Why Does My Boiler Keep Losing Pressure?

This has got to be one of the best, most informative, well explained, no nonsense videos I’ve ever watched on YouTube. We’re losing pressure somewhere and this has helped me understand much more than I already did with what could possibly be causing it. Well done sir!

Don't be shy/modest about the presentation - it takes loads of skill to present 36 minutes of video with smooth and clear speech and not have to edit it loads - nicely done. Thanks for lots of good info. Sadly it's true what people say in the comments - a lot of people don't know their job anymore and to be able to work out the problem oneself saves loads of time, money and hassle and it make it easier to identify a trader who does know what they are doing. Nice one.

Hi Roger, your video series is excellent. I’m nearly 60, I am so grateful that my Dad is a very practical guy and gave me a great education in my youth. This has empowered me so much in life, from maintaining my own cars, installing kitchens and bathrooms, to plumbing and electrical work. Sadly these are skills that subsequent generations seem to have missed out on, the number of times I have helped friends and family where so called professionals have been utterly useless amazes me.

I learnt so much from this that I have to say it was a very impressive presentation. One of the best I've seen without all the gadgets & video aids, and I used to deliver them professionally as a teacher, lecturer and commercial trainer!

Hi Roger, I like your idea of using perfume to find a water leak. About two years ago I had a tiny leak I couldn't find. Boiler pressure would go down just below the normal 1 bar in about a year. I used a stink bomb and injected it into the water system. No problem finding the leak with that terrible smell. Turned out to be a compression joint on a micro bore pipe to a radiator in my kitchen. Seems to me that a nasty smell is easier to find compared to a nice smell. Also a nasty smell gives you more incentive to find the leak quickly.

Roger, thanks very much for this video, diagnosis is a tricky thing and sharing your years of experience is of great value. I drained my system just over a year ago and after filling it up again the boiler kept tripping out, the pressure kept falling and flooding out of the pressure relief and I had to keep topping it up. I thought it was probably the expansion vessel but, not being a plumber, I wasn't sure. I contacted a few plumbers but none of them were interested in doing an investigation to find out what was wrong. I turned down the temperature on the boiler, which pretty much fixed the overheating, but I have been topping it up every week or so for the past year and a bit. Thanks to your suggestion of pressing the air valve to see if water came out, I was able to confirm that the diaphragm was gone and immediately ordered a replacement expansion tank. It's all fitted now and hopefully my days of weekly topping up are over. Once again, Thanks very much!!

Hello Roger. It's really refreshing to listen to someone who knows what they are talking about because they are speaking from experience. A great presentation full of useful and interesting advice. Thank you.

I know hardly anything about heating systems and plumbing ; but I found your presentation to be extremely informative, entertaining and easy to understand. Many thanks!

An EXCELLENT practical clearly explained presentation. A presentation like this takes real skill and expertise!

I had no clue about all of this, but you've done a great job of explaining all of this!

I had my system changed from an open vented to a sealed system about 5 years ago. Never fully understood how it all worked, but I do now. Thank you very much.

What an excellent public speaker this guy is. Direct and clear explanations with nothing superfluous. Very rare.

Robert. This material is so comprehensive that helped to understand the dependencies and have broader overview. Really I appreciate you sharing your experience. I have drop of the pressure from 1.8 to 1.1 bar every abot six monts. The instalation is about 3 years old. Boiler with external 200l water container for hot water. So I'm going to start with checking this air pressure compensation container.

FYI Our long term 'leak' was due to the expansion vessel gradually losing pressure. We were searching for a physical water leak around the property for months. Pumped it up and has been fine since.

Very comprehensive covering a lot of ground. I have a system which builds pressure but i am waiting for my annual Gas safe service to change the expansion vessel which has a wet schrader and the same clunk sound all round as the system pressure runs up from setting initially at 1.3 bar to level off at 2bar cold and runs at 2.6 so no major fluid losses so far . My boiler is 11 years in service now so my main fears will be upset valves after they have been resting for so long.

I learned more about how modern boilers work in this video than everything else I have learned over a lot of years! Always love your videos, but this one was outstanding! SO well explained!

in holland we normally have expension vessels outside the boiler and since the pressure of the cold water is higher then the boilerpressure youre last solution is the other way around with us. for looking at the condensing part of the heat exchanger: we often uses hoses to connect the condensing part so we fill the heater up high and let the hose hang in a cold way above a bucket.

Brilliant, well explained and easy to understand. Im a plumber with 7yrs experience but that was spot on. Exactly how they taught it at college

That was a lot more technical than expected. Not a DIY job! It’s great to see this level of non-hand-wavy detail on YouTube.

Thanks Roger a long video but worth every minute