Indicators of a Faulty Water Heater Thermocouple > 자유게시판

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When a hot water tap drips or the heater doesn't ignite, the culprit is often a faulty thermocouple. This small, metal device sits on the flame of the pilot of a gas water heater and keeps the gas valve open only when the pilot is lit. If it fails, your heater can shut off or even pose a safety hazard. Knowing the warning signs can help you detect problems before they become costly fixes.

1. Pilot Light Goes Out Frequently
The most obvious sign is that the pilot flame repeatedly goes out. A healthy thermocouple generates a small electric current when exposed to heat. That current keeps the gas valve open. If the thermocouple is stuck in a "cold" state, the valve will close, and the pilot will extinguish. You may find yourself continuously relighting the flame.

2. Heater Turns Off Despite Hot Water
After the pilot is lit, the heater should stay on, heating water for the next 20‑30 minutes. If the thermocouple fails, the gas valve will turn off early, even though the water stays hot. You’ll notice the water temperature drop abruptly, and the heater will need to be relit each time.

3. Odd Odors or Loss of Heat
A defective thermocouple can trigger the safety shut‑off, cutting off gas flow. This might produce a slight chemical odor from the gas or, worse, no heat. Should you detect gas or see the thermostat reading far below the set temperature, inspect the thermocouple.

4. Pilot Light Flickers or Appears Dim
If the thermocouple is marginal, the pilot flame may appear weak or flicker. The reason is that the gas valve opens and closes intermittently. The pilot may seem steady, but the control is actually unstable.

5. Variable Water Temperature
If the water temperature swings wildly—sometimes hot, sometimes lukewarm—your thermocouple might be drifting out of calibration. A minor misalignment can make the gas valve open at incorrect times.

6. Physical Damage or Corrosion
Check the thermocouple for visible wear signs. If you find corrosion, cracks, or a broken stem, it can’t generate enough voltage. Over time, the metal can degrade, especially in heaters that sit in damp or humid environments.

7. Pilot Flame Lags Behind Thermocouple Response
Should you turn the pilot flame on manually and the thermocouple fails to respond quickly, it may be stuck. A delayed response usually means the sensor isn’t detecting heat correctly.

8. Error Codes and Warning Lights
Contemporary gas water heaters will often show error codes if the thermocouple fails. A flashing LED or panel code may indicate a "pilot light" or "sensor" problem.

9. Strange Sounds from the Heater
A rattling or clicking noise during startup can suggest the gas valve flicking, another symptom of a failing thermocouple.

10. Repeated Pilot Relighting by a Plumber
If a plumber must relight the pilot repeatedly within a short timeframe, it shows the thermocouple is faulty.

Fixing a Bad Thermocouple
Turn off the gas supply and wait for the heater to cool
Take out the old thermocouple with a wrench or pliers
Look for corrosion or damage; if present, replace it
Wipe down the connection points and pilot flame area
Mount the new thermocouple, aligning the stem to the pilot flame
Restore gas, relight the pilot, and check that the water heater stays on

If you’re uneasy working with gas appliances, contact a licensed plumber
A timely replacement can prevent wasted gas, restore hot water, and 名古屋市東区 エコキュート 交換 keep your home safe