Why is my boiler leaking water from underneath?

A leaking boiler is no minor issue. If your boiler is leaking water, it could mean that the boiler is in need of an urgent repair by a gas engineer / plumber. Not only can a leaking boiler water damage, but it can also lead to electrical faults and costly repairs potentially requiring replacements.

Once you spot a leak you should turn off the water supply and your heating, wipe off any water from the area and contact a Gas Safe Registered (GSR) engineer to inspect your system. Do not try to fix the issue yourself as handling boilers is dangerous and should only be done by qualified professionals.

Should you find your boiler leaking water, here’s what could be causing it:

• Small leaks of water could mean you need to top up your boiler pressure.
• The pressure relief valve could be releasing extra pressure from the system.
• The heat exchanger could be damaged.
• If you have a new boiler, the joints where the heating system pipes meet the boiler may have been badly sealed.
• If your boiler is getting old, some parts could have stopped working.

All of these faults are typically repairable. But in some instances, you may need a new boiler.

Warranty

Before you call an engineer out to fix your leaking boiler, check your guarantee or warranty to see if you’re still covered by the manufacturer. Depending on where the leak is coming from they may send an engineer to fix it at no additional cost to you.

Usually, the leak would need to be coming from the boiler itself for the manufacturer’s warranty to cover it. If the leak is coming from pipework then it’s less doubtful it will be covered.

Leak error codes
Worcester Bosch boiler error codes for water leak:
A1, E9, CE207, HO7

Ideal boiler error codes for water leak:
F1, L1, FD

Vaillant boiler error codes for water leak:
F.22, F.24, F.13, F.73, S.41, S.53

Baxi boiler error codes for water leak
117, 118, 125, E78, H.02 – 06

Call a Professional

We’re always happy to talk to any of our customers about any issues they have with their heating, so feel free to get in touch for some expert advice!