How to Light a Rheem Water Heater Pilot — Step by Step

Modern Rheem gas water heaters (post-2003, FVIR-compliant) have a built-in piezo igniter — no matches required. Older units have a lighting port where you insert a long match. The procedure differs slightly. This page walks through both.

Modern Rheem (post-2003) — piezo igniter procedure

1. Turn the gas control knob to OFF. Wait 5 minutes for any residual gas in the manifold to dissipate.
2. Turn the gas control knob to PILOT.
3. Press and hold down the pilot button (large button — often red, sometimes the knob itself pushes down).
4. While still holding the pilot button, press the igniter button (smaller red or chrome button next to the pilot button). Press it repeatedly — once every 1–2 seconds — until you see the pilot flame through the sight glass.
5. Continue holding the pilot button for 30–60 seconds after the pilot flame is established. This gives the thermocouple time to heat up and signal the gas valve to stay open.
6. Release the pilot button. If the pilot stays lit, success. If it goes out, see troubleshooting below.
7. Turn the gas control knob to ON. The main burner will fire when the thermostat calls for heat (i.e., when the tank water temperature drops below the setpoint).

Older Rheem (pre-2003) — manual match procedure

1. Turn the gas control knob to OFF. Wait 5 minutes.
2. Turn the gas knob to PILOT.
3. Open the burner access door to locate the lighting port
4. Light a long match or BBQ lighter and hold the flame at the pilot tip (visible inside the burner chamber)
5. Press and hold the pilot button with your free hand
6. Once the pilot ignites, remove the match. Continue holding the pilot button for 30–60 seconds.
7. Release the pilot button. Pilot should stay lit.
8. Close the access door, turn the gas knob to ON.

Locating the parts on your Rheem

• Gas control knob: large dial at the front bottom of the unit. Settings: OFF, PILOT, ON. Some Rheem models also have a "RESET" position.
• Pilot button: on or next to the gas control knob. Pressing it manually overrides the safety circuit, allowing gas to flow to the pilot.
• Igniter button: red or chrome button, typically below or next to the pilot button. Each press creates a high-voltage spark at the pilot tip.
• Sight glass: small window in the front access door — lets you see the pilot flame without opening the chamber. Modern FVIR-compliant units always have one.
• Burner access door: front of the unit, held by a single screw or sliding latch. Provides full access to the pilot, burner, and thermocouple.

If the pilot won't light at all

1. Verify gas supply: is the gas valve at the supply line open? Are other gas appliances (range, furnace) working? If gas is off entirely, you can't light a pilot.
2. Check the igniter spark: press the igniter button while watching the pilot through the sight glass. You should see a visible spark at the pilot tip. No spark = igniter assembly failure (see our pilot assembly page).
3. Verify the pilot orifice isn't blocked: debris in the small pilot gas line stops gas flow. Use compressed air to clear, then retry.
4. Check for the audible "click" when you press the pilot button. Some Rheem gas valves make a soft click when the pilot solenoid opens. No click + no flame = gas valve issue.

If the pilot lights but goes out as soon as you release the button

This is by far the most common Rheem issue. The thermocouple (sensor in the pilot flame that signals the gas valve to stay open) has failed in ~80% of cases.

Quick verification: try lighting again, but hold the pilot button for 90 seconds instead of 30. If the pilot still goes out when you release, it's the thermocouple. Replace it — $25 part, 30-minute DIY. See our thermocouple replacement page.

If the pilot lights but the flame is weak or yellow

Weak/yellow flame = poor gas-air mixture at the pilot orifice. Causes:

• Pilot orifice debris — clean with compressed air or a thin wire
• Spider webs in the pilot tube — common in unused units; vacuum the burner chamber
• Pilot tube kinked or damaged — visual inspection; replace if damaged
• Low gas pressure — check other gas appliances; if they're also weak, the gas main is the issue

Yellow flame is a combustion concern — it can produce carbon monoxide. Don't leave a yellow-pilot unit running for extended periods; fix or call a pro.

If the main burner won't ignite (pilot is fine)

Pilot is lit, you turn the gas knob from PILOT to ON, but the main burner never fires:

1. Verify thermostat setting — if set very low, the tank may already be at temperature
2. Turn the thermostat to its highest setting — should hear the burner fire within 30 seconds
3. If still no firing, the gas control valve has failed. See our gas valve page — this is pro-required replacement.

Safety reminders

• Smell gas? Don't light. Close the gas supply, ventilate the area, call your gas utility from outside the house.
• Don't use a lighter near the burner chamber — only the built-in igniter or a long match through the lighting port
• Don't leave the area while attempting to light — if the pilot fails to establish, gas is flowing into the chamber
• If you smell unburned gas after several attempts, stop. Wait 15 minutes, ventilate, try again. If it persists, call a pro — there may be a gas valve issue creating an unsafe condition.

Bottom line

Modern Rheem pilot lighting is 30 seconds: OFF → wait 5 min → PILOT → press pilot button + press igniter button → hold 30–60s → release → ON. If it won't stay lit, the thermocouple is the culprit ~80% of the time. For replacement see our thermocouple page. For broader pilot issues see our pilot assembly page. For complete troubleshooting see our troubleshooting hub.