Most Rheem no-heat calls are solved by resetting the red high-limit button on the upper thermostat or replacing a burnt-out heating element. Check your circuit breaker first to ensure the unit is receiving the required 240 volts of power.
Ignore this and you're looking at cold showers until you fix it, period. And if that ECO button keeps popping out every time you push it back in, don't keep resetting it hoping it'll stick. That's usually a shorted element trying to start a fire. I've seen tanks get so hot from a grounded element that the dip tube melted inside. Get it checked out.
OK so here's the deal with Rheem electrics: they're actually pretty solid units, but the elements do wear out, usually somewhere between 8-12 years depending on your water quality. If you've got hard water and never flushed the tank, probably sooner. The good news is parts are cheap and this is one of the more fixable appliance problems out there. Most of the time you're spending $25 on an element, not $1,200 on a new tank.
Most Likely Causes
Based on aggregated repair data, here is the probability breakdown for this error code:
Burnt Heating Element50%
Tripped ECO Switch30%
Failed Thermostat15%
Sediment Buildup5%
Symptoms You May Notice
Absolutely zero hot water coming out of any faucet in the house, no matter how long you run it.
Water gets warm but goes cold after 5-8 minutes, which usually means one element is working but the other one is dead.
That red button on the upper thermostat is sticking out and when you push it in it pops right back out immediately.
The circuit breaker for the water heater trips every time you reset it, sometimes within minutes.
Loud rumbling or popping coming from the tank right before it stopped heating, which is sediment boiling around a failing lower element.
Can you reset a Rheem waterheater to clear the RHEEM-NO-HEAT code?
Turn the circuit breaker all the way off. Pull both access panels and fold the insulation back. Press the red ECO button on the upper thermostat firmly until you feel it click. Replace the insulation and both panels. Flip the breaker back on. Don't touch anything for 45-60 minutes because the tank needs to reheat from scratch. Test hot water at a faucet after that wait before you decide if it worked.
Tools Required for Diagnosis
Phillips #2 screwdriverFlathead screwdriverDigital multimeterNon-contact voltage tester1-1/2 inch element socket wrenchGarden hose for draining tankNeedle-nose pliersTeflon tape
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
ComponentComponent Under Test
Expected Range10–16 ohms
ConditionIf Open (OL) or infinite, replace component.
Frequently Asked Questions
Why does my Rheem water heater reset button keep tripping?
Nine times out of ten it's a shorted heating element. When an element grounds itself to the tank body it can cause the water to overheat, and the ECO switch is doing exactly what it's supposed to do. The way to tell: push the button in and if it immediately pops back out, that's your clue. A good thermostat and good elements means that button should click in and stay put. Test each element with a multimeter by probing one terminal to the element's metal body. Any continuity at all between those two points and it's grounded. Replace that element and your reset button will probably stop tripping.
How do I know if the upper or lower element is bad?
Pretty reliable rule of thumb here. No hot water whatsoever? Probably the upper element or the ECO switch, because the upper element heats first and the thermostat has to pass power down to the lower one after. Running out of hot water way faster than usual, like after one shower instead of three? That's almost always the lower element. I replaced three lower elements last week alone, it's the more common failure because sediment buries it at the bottom and chokes it. Honestly if one is bad just replace both since they're $20 each and they've been running the same number of years anyway.
Can sediment cause a Rheem water heater to stop heating?
Yeah it can. Sediment builds up at the bottom of the tank over the years, especially if you've got hard water, and eventually it completely covers the lower element. That element is now surrounded by mineral deposits instead of water, so it can't shed heat properly and it runs way hotter than it's designed to until it burns itself out. The rumbling and popping sound some people hear is literally water boiling underneath the sediment layer. If you're at that stage, flush the tank. Hook a garden hose to the drain valve at the bottom and run it until the water comes out clear instead of brown and cloudy.
What's the average cost to fix a Rheem water heater that's not heating?
DIY it's pretty cheap honestly. Elements run $15-30 each depending on wattage. A thermostat pair is another $20-30. If you're calling a plumber, plan on $150-300 for labor plus parts. The element socket wrench is the one specialty tool you need and those are about $10 at any hardware store. Given that new tanks run $600-1,200 installed, a $50 DIY repair on a tank under 10 years old that's not leaking is almost always worth doing. The only time I'd say skip the repair and just replace it is if it's over 12 years old or the tank body itself is corroding and weeping water.
Does a Rheem gas water heater have a reset button?
Not like the electric ones do, no. Gas Rheem units have a thermal cutoff near the burner that's usually non-resettable if it blows, and the gas control valve has a status LED that blinks error codes. One blink typically means no pilot detected, two blinks can mean the thermopile voltage is too low to hold the valve open. Start by relighting the pilot, then check the thermocouple, then read those LED blink codes on the valve body itself. The gas control valve can also fail on its own after enough years, those run about $50-80 for the part and it's about a 30-minute replacement once you're comfortable with it.
How long does it take a Rheem water heater to recover after I reset it?
Plan on 45-60 minutes for a standard 40-50 gallon electric to reheat from cold. Gas heaters are faster, usually 30-40 minutes because the BTU input is higher than electric. Don't run a hot water tap to test it after 10 minutes, you're just pulling cold water into the tank and making it take longer. Wait it out. If you reset the ECO button, turned the breaker back on, and an hour later the water is still cold, the reset didn't fix the root cause and you've got more diagnosing to do. Something is still keeping the elements from running.
Models Known to Experience RHEEM-NO-HEAT Errors
This repair applies to most Rheem waterheaters with this error code. Common model numbers include: