What to do if your Vaillant boiler loses pressure?

Simple test you can do to prove if its the boiler or the system. Top the pressure up to about 2 bar, Isolate the flow and return (Left and Right pipes) underneath the boiler You’ll need a 4mm allen key. Turn the demand for heating off. Go out for a while, long walk and a pint or two. In a few hours check the pressure if its dropped boiler issue.

What does it mean when your boiler is losing pressure?

It’s as simple as that. Unless the dial sits at 0 even when topped up (which could be a sign of a faulty pressure gauge), there’s a leak somewhere – even if you can’t see it. Whether you have an oil, system or combi boiler, pressure loss is usually directly related to a leak.

Is there a leak in a pressurised boiler?

So taking into consideration the above facts, what is your question? There is a leak somewhere.You have a pressurised system,the only way the pressure can drop is through a leak.Just because you cant see it doesnt mean it isnt there

Why does my Vailant boiler stop dripping when hot?

Very likely it’s the gland seal around the ‘tap’ that’s on it – the tap allows it to be closed if needed during servicing of your CH. It stops dripping when the system is hot probably because the fitting expands and seals orf the tiny leak, and possibly any further leak simply evaporates orf.

How does a faulty PRV cause a boiler to leak?

A faulty PRV will allow water to exit the system when it shouldn’t. In the event of high pressure, excess water is discharged through the PRV and out of the building via the PRV release pipe. This pipe can be identified outside.