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

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

The codes below apply across common Rheem models (Performance, Performance Platinum, ProTerra, Gladiator). 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 water heater error codes

Two distinct systems. (1) GAS TANK models use a status/diagnostic LED on the combination gas control valve that communicates by FLASH COUNT every ~3 seconds (e.g. 1 flash = normal, 2 flashes = thermopile voltage low). (2) HEAT-PUMP/HYBRID (ProTerra/Performance Platinum) and EcoNet/Universal-Connect ELECTRIC models display alphanumeric ALARM/ALERT codes on the LCD or EcoNet app, prefixed 'A' (active alarm, often disables a heat source) or 'T' (transient warning/notice). Codes are read via the control panel: press 'Next' to 'Current Alarm', then the down arrow to scroll active alarms. Note: A-prefix and T-prefix variants of the same number (e.g. A005/T005, A009/T009) describe the same fault as an active alarm vs. a transient warning. Ruud is Rheem's identical sister brand and uses the same codes/displays.

Rheem water heater error codes & what they mean

These are the Rheem water heater 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
1 flash (gas)	Normal Operation – gas control LED flashing once every ~3 seconds indicates the control is powered and operating normally DIY-checkable	Unit is operating normally; no fault present	Confirm you have hot water and the temperature dial is set as desired; No action needed if water is heating normally
2 flashes (gas)	Thermopile Voltage Low – the gas control is not receiving enough voltage from the thermopile/thermocouple even though the pilot may be lit, so the main burner will not stay on pro repair	Weak or failing thermopile; Loose or corroded thermopile connector at the gas control; Dirty, weak, or partially out pilot flame	Check that the pilot is lit and burning a steady blue flame through the sight window; Visually confirm the thermopile lead is plugged firmly into the gas control (do not disassemble); If pilot is out, relight once following the on-tank lighting instructions
4 flashes (gas)	High Temperature Shutdown – the energy cut-off/high-limit has tripped because water temperature exceeded the safe limit; the gas control locks out the burner pro repair	Water temperature set too high; Stuck or faulty gas control allowing overheating; Stacking from very short, frequent hot-water draws	Turn the temperature dial down to a lower setting; Allow the tank water to cool, then attempt a single reset per the on-tank instructions; Do NOT open the gas control or combustion chamber
5 flashes (gas)	Temperature Sensor Failure – the gas control has detected a fault in the water temperature sensor pro repair	Failed or shorted/open water temperature sensor; Damaged sensor wiring or connection; Gas control board fault	Note the flash code and verify by counting the flashes again after the 3-second pause; Attempt a single reset per on-tank instructions; Call a licensed technician – the sensor/gas control is not a homeowner-serviceable part
7 flashes (gas)	Gas Control (Valve) Failure – an internal fault in the combination gas control valve; the control must be replaced pro repair	Internal failure of the combination gas control valve; Control electronics fault	Confirm the flash count after the pause; Set the control to OFF and contact a licensed technician for gas control replacement; Do NOT attempt to open or repair the gas valve
8 flashes (gas)	Flame Sense Error – the control detects a false or unexpected pilot/flame signal (flame sensed when none should be present) pro repair	False flame signal to the gas control; Faulty pilot/flame sensing circuit; Gas control electronics fault	Verify the flash count after the 3-second pause; Contact a licensed technician – flame-sense faults are a safety circuit and not homeowner-serviceable
A004 / T005	Compressor Shutdown: Discharge-Suction Trip / Discharge Temp High – compressor protection has tripped; the unit defaults heating to the electric elements due to a compressor or low-airflow condition pro repair	Low airflow across the evaporator (dirty/blocked air filter or restricted air intake/exhaust); Fan not operating while compressor runs; Refrigerant/sealed-system fault (not field serviceable)	Confirm the air filter/screen is clean and the air intake and exhaust are not blocked; Make sure the unit has adequate clearance and room air supply; Unit will keep making hot water on electric elements; call a technician if the code persists
A005	Compressor Shutdown: Discharge Temperature High – compressor discharge temperature too high; heating defaults to the electric elements due to compressor malfunction pro repair	Low airflow (dirty filter, restricted intake/exhaust); Fan not running while compressor is on; Compressor or sealed-system fault	Clean the air filter and clear any obstructions around the air intake/exhaust; Verify the unit has the required clearance/room volume; Hot water continues via elements; call a technician if it recurs
A006 / T006	Suction Temperature Too Low – heating defaults to the electric elements due to a compressor malfunction pro repair	Low airflow across the evaporator; Low ambient temperature around the unit; Compressor or sealed-system/refrigerant fault	Confirm the air filter is clean and air intake/exhaust are unobstructed; Check that room temperature is within the unit's operating range; Call a technician if the code persists
A008	Detected Dry Fire Condition – insufficient water in the storage tank; the heater is disabled by dry-fire protection to protect the elements DIY-checkable	Tank not fully filled with water (commonly an installation/first-fill issue); Air trapped in the tank; Tank drained for service and not refilled/purged	Confirm the tank is full of water and supply valves are open; Purge trapped air by running a hot-water faucet until water flows steadily; If A008 remains after purging, call a technician
T009 / A009	Compressor wiring may be faulty – heating defaults to the electric elements due to a compressor malfunction pro repair	Loose or faulty compressor/sensor wiring connections; Compressor fault	Note that hot water continues on the electric elements; Do not open the sealed compressor compartment; call a licensed technician to check wiring
A101	Suction Temperature Sensor Failure – heat-pump temperature sensor malfunction; heating defaults to the electric elements pro repair	Failed (open ~ -40 deg / shorted ~ +250 deg) suction thermistor; Loose or damaged sensor wiring; Control board fault	Note the code; hot water continues on the electric elements; Call a technician – sensor/board diagnosis requires a meter and is not homeowner-serviceable
A102	Ambient Temperature Sensor Failure – heat-pump temperature sensor malfunction; heating defaults to the electric elements pro repair	Failed ambient thermistor (open/short); Loose or damaged sensor wiring; Control board fault	Hot water continues on the electric elements; Call a technician for sensor/board diagnosis
