My boiler is leaking water – What now?

04th July 2022

A regular, system or combi boiler leaking water is never a good sign but doesn’t necessarily indicate the demise of your appliance. Whilst there is the potential for substantial leaks to leave your boiler beyond economical repair, a lot of smaller leaks have simple and cheap fixes.

Here we’ll take a look at some of the most common boiler leaking problems to help you identify what’s wrong with your appliance. Remember, only Gas Safe registered engineers should carry out repair work on boilers and other gas appliances. Never attempt to DIY repairs, as you could endanger yourself and those living in your property.

Leaking pressure valve

One of the reasons why you might have a leaking boiler is if the pressure is too high. Your boiler’s pressure should be somewhere between 18 and 21 PSI or one bar. If the pressure exceeds this, you may find that the relief valve starts leaking water. It does this to stop your boiler rupturing.

Sometimes, limescale and other products inside your boiler can cause obstructions and increase the pressure. If this is the case, you’ll need to have them removed from the boiler, before having the pressure valves resealed.

This is one of the boiler problems you can fix yourself. To lower your boiler pressure:

• Make sure the filling loop tap on your boiler is closed
• Locate a radiator key and a small bucket
• Use the key to loosen the nut on the end of the radiator
• Catch the water in the bucket
• Tighten the nut

This process is called ‘bleeding’. You may need to repeat it on each radiator in your property.

Boiler leaking water from the temperature valve

If you’ve noticed that the temperature valve on your boiler is leaking water, it may be that the temperature of the appliance is too high. The temperature probe inside your boiler may be faulty and will need replacing by a gas engineer.

Water dripping from boiler pipes

If your gas boiler is relatively new and is leaking water around the pipe fittings, it could be a sign of an installation fault. Don’t panic, this doesn’t necessarily mean the gas engineer you hired has tried to pull the wool over your eyes. Small water leaks are quite common in new boiler installations and often hard to initially spot. Get in touch with them and they should return to check and fix the problem.

My boiler is leaking water from the bottom

Your boiler dripping water from the bottom isn’t good news. It could be a sign that the pipes inside your boiler have corroded. This is common in older boilers and is caused by oxygen in the water mixing with the metal to create oxides.

If the corrosion is isolated and has not spread across your boiler, you may be able to get away with just having part of it replaced. However, if the problem is more widespread, it’s likely more cost-efficient to scrap your appliance and buy a new boiler instead.

If there is dripping water coming from the bottom of your boiler, you’re going to need to get a Gas Safe registered engineer to look at it for you. They’ll be able to open up your boiler, assess the situation and advise you on the best course of action.

To stop the leak from causing water damage in your home, it’s a good idea to place a bowl or bucket underneath your boiler to catch the drips. If you can see where the leak is coming from, you could also tie a cloth or towel around the pipe to try and temporarily stop the dripping.

04th July 2022

Overflow pipe leaking

If you have a regular boiler and have noticed the overflow pipe outside your property is leaking, it’s likely there’s a problem with the float valve in your loft tank. The float valve looks like a plastic ball at the end of a metal arm in the tank. Its purpose is to control the water level of the tank. If it’s not doing this correctly, the water level will increase, causing the overflow pipe to leak.

To resolve the problem, you’ll need a new float valve and potentially new washers too. Unless you’ve done this sort of repair work before, it’s best to contact a heating engineer to do it for you. It’s a relatively straightforward job and shouldn’t take them very long.

Gas smell from boiler

Of course, it’s not just water that can leak from your boiler but gas too. This can be very dangerous.

If you can smell gas when your boiler is operating or there’s a musty smell, it could be a sign of either carbon monoxide or a gas leak. Switch off your gas supply, open up all of the doors and windows and leave your house. Phone the National Gas Emergency line on 0800 111 999 and stay outside. Make sure no one uses any electrical switches or naked flames near your property until it has been properly inspected and given the all-clear.

Some other signs of carbon monoxide include:

• Scorching or soot marks on your boiler
• Excessive amounts of condensation on your windows
• A yellow or orange pilot light on your boiler

Carbon monoxide can poison you and result in brain damage or even death. If you’ve noticed any of the signs above and are feeling unwell, seek medical attention immediately.

Is a leaking boiler an emergency?

Whether your leaking boiler is an emergency all boils down to what it’s leaking and the severity of the problem.

Gas leaks are always considered an emergency and should be treated as such.

Water dripping from boilers isn’t as much of an emergency, however, it does have the potential to render your appliance irreparable. Don’t ignore the problem. Get it looked at by a heating engineer ASAP. The quicker you act, the more likely you are to save your boiler (and your bank balance for that matter!)

Prevent boiler leaking water problems with regular servicing

The best way to prevent a leaking boiler from causing you problems is to have your appliance serviced annually. Through regular boiler inspections and maintenance, small niggles can be spotted and fixed before they become big, expensive problems. Annual boiler services will also check your appliance is working efficiently, ensuring you are paying the least amount for your gas.

Interested in low cost repairs by expert engineers?

We’ll fix your heating and then protect your home from any future breakdowns for the next 12 months. For more information, take a look at our repairs page here if you have any questions.