Pilot goes out as soon as you release the button
You can light it, but the flame dies the moment you stop holding the control down.
Start here: Start with the pilot flame shape and whether it is heating the thermocouple tip directly.
Water Heater Troubleshooting
Rheem Water Heater Pilot Won’t Stay Lit
Direct answer: If the pilot lights and then drops out, the most common causes are a weak pilot flame, a dirty pilot opening, a draft blowing the flame off the sensor, or a failing thermocouple. Start with the visible flame and venting checks before assuming the gas control is bad.
Most likely: On a standing-pilot gas water heater, the pilot flame usually is not wrapping the thermocouple the way it should, either because the pilot assembly is dirty or the flame is being disturbed.
This problem has a pretty repeatable pattern in the field. If the pilot lights only while you hold the button, or it stays on for a minute and then quits, look hard at the pilot flame itself, the area around the burner, and anything that could be starving or blowing out that flame. Reality check: a bad thermocouple is common, but it is not the only reason a pilot will not hold. Common wrong move: swapping parts before checking for a dirty pilot or a vent draft problem.
Don’t start with: Do not start by replacing the gas valve or taking apart gas piping. Those are higher-risk moves and they are not the usual first fix.
If the pilot will not light at all,this page is not the best fit; you are dealing with ignition or gas supply, not just a pilot that will not stay lit.
If you smell gas, hear hissing, or see scorch marks,stop and call the gas utility or a qualified service tech before doing anything else.
Last reviewed: 2026-04-17
What the pilot is doing tells you where to start
Pilot stays on briefly, then drops out
The pilot seems normal at first, then goes out after several seconds or a few minutes.
Start here: Look for a weak flame, dirty pilot opening, or a draft issue around the burner compartment and vent.
Pilot goes out when the main burner tries to fire
The pilot holds until the heater calls for heat, then the flame becomes unstable or everything shuts down.
Start here: Check for venting problems, burner compartment air issues, or a pilot flame that is too weak to stay stable during burner operation.
Pilot outage keeps coming back after relighting
You relight it successfully, get some hot water, then find it out again later.
Start here: Focus on intermittent draft, a marginal thermocouple, or debris in the pilot assembly rather than a one-time lighting mistake.
Most likely causes
1. Dirty pilot opening or pilot assembly
A partially blocked pilot makes a small lazy flame that will light but does not fully engulf the thermocouple.
Quick check: Watch the pilot through the sight opening. The flame should be steady and should wrap the thermocouple tip, not barely touch it.
2. Failing water heater thermocouple
If the flame looks decent but the pilot still drops out when you release the button, the thermocouple may not be generating enough signal to hold the safety magnet open.
Quick check: Confirm the thermocouple tip sits in the hottest part of the pilot flame and is not bent away or heavily sooted.
3. Draft or venting disturbance
A backdraft, downdraft, or air movement at the burner opening can pull the pilot off the thermocouple or snuff it out after ignition.
Quick check: Notice whether the flame flickers hard, leans, or changes when nearby doors open, exhaust fans run, or the burner compartment cover is moved.
4. Weak gas flow to the pilot or failing gas control safety hold
This is less common than dirt or thermocouple trouble, but it shows up when the pilot flame stays weak even after cleaning and setup checks.
Quick check: If the pilot flame remains small and unstable after basic cleaning and there are no obvious draft issues, the problem may be beyond simple DIY.
Step-by-step fix
Step 1: Make sure you are dealing with a hold problem, not a no-light problem
A pilot that never lights points you in a different direction than a pilot that lights and drops out.
- Set the thermostat to its lowest setting so the main burner is not trying to fire while you test.
- Follow the lighting instructions on the heater label exactly and watch what happens.
- Note whether the pilot lights cleanly, whether it stays on only while the button is held, or whether it goes out later on its own.
- Look and smell around the heater for gas odor, scorch marks, melted wiring, or signs of rollout near the burner area.
Next move: If the pilot now lights and stays on normally, monitor it through a full heating cycle before calling it fixed. If it still drops out, move to the flame and airflow checks before assuming a bad control.
What to conclude: You are confirming the exact failure pattern so you do not chase the wrong part.
Stop if:
- You smell gas at any point.
- You see soot, scorching, or flame outside the normal burner area.
- The lighting instructions on the unit do not match what you are seeing and you are not sure how to proceed.
Step 2: Check the pilot flame shape and the thermocouple position
This is the fastest way to separate a dirty or weak pilot from a deeper control problem.
- View the pilot through the access opening or sight glass while the pilot is lit.
- Look for a steady blue flame that reaches and wraps the thermocouple tip.
