Main boiler pressure drops

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Hi All, My Main Boiler is dropping pressure on a daily basis, it’s fine whilst the heating is on...... then overnight the pressure drops below 1 & stops the boiler working. I go out top up pressure and it comes back on. Then I repeat this daily. I can’t find any leaks in the system.
 
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Imnot sure how to do that. Do I need a digital gauge???

Or can I use a foot pump?

Do I need to drain the whole system inc radiators?
 
Any water coming out of a copper pipe on the external wall where the flue is? Either constant drips or a burst of water when the heating gets up to temperature.
What does the pressure guage say when the heating is up to temperature?
 
Yes there is mate. Water coming out of the pipe outside........ I put a bag round to test & it’s now got few drops in.

The pressure when running is on around 2, someone’s just in the green sometimes slightly in the red???

Thanks again for you’re help
 
Your problem is your pressure relief valve is letting by, needs replacing. Also the pressure vessel charge should be checked when it's replaced.
 
Could I check the pressure myself? Would I have to drain down the whole system inc rads, or just isolate the flow pipes & drain boiler?
 
Could I check the pressure myself? Would I have to drain down the whole system inc rads, or just isolate the flow pipes & drain boiler?
Yes in theory - just isolate the boiler and release the water pressure. You're still going to need someone competent to replace the prv. If the pressure vessels inside the combustion chamber the answer is no to both though as you'd need to check the flue and gas rate etc before recommissioning
Ps disclaimer-- that doesn't include me
 
Could I check the pressure myself? Would I have to drain down the whole system inc rads, or just isolate the flow pipes & drain boiler?

Easily! If the system has a special valves.
 

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The PRV may not be faulty, and the problems could be down to the expansion vessel. The PRV should release water at 3bar, and if the pressure going too high due to a faulty expansion vessel, then the PRV could well be acting normally. The engineer should check both before replacing anything though.

The caveat here of course, is that you shouldn't be taking the cover off the boiler, and heaven forbid that I suggest you use youtube to learn how to check the pressure in the expansion vessel. With the number of times that you've refilled the system, you're inhibitor will now need topping up.
 

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