Boiler Pressure dropping rapidly

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Hello All
I have a Ravenheat Silver star boiler and I know it is considered a poor boiler, I have had a lot of problems with pressure and airlocks within the system over the years, most winters in fact I have to go over the system but once working and in regular use it seems fine.
Now I have a problem where the boiler is losing pressure every hour or two and I see no visible leak although on the Flexi pipe filling loop the top handle spits a lot of water out every time i repressurise, could this be the issue, I can't see how as it only leaks when i'm adding pressure though it has gradually gone from dry to a drip to now too messy even with a cup under so regardless I'd appreciate help in replacing this (Will upload photos).
The other culprit could be the pressure release valve, we replaced that a few years ago and it was awkward, I believe we needed 3 wrenches and only had two as when we tightened two another part (of the pipe it sat on top of) would turn and so we took our time until we thought it was tight but I wasn't 100% happy but when we tested it worked fine and has done so until now, a similar loss of pressure was present before we replaced the valve so I guess I need to check this again?
I just figure replacing the flexi pipe is my first step, can i just replace the top part and reattach the pipe? It looks that way so I guess my only other questions are do any of you know what the part is and is that (top one is faulty) the hot or cold end, i'm guessing its hot which means I need to drain the system right?
One more thought is that the pressure started dropping much more when I ramped up the central heating temp, I generally have it on half or so but sometimes putting it up helps to get the system moving again and I do have a few rads not completely hot since I had one moved a few months back, could the extra temp have started a leak somewhere? They do get very hot when on full which is why we keep it lower.
Any thoughts or advice welcome though please, as I said I know the boiler is poor :(
Thanks for the help its much appreciated!
(Photos attached)
 

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There should be a pipe going to the outside, is this dripping ? Also, when your heating is on does the pressure rise into the red section on your gauge ? And thirdly, do you never go to bed ?
 
What makes you think the pressure loss is due to the boiler?
My first thought is that you are losing water from a leak elsewhere on the heating circuit!

I would pressurise the system, isolate it from the boiler by closing the flow & return valves. Leave a while and see if the gauge drops (which I doubt as you'd see water at the boiler). After an hour or two, open the valves back up and watch the gauge as you do... If it drops immediately then the leak is somewhere on the rad circuit. Do you have suspended floor downstairs? If so, you could have a leak under there which will not show up as damp on the decor like it would if leak was in upstairs circuit.
You might have a pierce in a pipe where it crosses a door threshold or a leak if system was converted from gravity to sealed!
Try a bottle or two of leak sealer in the system else you'll have to track it down and repair!
 
If there are no visible signs of a leak anywhere apart from the filling loop as you turn it (this is common) and the pressure relief valve is discharging you will more than likely find you have a flat or burst expansion vessel in the boiler. This means that as the heating water gets hotter it expands more and if the expansion vessel is faulty the pressure will just build up and the pressure relief valve will just dump the water outside as a safety feature.
 
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Solved! (2 posts down)
Hi Gigz,
1- there was a pipe until somebody stole it! now its just a hole in the wall but the snapped pipe edge is there so if anything you'd see a leak more clearly against the wall, it was a bit mucky but there appeared to only be a bit of condensation there so I guess it depends how much water your talking? the heating has been on a couple of hours, i'll post a couple of pics to see what you think.
2 - The pressure doesn't seem to rise when the heating is on though I remember there was a phase where i'd repressurise to around 2 1.5 to 2 bar and it would go up to 4 (max reading) I used to wonder why there was a delay in the pressure reading but I haven't seen this for a while?
3 - I had been up with the baby which is kind of why I need to get this problem resolved, it's working with the constant repressurising atm but i can't afford for it to stop coming into winter!
 

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Solved!(Next post)
Hi Dilalio,
No all floors are concrete and I have traced the visible pipes around and there are no signs of a leak, also there are no signs in the ceilings.
Although they sound simple enough, I'm a bit clueless when with your other suggestions as i've never done a lot with the system myself.
Are the flow and return the two hanles directly under the boiler, theres a red and a blue i believe, I have never done this before but it sounds like a solid way to determine if there is a leak out of the way somewhere< I understand the heating must be off so as to not cause damage right?
Also another basic question, where is the leak sealer usually put into the system?
Thanks
 
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Found the leak, it's on the old rad in the utility room, the bottom corner has rusted and theres definitely some wet there so gonna get onto a mate now to see if he can replace that for me
Thanks all
 
Yeah, I should have seen that sooner but I was convinced it was on the boiler due to previous pressure problems, guess I learnt a lesson here though as I knew that rad was on it's way out.
Thank you guys anyway!
 
You've just learned the first rule of faulfinding/repair - rule out the obvious first ;). I've been in this game for 30 yrs and i've still not sussed the second rule yet.
 

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