turbomax VUW 242/1E / 282/1E how do i decrease the pressure as it is above the 3 bar?

[sezza]

hi I have not idea about boilers but my boiler has been increasing in pressure and has been over the 3 bar for a few days, my overflow pipe is leaking at the side of my house and i have no idea as to how to relieve this pressure. i have looked through the booklet but can not work out where the pressure relief valve is? it was suggested to me to try and empty some water out of the system using the radiators, i did this and the pressure went down to 0 but as soon as i turn it back on the pressure builds back up to just over the 3 bar. As i said im not great with this type of thing but am willing to try n sort the issue out myself if this is possible.if any one at all can help me out i would appreciate some advice. thanks sarah

[Phil L]

The filling loop is in the 'on' position, look in the manual for the filling loop and it will be this that is causing the boiler to repeatedly fill up

[Mike Humphrey]

Check that the filling loop is off - there should be a loop of hose with a tap on it to refill the system, usually next to the boiler. Make sure the tap is fully off, and disconnect the hose (one end will unscrew). A little water might come out of the hose, but if it keeps running then the tap is broken. The filling loop should really be disconnected whenever it's not being used, but most people don't bother.

Anything else is likely to be a bit more tricky to fix. If the pressure is lower when the boiler is cold but goes up rapidly when it heats up, then there's a fault with the expansion vessel - it may just need repressurising or may need replacing. If the pressure goes up slowly even with the boiler off, there's a leak somewhere from the mains to the heating circuit, most likely within the boiler.

Mike

[Skipweasel]

Probably looks rather like this...

this case, it's the two black taps, though obviously yours are likely different.

[geoff]

And don't forget to remove the filling loop once it is isolated, it's against your local bylaw to have it permanently connected

[Lee]

On our Vaillant 282/E the filling loop is internal...

[John Rumm]

The pressure release valve is usually inside the boiler and is connected to the dripping pipe you see outside. They are usually set to vent excess pressure when it exceeds something round 3 to 3.5 bar. There should be no need to alter it under normal circumstances.

For background on how the various bits of sealed systems work, read this:

try and empty some water out of the system using the radiators, i did

It sounds as if mains pressure water is somehow getting into the heating circuit. Normally this is sealed, and no water gets in or out. However there is a filling loop (the braided hose others have posted about) intended to allow the water to be filled in the first place. If the tap on this has failed and is letting water through, that would be one cause of the problem. I would suggest making sure the tap is off, and loosening one of the hose connections. No more than half a cup of water should come out. If it keeps coming, then you know what the fault is. (don't just unscrew the hose completely to start with in case you find the tap has failed full on!).

The other cause I can think of would be a hole in the heat exchanger that is used to produce hot water for the taps. This normally keeps the dirty stagnant water in the heating system separate from your tap water, however allows one to heat the other. If this gets a pinhole somewhere inside of it, then the mains cold water (which is probably at over 3 bar in pressure) can seep into the heating loop.