Rheem water heater troubleshooting starts with one question: gas or electric? A gas Rheem that won’t heat is usually the pilot, the thermopile or the gas control, and the status light on the knob says which. An electric one is usually a tripped breaker, a tripped high-limit or a burnt element. A repair starts with our $99 diagnostic; a new gas tank is $3,379 to $5,485 installed in Northern Virginia. From about $56 a month at 0% APR for 60 months, the whole price financed, on approved credit.
Every Rheem code, and what each repair costs, is on our Rheem repair page.
Rheem gas water heater not heating: read the status light
| Blinks | What it means |
|---|---|
| 1 blue every 3 seconds | Normal |
| Off or solid | Control off or the pilot is out |
| 2 red | Pilot lit, thermopile voltage low |
| 4 red | High temperature shutdown |
| 5 red | Temperature sensor failure |
| 7 red | Gas control or valve failure |
| 8 red | False pilot flame signal |
From Rheem’s status light sheet. Two blinks is a repair; four, five, seven and eight need a technician.
Rheem electric water heater not heating
Check the breaker first. Then the high-limit, called the ECO: a red reset button behind the upper access panel. Rheem’s manual says once it trips it has to be reset by hand, and that whatever made the water too hot has to be found by a qualified technician, so a reset that holds for a day and trips again is a call. Heating elements can also burn out without warning; one dead element is a tank that runs out fast, two is no hot water at all (Rheem electric manual).
Rheem’s newer smart electrics blink a red light instead: three blinks means it tried to heat without water, four means element wiring or a tripped high-limit.
Not enough hot water, or it runs out fast
Sediment on the bottom of a gas tank takes up room and insulates the water from the burner. A dip tube that’s cracked or degraded mixes incoming cold water into the hot at the top. On an electric tank, one failed element. All three are repairs; a sudden drop on a tank that used to be plenty is a part.
Rumbling, popping or hissing
Rumbling and popping is water trapped under sediment boiling through it. Rheem’s manual recommends draining a few quarts from the bottom every month; most people don’t, and a yearly flush ($199 on its own) is the catch-up. Hissing or sizzling on a gas tank is water dripping onto the burner; on an electric one, a leaking element gasket. Both are worth a look before they get worse.
Leaking, or the relief valve is dripping
Find where it comes from. A dripping relief valve usually means pressure building from thermal expansion (never plug it). A leaking fitting or valve is a repair. Rheem’s own words on water pooling from the tank body: replacement becomes the only safe answer.
Hot water smells like rotten eggs
That’s the anode reacting with high-sulfate water. Rheem’s manual says to pull the anode for inspection yearly and replace it once more than six inches of its core wire shows. A different anode usually ends the smell.
Rheem tankless codes, quickly
| Code | What it means |
|---|---|
| 11 | No ignition: check the gas valve is fully open |
| 12 | Flame lit, then lost |
| 1L | Lime in the heat exchanger: needs a flush |
| 29 | Condensate not draining |
| 90 or 99 | Air intake or vent blocked |
| P1 | Not enough water flow to fire |
IKONIC models add A0 in front (A011, A012). From Rheem’s tankless troubleshooting guide.
Rheem troubleshooting questions people ask us
Why is my Rheem water heater not heating?
Gas: the pilot, thermopile or gas control, and the status light tells you which. Electric: a breaker, the high-limit reset or a burnt element. The diagnostic is $99 and the repair is priced in writing first.
Behind the upper access panel, on the high-limit (ECO) above the thermostat: a red button. Turn the power off at the breaker before you open the panel. If it trips again, call.
How long does a Rheem water heater last?
Rheem says tanks typically last 8 to 12 years and to start planning a replacement around year 10.
Should I repair or replace my Rheem water heater?
Rheem’s rule of thumb: if the repair costs more than half the price of a new heater, replace it. A leak from the tank body means replace. A new gas tank is $3,379 to $5,485 installed. From about $56 a month at 0% APR for 60 months, the whole price financed, on approved credit. The Rheem repair page has every price.
