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How to replace thermopile on A.O. Smith gas water heater?

Replacing the thermopile on an A.O. Smith gas water heater is a relatively simple task that can be done with basic tools and a new thermopile. The thermopile is a crucial component that generates electrical voltage to power the gas control valve and pilot light. If you're experiencing issues with the pilot light not staying lit or the water heater not heating correctly, replacing the thermopile may solve the problem. Here's a step-by-step guide on how to replace the thermopile on an A.O. Smith gas water heater:

1. Safety Precautions:
Safety should always be a top priority when working with gas appliances. Before starting any work, turn off the gas supply to the water heater at the gas shut-off valve and shut off the power to the heater at the circuit breaker or disconnect switch.
2. Gather the Necessary Tools and Materials:
You'll need several tools and materials for this task, including a wrench or adjustable pliers, a screwdriver set, a replacement thermopile compatible with your A.O. Smith water heater model, and a pipe fitting brush.
3. Identify the Existing Thermopile:
Locate the existing thermopile on the water heater. It is usually positioned near the pilot light and is connected to the gas control valve with a lead wire.
4. Disconnect the Lead Wire:
Carefully disconnect the lead wire from the thermopile by removing any screws or fasteners holding it in place. You may need to use a screwdriver or pliers for this step.
5. Remove the Thermopile from the Pilot Assembly:
Use a wrench or adjustable pliers to carefully loosen and remove the thermopile from the pilot assembly. Be gentle to avoid damaging any surrounding components.
6. Prepare the New Thermopile:
Ensure that the replacement thermopile is the correct type and model for your A.O. Smith water heater. Inspect the thermopile to confirm that it is in good condition and comes with any necessary connectors or adapters.
7. Install the New Thermopile:
Position the new thermopile in the same location as the old one within the pilot assembly. Thread it into place and use a wrench or pliers to securely tighten the connection. Ensure that it is snug but not over-tightened to prevent damage.
8. Reconnect the Lead Wire:
Reconnect the lead wire to the new thermopile by securing it with any screws or fasteners that were removed during the disconnection.
9. Perform a Leak Test (Optional):
While it's not necessary for the thermopile replacement itself, you can perform a gas leak test to ensure there are no gas leaks around the connections. Apply a soapy water solution to the thermopile and gas control valve connections and check for any signs of gas bubbles. If you detect a leak, shut off the gas supply immediately and recheck the connections.
10. Restore Gas and Power:
Turn on the gas supply to the water heater at the gas shut-off valve and restore power to the heater by flipping the circuit breaker or reconnecting the disconnect switch.
11. Test the Water Heater:
Wait for the water heater to heat the water. Test hot water at a tap to ensure it reaches the desired temperature. Monitor for any issues or unusual behavior during the initial operation.
12. Regular Maintenance:
To ensure the continued proper operation of your water heater, incorporate regular maintenance into your water heater care routine. Periodically inspect the thermopile and other components for signs of wear, damage, or malfunction, and replace them as needed.

Replacing the thermopile on an A.O. Smith gas water heater is a maintenance task that can help resolve issues related to the pilot light and gas control. If you are not confident in your ability to perform this replacement or encounter any difficulties during the process, it's advisable to seek the assistance of a qualified plumber or technician to ensure the job is done safely and effectively. Proper maintenance of your water heater and its components is essential for a reliable and efficient hot water supply.
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