BOILER KEEPS LOSING PRESSURE - WHY AND HOW TO FIX - Plumbing tips

Does the pressure in your Combi boiler or heating system boiler keep dropping? Here's how to fix it! We'll show you why it happens, and how to fix it. We'll show you how the filling loop works with mains pressure, we'll show you how the expansion vessel works and can fail, how the high pressure relief valve can release pressure and how a lack of inhibitor can cause air and a drop in pressure.

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00:00 Introduction
00:36 Is your boiler losing water pressure?
01:13 Where does the water pressure come from?
02:08 How does the boiler filling loop work?
02:39 Solution 1 Leaks on the heating system
03:28 Solution 2 Air in the heating system
04:52 Solution 3 High pump speed
05:25 Solution 4 Expansion vessel failed
07:00 Solution 5 Pressure relief valve failed

[plumberparts]

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[GIBLETTS]

I am actually a plumber who is 63, so our young friend is great for me to keep constantly updated, , plus he is a really nice guy, thanks for sharing your knowledge, I can see you are going a long way, ,

[kelvinedwards]

I have been a breakdown engineer for 40+ years and a friend has a flat in london and was being conned . instead of writing out all of the possible reasons for constantly topping up the system i pointed her to this video...very good... i might look at your other videos now...lol

[adamtannock]

Another tip for combi boiler pressure drops. After trying all the above, if you’re still getting a drop you can fit 2 isolation valves under the boiler on the flow and return. Isolate this for 2 days and check pressure after. If it drops then it’s the boiler, if it holds and then drops after you open valves then it’s the pipe work.

[sinbadcleo]

Thanks for that clear explanation. I 'stumbled on' this vid not quite a week after I'd called out a tech-specialist plumber (Warranty Ts&Cs ) who found 'zackly what you described - a deflated pressure expansion 'balloon' and a gushing px. release valve hidden low down behind some spare bricks. Less than 5 minutes to diagnose, 20 minutes to service in and and on his way. I really like it when a skilled pro works fast and right, like that.

[John-obdh]

You can keep these new fangled boilers.ours was fitted in 67 .ideal stnd 40/ 60 boiler.floor standing.serviced every year. All its ever had fitted is one new gas valve ( 20 years ago ) i thermo couple ( 15 years ago ) and 1 new pump. Big detached house, 10 rads .even on coldest days we don't need heating on high.It never let's us down .As the last fitter said on its service .They don't make them like this anymore .I have all the spares ( only 3 spares) .gas valve, thermo links, thermostat assembly.no fancy electrics.No messing around adjusting pressure. Fingers crossed it will keep going as its only been here 54 years.lol

[swabs]

I cannot understand why this video has so many dislikes, I have read numerous forum posts about pressure drops on boilers and none of them are as comprehensive as this video. This video fully explained to me the various reasons for pressure drop and the cut away expansion vessel was great. Loved the video . Thanks

[stardust]

Explains it so clearly even I can understand it ! I had a new Combi installed 3 months ago & I’ve had to top it every couple of weeks - CH Engineer said it would settle - it hasn’t . Ive now good a good idea of what the problem is as overflow pipe outside is constantly dripping & so rather than feeling the Engineer is speaking to me in a foreign language I can have a more informed conversation with him - & that’s why the 3m dislikes as the old school cast iron boilers with a life span of 20 /30 years with occasional repairs have been replaced by boilers with umpteen plastic components, built in obsolescence & the creation of a whole new £££m industry to teach & test Heating Engineers who then go on to charge £££ to install, service & repair the dam things. They might be more efficient but I reckon these additional costs more than outweigh any savings on my gas bill

[mr.dahliaking.]

My neighbor recommended me for her friend, because she had a problem of her gas boiler mysteriously loosing pressure. On Sunday I will go there and check, maybe I will be able to fix it. Gosh, I haven't had many chances to work on heating systems, except in my own house, witch has become now sorta like my own learning grounds. Well, if there is a simple leak on system, or if there is simply bad vessel of Relief vale, I might as well get lucky. I'm learning everyday. I'm surprised that a middle aged woman is confident in 19 yo self thought plumber wannabe, in fixing her boiler. This video is going to be my guide. thanks a lot James.

[SkillBuilder]

Why so many hates? A quarter of a million views means that a lot of plumbers have probably lost a lot of money, but the sad fact is that a lot of plumbers aren't great at fault finding. I have been out to jobs where they have had three or four plumbers in and none of them have noticed that the pump has been fitted the wrong way round or something equally simple.

[annewilliams]

I have spent all day trying to fix this, online, phoning plumbers, getting baffled. I thought a picture of the valves might help, so spent more time online - then - I happened on this. IT IS BRILLIANT, a simple demo was all I needed. Thankyou ( one cold shower was quite enough)

[jcrego]

I always find these videos extremely helpful. Was losing pressure, looked around and found o ring on magnetic filter was seeping. Opened filter cleaned it out (really horrible job) and replaced o ring with a new one. Pressure remains constant. Thank you very much!

[stevenmcfarlane]

Not a plumber just someone that has to frequently top up the filling loop. Two plumbers have attempted to fix / replace expansion vessel. Thank you for your thorough explanation.

[Tonka-oslt]

Best video on boiler problems out there. Well done and thanks. You have helped me understand my problem comprehensively and it cost me nothing. Thanks again!

[m.f.b]

Thank you for a thorough explanation. I’m having a pressure loss on my boiler and keep topping up twice a day so I can get hot water and heating. I had about 3 plumbers from BGas, I’m insured with them, coming over to my house and none of them did a thorough check. The first one, balanced the radiators and left. Water pressure still low, next engineer came over looked at the water pressure gauge and left (I had just refilled it). Third one recharged the expansion vessel and said boiler needs to be taken down to repair completely. At this point, after 5 weeks of engineers missing appointments and other engineers hardly looking at the boiler itself, the problem hasn’t been solved. I have taken notes from this video and next time I shall prompt the engineers to check on these points you mentioned before they leave an unsolved job. Thank you!

[Anthony-gqdk]

I wish all plumbers knew as much as you do and could articulate it and explain it so well. Super video, again.

[ColinWatters]

Once a Pressure Relief Valve has been forced open (perhaps by a faulty expansion vessel) they frequently start leaking or opening at a lower pressure. So if you have a faulty expansion vessel that causes the PRV to open consider replacing the PRV at the same time. Not always necessary but they aren't very expensive and might save you another drive to the plumbers merchant.

[derrickmartin]

Brilliant, as a heating engineer i did not learn any thing from this video
, but most of the plumbers I know would,

[fardellp]

Another point - the PRV can develope a leaking seat, as it is contact with acidic/particle/general muck from the primary boiler water. This can be especially prevalent where the PRV has actuated due to over-pressure. When the pressure has reduced and the valve closes again, bits of grit are left on the valve seat which can fail to seal properly leading to a permanent dribble.

[petersabatino]

Good man I'm a heating engineer of 30 years and you are a pleasure to listen too.