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How do I know if my expansion vessel is faulty?


Expansion vessels should be able to work or operate for years without any intervention except for periodic draining and recharging as the unit gets older over time. However, hard water can damage the diaphragm inside the expansion vessel. In turn, it would cause it to fail by causing the diaphragm to pinhole. In this instance, you would need a replacement expansion vessel. However, the engineer will need to check this when they come to your property to see the boiler. The engineer will be able to decide on the best course of action, moving forward, for yourself. This blog will shed light on the question, how do I know if my expansion vessel is faulty?

When handling this type of equipment, first and foremost, you must remember that a Gas Safe registered engineer should take it. You must never attempt to meddle with the boiler cover or fix anything unless you’re a boiler engineer yourself. Now, when it comes to the testing part, a method should be set in place to do this. If you have a manual, you can also refer to it. Alternatively, with regards to the services we offer, look up our power flushing service in London and learn more about its importance.

Boiler Servicing and Maintenance

We believe that your safety and the safety of your home is of utmost importance during a boiler service or any other gas appliance-related work. Our customer-first approach is what has allowed us to build up a stellar reputation over the last decade. The only way to ensure that your boiler or appliance is functioning efficiently and safely is with regular maintenance and professional servicing, which are usually carried out annually. There are a number of reasons to get a yearly service.


How do you test an expansion vessel?

Usually, one would begin by first isolating any electrics surrounding the vessel. At the same time, turn off the flow and the return isolators. This would ensure less damage to your property by any water that may drain out of the system. This process usually occurs in five steps – inspecting, disconnecting, testing, charging and reconnecting. So, let’s move on and see how the following steps will help us if we ask ourselves how I know if my expansion vessel is faulty.

Firstly you would start with a visual check of the vessel to see if there is any exterior damage to the vessel. Secondly, press down the Schrader valve with a screwdriver to see if the rubber diaphragm is working or if any water sprays out. If water does come out, then it means that the diaphragm is not working, and you will need to replace the vessel.

Further Steps

Assuming that everything is alright with the vessel and when it comes to the disconnecting part, you will need to isolate and depressurize the cylinder. Then, disconnect the expansion vessel from the system. This will help avoid a false pressure reading. Thirdly, take a pressure gauge and test the air pressure with it. If it is under pressure, then recharge the vessel. A domestic vessel should show 3 bars and a 1.5 bar if it’s a heating vessel.

Next, you will need to recharge the vessel by using a pressure vessel hand pump on the schrader valve and inflating the rubber diaphragm inside the vessel. However, remember that these steps are best carried out by a professional who knows what they’re doing. Finally, reconnect the vessel to the system, repressurize and checked for leaks.

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What if my expansion tank is leaking?

There are a number of reasons for an expansion tank leak to occur. Usually, the older the tank gets and the more it deteriorates over time, chances are that various parts of the tank would begin to wear out as well, thus paving the way for leaks to take place. At the same time, if you spot a leak coming out of the tank and that too, from the topside, then you can try tightening it. This should control the leak. However, it is always wiser to get professional help if you’re not sure of how to navigate through this.

Also, remember to switch off any electrics and the heating before attempting any of this. We hope that this blog helped broaden your mind about the topic how do I know if my expansion vessel is faulty? Alongside this, why not check out our blogs or read specifically about topis such as how smart heating systems work.