- If the flame is tiny, split, yellow, or dancing around, note that before touching anything else.
- With the gas off and the area cooled down, inspect whether the thermocouple tip is sitting where the pilot flame should hit it and whether it is covered in soot.
Next move: If you find the flame was not hitting the thermocouple and a simple repositioning or cleanup restores a strong wraparound flame, the pilot may hold normally again. If the flame still looks weak or unstable, continue to the pilot opening and draft checks.
What to conclude: A healthy pilot must heat the thermocouple directly. If it does not, the safety circuit will drop the pilot even though the flame initially lights.
Step 3: Clean obvious debris from the burner compartment and pilot area
Dust, lint, rust flakes, and spider-web debris are common reasons a pilot flame goes weak on gas appliances.
- Turn the gas control to off and let the burner area cool fully.
- Remove the outer access cover if your heater has one, but do not disassemble gas tubing or the gas valve.
- Vacuum loose dust and lint from the burner compartment opening and around the base of the heater.
- If the pilot opening is visibly dusty and accessible without disconnecting gas parts, gently clear loose debris from around it with a soft brush or compressed air used lightly from a safe distance.
- Reassemble the cover, relight the pilot, and compare the flame to what you saw before.
Next move: If the flame becomes stronger and steadier and the pilot now stays lit, you likely had a dirty pilot or restricted combustion air path. If the flame is still weak or the pilot still drops out, check for draft and vent trouble next.
Step 4: Look for draft, vent, and combustion-air problems
A pilot can look fine for a moment and still fail if air movement pulls it off the thermocouple or the vent is not drafting correctly.
- With the pilot lit, watch whether the flame leans, flutters, or changes when nearby doors open or close.
- Temporarily turn off strong exhaust devices nearby, like a bath fan, range hood, or dryer, and see whether the pilot behavior changes.
- Inspect the vent connector above the heater for loose joints, heavy rust, sagging sections, or obvious blockage signs.
- Check that the area around the heater is not packed with storage, insulation, or debris that could affect combustion air.
- If your heater uses a sealed burner door or screen, make sure the cover is installed correctly and not bent or blocked.
Next move: If the pilot becomes stable only after correcting airflow around the heater, the root problem is draft or combustion air, not the thermocouple alone. If the flame is properly aimed, the area is clean, and there is no obvious draft issue, the thermocouple becomes the most likely DIY repair path.
Step 5: Replace the thermocouple only if the flame is good and the pilot still will not hold
Once the pilot flame is strong, steady, and hitting the sensor correctly, a weak thermocouple is the most common remaining homeowner-level fix.
- Shut off the gas supply to the water heater and let the burner area cool.
- Use the correct replacement water heater thermocouple for your heater style and length, matching the old one carefully.
- Install it without kinking the line, route it the same way as the original, and place the tip back in the pilot flame path.
- Relight the pilot and hold the control as directed on the heater label, then release and watch for a stable hold.
- If the new thermocouple does not solve it and the flame is still good, stop there and schedule service for gas control or deeper combustion diagnosis.
A good result: If the pilot now stays lit through a full burner cycle and remains lit later, the old thermocouple was likely too weak to hold the safety magnet.
If not: If a good flame and a new thermocouple still do not hold the pilot, the remaining causes are usually gas control failure, pilot assembly issues that need disassembly, or venting problems that need a pro.
What to conclude: This narrows the problem to the safety hold circuit or gas control side once the flame itself has been ruled in as healthy.
Replacement Parts
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FAQ
Why does the pilot stay lit only while I hold the button down?
That usually means the safety circuit is not being satisfied. Most often the pilot flame is too weak or not hitting the thermocouple correctly. If the flame looks healthy and properly aimed, the water heater thermocouple is the next likely suspect.
Can a dirty pilot really make the water heater shut off?
Yes. A little dust, rust scale, or spider-web debris can shrink or distort the pilot flame enough that it no longer heats the thermocouple properly. That is why a flame check and light cleaning come before parts.
Is the gas valve usually the problem?
Not usually. Gas control failure does happen, but it is lower on the list than a weak pilot flame, dirty pilot assembly, draft trouble, or a failing thermocouple. On a gas water heater, you want those ruled out first.
What should the pilot flame look like?
You want a steady blue flame that reaches the thermocouple tip and wraps it well. A tiny flame, a yellow lazy flame, or one that flickers hard and pulls away from the sensor is not right.
When should I call a pro instead of replacing the thermocouple myself?
Call for service if you smell gas, see soot or scorching, suspect venting trouble, or still cannot keep the pilot lit after confirming a good flame and installing the correct thermocouple. At that point the problem is often in the gas control, pilot assembly, or combustion setup.