A103	Lower Heater Temperature Sensor Failure – lower tank temperature sensor malfunction; the heater is disabled pro repair	Failed lower tank thermistor (open/short); Loose or damaged sensor wiring; Control board fault	Note the code (heater is disabled until corrected); Call a licensed technician – sensor/board diagnosis is not homeowner-serviceable
A104	Upper Heater Temperature Sensor Failure – upper tank temperature sensor malfunction pro repair	Failed upper tank thermistor (open/short); Loose or damaged sensor wiring; Control board fault	Note the code; Call a licensed technician for diagnosis
A105	Evaporator Temperature Sensor Failure – heat-pump temperature malfunction; heating defaults to the electric elements pro repair	Failed evaporator thermistor (open/short); Loose or damaged sensor wiring; Control board fault	Hot water continues on the electric elements; Call a technician for sensor/board diagnosis
A106	Discharge Temperature Sensor Failure – heat-pump temperature malfunction; heating defaults to the electric elements pro repair	Failed discharge thermistor (open/short); Loose or damaged sensor wiring; Control board fault	Hot water continues on the electric elements; Call a technician for sensor/board diagnosis
A107	Water Detected on Floor: Check for Leaks – the leak-detection (drain pan) rope sensor has detected water in the drain pan pro repair	Actual water leak from the tank, fittings, or T&P discharge; Condensate overflow or spilled water reaching the rope/leak sensor; Wet or faulty rope leak sensor	Visually check around and under the heater for water or active leaks; Check the drain pan and clear any standing water; If a leak is found, shut off water supply and call a technician promptly
A108	Condensate Blocked: Unclog Line – condensate drain blockage detected; heating defaults to the electric elements pro repair	Clogged or kinked condensate drain line; Condensate pan overflowing; Faulty condensate sensor	Visually check that the condensate drain line is not kinked or obviously blocked at its outlet; Confirm condensate is being routed to an approved drain; Call a technician to clear internal blockage or replace the sensor
A120 / A121 / A122 / A123	Shut-Off Valve errors – A120 valve can't close, A121 valve can't open, A122 valve inputs in error, A123 valve not installed (only applies to units configured with the leak-detection auto-shutoff valve) pro repair	Shut-off (auto-shutoff) valve wiring loose or disconnected; Valve actuator malfunction; Shut-off valve option not installed but enabled in settings (A123)	If no auto-shutoff valve is installed, on the control panel under the shut-off-valve setting select NO; Otherwise note the code and call a technician to check the valve wiring/connection
A125 / A126	Lower (A125) / Upper (A126) Element Error or Relay Stuck Closed – heating element or control board failure; the heater is disabled pro repair	Failed (open/shorted) heating element; Control board relay stuck closed; Element wiring fault	Note the code (heater is disabled); Call a licensed technician – element/relay diagnosis requires disconnecting power and ohm testing
A127	Element Wire Routing Error – elements mis-wired or control board failure; the heater is disabled pro repair	Heating element wires mis-routed or connected to the wrong terminals (often after service); Loose element/board wiring connection; Control board fault	Note the code; Call a licensed technician – requires power disconnection and wiring/ohm verification
A128 / A129	Lower (A128) / Upper (A129) Element Relay Failure to Close Error – control board relay failure; the heater is disabled pro repair	Control board relay failed to close; Loose element/board wiring connection; Element fault	Note the code (heater is disabled); Call a licensed technician – relay/board diagnosis requires a meter and power disconnection
A130	Unit Off / Air Temp Freezing: Enable Unit – FREEZE WARNING; ambient air temperature around the unit is below freezing so heat-pump operation is suspended DIY-checkable	Surrounding air temperature below the unit's minimum operating temperature; Heater turned off in a cold space	Warm the space to within the unit's operating range; On the control panel, select a heating mode to enable/turn the heater on; No service usually needed if it clears once the area warms
T131	Clean Filter Reminder – routine maintenance notice to clean the air filter (not a fault) DIY-checkable	Scheduled air-filter cleaning interval reached	Set mode to Electric or OFF, remove the air filter and wash it with mild detergent; Dry the filter, reinstall it, and set the unit back to the desired mode; This is a maintenance reminder; no service call needed
T132	Water Heater Difficulty Satisfying Demand – the heater is struggling to keep up with hot-water demand DIY-checkable	Open or running hot-water faucet/fixture; Hot-water leak in the plumbing; Unit undersized for the household demand	Check that no faucets or fixtures are left running; Check for visible hot-water leaks; If none are found, the unit may be undersized – consult a technician
A200	High Water Temp! [ECO] Call Tech Service – the Energy Cut-Off (ECO) high-limit has tripped and the heater is disabled pro repair	Overheating from a stuck element/relay; Failed thermistor causing overheating; Control board fault	Do NOT attempt to reset the ECO yourself; Note the code and call a licensed technician immediately – this is a safety high-limit trip
T300	Water Leak Sensor Not Installed – the water leak sensor is not detected/installed pro repair	Leak sensor not installed; Leak sensor wiring disconnected from the board; Faulty leak sensor	Confirm whether a water leak sensor is installed on the unit; Call a technician to check the sensor wiring/connection if needed
A502 / A503	Time Clock codes – A502 the time clock needs to be programmed; A503 the time clock is not advancing time properly DIY-checkable	Time/clock not set after install or power loss (A502); Internal clock fault (A503)	Set the time/clock on the control panel or EcoNet app (A502); If the clock still won't keep time (A503), call a technician
T504	WiFi Chip Communication Error – the EcoNet/WiFi communication module has a fault (does not affect water heating) DIY-checkable	WiFi/EcoNet module communication fault; Loose module connection	The heater still makes hot water; try power-cycling the unit at the breaker once; If WiFi/EcoNet features remain unavailable, contact Rheem support
A900 / T901 / A902 / A903 / A904 / A905	Controller Fault: Call Tech Service – control board (controller) malfunction; the heater is disabled. The control board must be replaced pro repair	Control board (controller) internal failure	Note the exact code; Call a licensed technician – the control board is not homeowner-serviceable
A906	Power Board Temperature Protection Sensor Failure – the controller/power board is getting too hot pro repair	Power board overheating; Power board temperature-protection sensor fault	Ensure the unit has adequate ventilation/clearance and the area is not excessively hot; Note the code and call a licensed technician

