How to test a thermocouple’s voltage using a multimeter. Pilot light keeps going out? A faulty thermocouple may be the issue. Acceptable range for most water heaters is 17-32 mV.
Step 5: Light the pilot, and continue to hold the pilot switch down until maximum voltage is reached. Normal operation for most water heaters is 17-32 mV. If it falls below this range a replacement thermocouple may be needed.
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