How to Fix a Rheem Water Heater With No Hot Water

No hot water at any tap points to a lost pilot or ignition on gas units, or a tripped high-limit reset on electric units.

High risk — mains voltage, gas, or refrigerant. Stop and hire a pro if unsure.

Tools

Step 01
Identify the fuel type
A gas heater has a flue pipe out the top and a gas control valve. An electric heater has a power conduit and two access panels on the side.
Step 02
Electric: press the reset
Cut power at the breaker. Remove the upper access panel and insulation, then press the red high-limit reset button until it clicks.
Step 03
Electric: test the elements
With power still off, check each element for continuity with a multimeter. No reading means the element is burned out and needs replacement.
Step 04
Gas: relight the pilot
Follow the label sequence exactly, holding the control knob at Pilot while igniting, then hold 30 seconds before releasing and turning to On.
Step 05
Gas: replace a bad thermocouple
If the pilot dies each time you release the knob, the thermocouple is failing and should be replaced with the matching length.
Step 06
Verify recovery
Set the tank to 120F. Expect hot water at the tap within 30 to 60 minutes. If you smell gas at any point, leave and call the gas utility.

120F. It limits scald risk and saves energy while staying hot enough for household use.