Rheem water heater codes we get called for most

4 flashes (gas) — High Temperature Shutdown – the energy cut-off/high-limit has tripped because water temperature exceeded the safe limit; the gas control locks out the burner

Typical causes include water temperature set too high; stuck or faulty gas control allowing overheating; stacking from very short, frequent hot-water draws. A few things are safe to check yourself (Turn the temperature dial down to a lower setting; Allow the tank water to cool, then attempt a single reset per the on-tank instructions), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 4 flashes (gas) on Rheem water heaters throughout Greater Vancouver.

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

Most Rheem fault codes put the water heater into a safe lockout for a reason. You can safely check the basics — the gas supply on, the pilot light or igniter, the temperature dial setting, the breaker on (power-vent/electric/hybrid models), and no water leaking around the tank — and restart it once. If the code returns, stop and book a technician. If you 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. Never cap or block the temperature & pressure (T&P) relief valve, and don’t keep relighting a pilot that won’t stay lit.

Rheem water heater repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Rheem water heaters — pilot and ignition faults, gas-control (status-light) codes, sensor and thermostat errors, vent and air-intake blockages, leak shut-offs, and (on hybrid/heat-pump and tankless models) control-board and component faults — 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 water heater 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 water heater repair. Explore Water Heater services, browse all water heater error codes by brand, or request a free estimate.

Rheem water heater service areas

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

Rheem water heater error code FAQs

Can I reset my Rheem water heater myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (the gas supply on, the pilot light or igniter, the temperature dial setting, the breaker on (power-vent/electric/hybrid models), and no water leaking around the tank). If the water heater faults again right away, stop and note the code — repeatedly resetting a water heater that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the Rheem 5 flashes (gas) code mean?

On Rheem water heaters, 5 flashes (gas) commonly indicates temperature sensor failure – the gas control has detected a fault in the water temperature sensor. 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 water heaters you didn’t install?

Yes. HeatLand is brand-agnostic and services Rheem water heaters 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 water heater fault code an emergency?

No heat in cold weather is worth treating urgently. If you 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. Never cap or block the temperature & pressure (T&P) relief valve, and don’t keep relighting a pilot that won’t stay lit. For priority water heater repair across Greater Vancouver, call (604) 330-3812.

How much does Rheem water heater 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 Water Heater error-code guides

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