How to Repair a Leak in a Hot Water Boiler

Written by louis gutierrez
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How to Repair a Leak in a Hot Water Boiler
Repair small leaks to avoid a costly tank replacement (plumbing image by Inger Anne Hulbækdal from

Ignoring a leak for too long can result in damage to your hot water boiler, which could lead to you replacing the whole tank. This can be avoided by repairing small leaks yourself. Your water heater can leak from various places. If your tank is leaking from the valve or pipes, you can fix it yourself.

Skill level:

Things you need

  • Adjustable wrench

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  1. 1

    Check the drain valve for leaks. The drain valve is the valve that is usually located near the bottom of the tank. Tighten the valve by hand if it is leaking. Do not use a wrench, as you could over-tighten the valve.

  2. 2

    Remove the old valve if it continues leaking. Use the wrench to remove the valve from the water tank.

  3. 3

    Screw the new valve into the water tank with your hand. Use the wrench to tighten the valve two turns pass hand-tight. Do not tighten it anymore unless it is leaking, as you can damage the valve.

  4. 4

    Check the vent tube. If your water heater is powered by gas, check the vent for any obstructions. The vent is located on the top of the water heater and is made of sheet metal tubing. Use your hand to pull out anything that is blocking the vent.

  5. 5

    Inspect the water pipes for leaks that connect to your water heater. If your pipes are leaking, tighten the fitting with the wrench. If tightening the fitting does not work you must replace the fitting.

  6. 6

    Remove the leaking fitting with the wrench.

  7. 7

    Place the new fitting and screw it on tight with your hand. Secure the fitting in place with the wrench.

  8. 8

    Inspect the water tank walls. If the water tank walls are leaking, then you must have a professional replace the tank.

Tips and warnings

  • If the leak is coming from the tank itself and not the valve or pipes, you will have to have the tank replaced. A leaking water tank is dangerous and can explode. Contact a plumber to install a new one.

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