Boiler Pressure Relief Valve Leaking and What to Do

The pressure relief valve of your boiler is a very important part of your heating system. This is because it is a safety valve that protects your heating system from building up too much pressure. When that happens, you are faced with leaks or even the possibility of your heating system blowing up. When you notice a leak coming from your boiler pressure relief valve, attend to it immediately. Here are possible causes and solutions to fix such a problem.

1. The Relief Valve Is Defective.

Eventually, everything will give in to wear and tear. This safety valve should be checked at least every three months. If you haven’t checked it for quite some time, check it right away because unchecked valves can become rusted and closed.

IMPORTANT: Make sure to turn the power of the boiler off and allow the water to cool for about two hours. Then check the temperature first before you pull the lever.

2. The Fill Valve Is Defective.

This pressure reducing valve is designed to allow only 12psi into the boiler. If it is allowing the pressure to reach 30psi or higher, leaks can occur. To check if the fill valve is the problem, turn the boiler off, allow it to cool, drain some of the water until the pressure reaches 10psi. Don’t turn the boiler back on and wait if the gauge starts to go up again. If it does, then the fill valve may be defective.

IMPORTANT: If the fill valve reaches up to 30psi or higher and there are no leaks, shut off your boiler and call a plumber immediately because this is a very dangerous situation.

3. The Expansion Tank Is Water Logged.

This part allows water in the boiler to expand. Over time, it becomes logged with water or air starts to leak out of the tank, and when this happens the pressure relief valve will start to leak. Watch the pressure gauge when the boiler is heating, and if the pressure builds during the process, then the tank is most likely the problem and needs to be replaced.

4. The Aquastat Or Aquastat Relay Fails.

This gauge is required in most area codes, so if you don’t have one, you should have one installed. If your aquastat or its backup (the aquastat relay) is defective, the temperature of your boiler can reach a very high point. This is extremely dangerous and can cause your relief valve to blow off. You must immediately turn off your boiler and call a plumber right away.

5. The Hot Water Coil Has Developed a Pin In It.

Some boilers have a tankless water heater or what is also known as a hot water coil. Sometimes, this coil will develop a pin in it, and this causes pressure to seep into the boiler and leads to leaks in the pressure relief valve. Turn off the water to the coil and check if the pressure stops rising. If it rises with the water off, the hot water coil is the problem.

REMINDER: Because repairing a leak in the relief valve of a boiler involves handling water that can be extremely hot or boiler parts that are sensitive, there is always a risk of endangering yourself or damaging your heating system. So if you are not too experienced with handling such repairs, it is best to call a professional plumber.

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