; Note whether hot-water demand was unusually high or continuous), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 14 on Rheem boilers throughout Greater Vancouver.

Is it safe to keep running a Rheem boiler with a fault code?

Most Rheem fault codes put the boiler into a safe lockout for a reason. You can safely check the basics — gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps) — and restart it once. If the code returns, stop and book a technician. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911.

Rheem boiler repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Rheem boilers — ignition faults, flame and sensor errors, low-pressure and pump problems, fan and flue faults, and control-board issues — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your boiler is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency boiler repair. Explore Boiler services, browse all boiler error codes by brand, or request a free estimate.

Rheem boiler service areas

We repair Rheem boilers across Greater Vancouver and the Fraser Valley, including:

Rheem boiler error code FAQs

Can I reset my Rheem boiler myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps)). If the boiler faults again right away, stop and note the code — repeatedly resetting a boiler that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the Rheem 11 code mean?

On Rheem boilers, 11 commonly indicates no ignition — the burner failed to light. Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed, TSBC-certified gas technician. HeatLand fixes this across Greater Vancouver.

Do you repair Rheem boilers you didn’t install?

Yes. HeatLand is brand-agnostic and services Rheem boilers throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a Rheem boiler fault code an emergency?

No heat in cold weather is worth treating urgently. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. For priority boiler repair across Greater Vancouver, call (604) 330-3812.

How much does Rheem boiler repair cost in Vancouver?

It depends on the fault. Many Rheem codes point to sensors, ignition or pump parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Boiler error-code guides

HeatLand repairs every major boiler brand across Greater Vancouver. More brand guides: