/ News & Press / Video / BOILER KEEPS LOSING PRESSURE - WHY AND HOW TO FIX - Plumbing tips
BOILER KEEPS LOSING PRESSURE - WHY AND HOW TO FIX - Plumbing tips
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00:00:00.354 --> 00:00:01.187 - Hold tight. 00:00:01.187 --> 00:00:03.172 If you've been lucky enough to stumble across this video 00:00:03.172 --> 00:00:04.648 because you've got a problem with the pressure 00:00:04.648 --> 00:00:07.074 in your boiler and and the fact it's constantly dropping, 00:00:07.074 --> 00:00:10.167 then lucky you and any second now we're gonna get started. 00:00:10.167 --> 00:00:11.181 I'd just like to remind all of you 00:00:11.181 --> 00:00:13.737 that if this video helps you out, then please do subscribe. 00:00:13.737 --> 00:00:15.236 The links to the cards up here are present 00:00:15.236 --> 00:00:17.248 throughout the whole video and even at the end. 00:00:17.248 --> 00:00:19.073 So it'll be easy for you to subscribe 00:00:19.073 --> 00:00:21.037 and find any more information that you might need. 00:00:21.037 --> 00:00:23.946 We also share videos and photos of plumbing disasters 00:00:23.946 --> 00:00:25.786 that you guys send through to us 00:00:25.786 --> 00:00:27.655 at our Facebook and Twitter accounts. 00:00:27.655 --> 00:00:29.897 Anyway, I hope you enjoy the video and that it helps you out 00:00:29.897 --> 00:00:31.866 and remember everyone to hold tight. 00:00:31.866 --> 00:00:35.681 Plumberparts.co.uk, honest reviews and advice. 00:00:35.681 --> 00:00:37.960 So you've been noticing lately that the pressure gauge 00:00:37.960 --> 00:00:39.880 on the front of your boiler that looks very similar 00:00:39.880 --> 00:00:40.932 to some of the pressure gauges 00:00:40.932 --> 00:00:42.838 that I've got going on behind me at the moment 00:00:42.838 --> 00:00:44.020 has been dropping down. 00:00:44.020 --> 00:00:46.481 Now if it goes anywhere below kind of half a bar, 00:00:46.481 --> 00:00:47.888 then you know that you've got a problem 00:00:47.888 --> 00:00:50.443 and obviously if it's constantly going down all the time 00:00:50.443 --> 00:00:52.341 or that reckedly you're topping it up 00:00:52.341 --> 00:00:54.632 using a filling loop like the ones that we've got 00:00:54.632 --> 00:00:56.290 going on behind us at the moment, 00:00:56.290 --> 00:00:58.110 then you'll know that you've definitely got a problem. 00:00:58.110 --> 00:00:59.822 Now there's a few things that can cause this 00:00:59.822 --> 00:01:01.664 and we're just gonna go through them step by step 00:01:01.664 --> 00:01:03.146 and also give you a quick idea about 00:01:03.146 --> 00:01:04.843 how you can maybe fix the problem. 00:01:04.843 --> 00:01:06.904 I've seen a few other videos on YouTube about this 00:01:06.904 --> 00:01:09.125 and I don't really feel like they're covering very well. 00:01:09.125 --> 00:01:10.502 So we're gonna try and do that now for you 00:01:10.502 --> 00:01:11.667 and I hope you enjoy the video. 00:01:11.667 --> 00:01:12.500 So let's go. 00:01:12.500 --> 00:01:14.018 You may be aware that we've already done videos 00:01:14.018 --> 00:01:16.056 on how pressurized heating systems work 00:01:16.056 --> 00:01:18.627 and it's quite important to know the basics of how they work 00:01:18.627 --> 00:01:19.663 when it comes to finding out 00:01:19.663 --> 00:01:21.355 why you've got a problem with pressure drop. 00:01:21.355 --> 00:01:23.381 The main things to think about are that when cold water 00:01:23.381 --> 00:01:26.183 is heated up inside a boiler and inside a heating system, 00:01:26.183 --> 00:01:28.398 the cold water atoms and molecules start to move 00:01:28.398 --> 00:01:31.334 and get very, very excited and because of that, they expand. 00:01:31.334 --> 00:01:33.514 They usually on an unpressurized system, 00:01:33.514 --> 00:01:35.641 you have a tank in the loft with an expansion pipe 00:01:35.641 --> 00:01:37.677 that goes up there and that allows the water 00:01:37.677 --> 00:01:40.503 to expand up and down without there being a problem. 00:01:40.503 --> 00:01:41.713 On a pressurized system, 00:01:41.713 --> 00:01:43.589 instead of having the expansion pipe, 00:01:43.589 --> 00:01:45.668 you have what's called an expansion vessel. 00:01:45.668 --> 00:01:47.083 How they work is very simple. 00:01:47.083 --> 00:01:49.331 It's very difficult to compress water 00:01:49.331 --> 00:01:51.715 and so therefore you have an expansion vessel 00:01:51.715 --> 00:01:54.388 with a rubber diaphragm and on one side of the diaphragm 00:01:54.388 --> 00:01:56.982 you have compressed air that's usually compressed to one 00:01:56.982 --> 00:01:58.424 or one and a half bar 00:01:58.424 --> 00:02:00.920 and on the other side you have your heating system water. 00:02:00.920 --> 00:02:02.524 So as that water heats up and expands, 00:02:02.524 --> 00:02:03.575 it gets more and more happy, 00:02:03.575 --> 00:02:05.712 it can expand into the easily compressed air 00:02:05.712 --> 00:02:07.086 without letting air into the heating system 00:02:07.086 --> 00:02:08.755 because there's a rubber diaphragm in the way. 00:02:08.755 --> 00:02:10.752 So make sure that your heating system is nice and full 00:02:10.752 --> 00:02:13.403 of water at all times, you have a filling loop 00:02:13.403 --> 00:02:15.976 that fills up the cold water from the cold water main system 00:02:15.976 --> 00:02:17.751 and make sure that everything's okay. 00:02:17.751 --> 00:02:19.617 It's worth noting as well that the filling loop 00:02:19.617 --> 00:02:21.369 is not in all the time, okay. 00:02:21.369 --> 00:02:23.548 When you filled up the system, when you've done anything, 00:02:23.548 --> 00:02:25.616 you should turn off both the valves at each size 00:02:25.616 --> 00:02:27.640 and remove the filling loop braided hose 00:02:27.640 --> 00:02:29.059 and just hang that behind the pipe. 00:02:29.059 --> 00:02:30.516 The main reason we do that is because 00:02:30.516 --> 00:02:32.177 if you've got a problem with one of the valves, 00:02:32.177 --> 00:02:34.314 you could overpressurize the heating system and actually 00:02:34.314 --> 00:02:37.024 pressurize the whole heating system up to main's pressure. 00:02:37.024 --> 00:02:38.222 So now you've got a basic idea 00:02:38.222 --> 00:02:40.537 about how a pressurized heating system works. 00:02:40.537 --> 00:02:42.127 Let's look at problem number one 00:02:42.127 --> 00:02:43.694 that could cause a pressure drop. 00:02:43.694 --> 00:02:45.467 Firstly and most obviously of all, 00:02:45.467 --> 00:02:48.017 you could have a leak on your heating system somewhere. 00:02:48.017 --> 00:02:50.188 When it comes to finding leaks, the best thing to do 00:02:50.188 --> 00:02:52.152 is pop around all the radiator valves for a start 00:02:52.152 --> 00:02:54.031 and just make sure there's no leaks on them. 00:02:54.031 --> 00:02:55.758 Make sure you lift up the heads as well 00:02:55.758 --> 00:02:58.162 to make sure that there's no weep on top of the valves. 00:02:58.162 --> 00:02:59.460 Make sure that the compression fittings 00:02:59.460 --> 00:03:01.275 on each side of the radiator valves 00:03:01.275 --> 00:03:03.478 are nice and tight and there's no water anywhere. 00:03:03.478 --> 00:03:05.288 Just go around, run around with your hands 00:03:05.288 --> 00:03:07.670 and make sure that you've got no leaks there at all. 00:03:07.670 --> 00:03:09.218 That's number one on the list. 00:03:09.218 --> 00:03:10.683 Try and stop the leaks. 00:03:10.683 --> 00:03:12.900 If you find that you can't find any leaks anywhere, 00:03:12.900 --> 00:03:14.155 always look out for sort of 00:03:14.155 --> 00:03:16.108 dark brown patches on the ceiling. 00:03:16.108 --> 00:03:17.381 They can indicate leaks. 00:03:17.381 --> 00:03:19.529 After that, you're into the gnarly world 00:03:19.529 --> 00:03:22.527 of pulling up floorboards and having a look under the floor. 00:03:22.527 --> 00:03:24.451 Things like that can get pretty horrible. 00:03:24.451 --> 00:03:25.355 So that's number one. 00:03:25.355 --> 00:03:28.001 You might actually have a leak on your heating system. 00:03:28.001 --> 00:03:30.311 Number two, most modern combi boilers 00:03:30.311 --> 00:03:32.858 have what's called automatic air vents on them. 00:03:32.858 --> 00:03:35.427 Now they're great for when it comes to venting a system out. 00:03:35.427 --> 00:03:37.109 Everything gets vented automatically 00:03:37.109 --> 00:03:38.254 and it works brilliantly. 00:03:38.254 --> 00:03:40.614 But they can cause problems if the heating system 00:03:40.614 --> 00:03:42.820 hasn't got an adequate amount of inhibitor in it 00:03:42.820 --> 00:03:46.085 or if the pump setting is set too high for the speed. 00:03:46.085 --> 00:03:47.661 Let's go through both of those quickly now. 00:03:47.661 --> 00:03:49.689 What an inhibitor does is stops the water 00:03:49.689 --> 00:03:52.347 from reacting with the inside of the radiators 00:03:52.347 --> 00:03:53.459 and the inside of the components 00:03:53.459 --> 00:03:54.754 of the heating system itself. 00:03:54.754 --> 00:03:56.527 If that's not in there, you've got normal water 00:03:56.527 --> 00:03:59.179 going up against the insides of a radiator 00:03:59.179 --> 00:04:01.385 and causing horrible things to happen. 00:04:01.385 --> 00:04:03.653 Many, many months ago I started an experiment 00:04:03.653 --> 00:04:05.236 with two jars just like this, 00:04:05.236 --> 00:04:08.127 one with inhibitor in it and one with just water in it 00:04:08.127 --> 00:04:10.332 and then popped about 10 nails in each 00:04:10.332 --> 00:04:13.004 and I think you can see the difference. 00:04:13.004 --> 00:04:14.921 If I just pop these down so you can have a closer look 00:04:14.921 --> 00:04:17.566 at them, you can see the different state in the nails 00:04:17.566 --> 00:04:20.013 and if inhibitor is not inside your radiators, 00:04:20.013 --> 00:04:22.427 that's exactly what's gonna happen to the inside. 00:04:22.427 --> 00:04:23.965 Now, another byproduct of this 00:04:23.965 --> 00:04:26.082 is not just sludge and rust that goes around 00:04:26.082 --> 00:04:28.123 and stops a heating system from working properly, 00:04:28.123 --> 00:04:30.129 it's also hydrogen and other gases. 00:04:30.129 --> 00:04:32.405 What happens is the hydrogen can work its way around 00:04:32.405 --> 00:04:33.872 to an automatic air vent 00:04:33.872 --> 00:04:35.860 and the automatic air vent's just doing it's job, 00:04:35.860 --> 00:04:38.174 it's just sitting there having a nice chilled out day, 00:04:38.174 --> 00:04:39.677 a little bit of gas comes along 00:04:39.677 --> 00:04:42.661 and it lets it out quite happily, but what happens then 00:04:42.661 --> 00:04:45.084 is the pressure drops down on your boiler. 00:04:45.084 --> 00:04:46.756 So make sure that you've got a nice amount 00:04:46.756 --> 00:04:48.264 of inhibitor in your heating system. 00:04:48.264 --> 00:04:49.993 We've done a video about how to do that 00:04:49.993 --> 00:04:52.130 and that'll be appearing in the card right now. 00:04:52.130 --> 00:04:54.266 The next thing to worry about is the pump speed. 00:04:54.266 --> 00:04:55.389 Now the problem you have is 00:04:55.389 --> 00:04:57.926 if the pump speed is set too high and the water 00:04:57.926 --> 00:05:00.350 is not getting away from the pump quick enough, 00:05:00.350 --> 00:05:02.964 it can do a thing called cavitation, which is what happens 00:05:02.964 --> 00:05:05.324 where the pump impellers themselves split the water 00:05:05.324 --> 00:05:07.990 and air up and then you again create hydrogen. 00:05:07.990 --> 00:05:10.295 So turn your pump speed down, make sure you've got 00:05:10.295 --> 00:05:12.508 an adequate flow around the holder system 00:05:12.508 --> 00:05:13.994 and that should stop that from happening. 00:05:13.994 --> 00:05:16.022 Now obviously the hydrogen has to escape somewhere 00:05:16.022 --> 00:05:18.291 and guess what, it goes up to that naughty little automatic 00:05:18.291 --> 00:05:20.981 air vent again and drops the pressure in the system. 00:05:20.981 --> 00:05:22.172 So there are the other things you'd look at 00:05:22.172 --> 00:05:23.896 with a pressure drop 00:05:23.896 --> 00:05:25.272 on your pressurized system. 00:05:25.272 --> 00:05:27.295 The last two things to look at and unfortunately 00:05:27.295 --> 00:05:29.969 the most common are problems with the expansion vessel 00:05:29.969 --> 00:05:32.443 and also problems with your pressure relief valve. 00:05:32.443 --> 00:05:34.322 Let's have a look at the expansion vessel first. 00:05:34.322 --> 00:05:36.735 Like we described earlier on, the expansion vessel 00:05:36.735 --> 00:05:39.840 allows the hot water to have somewhere to expand to 00:05:39.840 --> 00:05:41.400 without pressurizing the heating system 00:05:41.400 --> 00:05:43.292 anywhere above what is a safe limit. 00:05:43.292 --> 00:05:45.868 Now, if the rubber diaphragm ruptures 00:05:45.868 --> 00:05:48.465 and let's face it, it is actually a moving part, 00:05:48.465 --> 00:05:50.070 then water will go into that, 00:05:50.070 --> 00:05:51.595 the air will get into the heating system 00:05:51.595 --> 00:05:53.763 and get taken out of the automatic air vent 00:05:53.763 --> 00:05:55.438 and basically what you'll end up with 00:05:55.438 --> 00:05:57.433 is an area of no expansion. 00:05:57.433 --> 00:05:58.673 Now, you'll probably think 00:05:58.673 --> 00:06:00.669 that's gonna make the system pressure go up. 00:06:00.669 --> 00:06:02.840 That is kind of true, but only for a little while. 00:06:02.840 --> 00:06:05.427 What'll happen is is the system pressure will go up and up 00:06:05.427 --> 00:06:08.901 and up and actually force the pressure relief valve to open. 00:06:08.901 --> 00:06:10.409 The way to know that 00:06:10.409 --> 00:06:12.729 with your expansion vessel is to find what looks like 00:06:12.729 --> 00:06:15.475 a bike pump connector on the top of it or on the side, 00:06:15.475 --> 00:06:17.443 press that and unfortunately you're probably gonna release 00:06:17.443 --> 00:06:20.129 all the air out, but if water starts to come out, 00:06:20.129 --> 00:06:21.718 then that's a bad thing, okay, 00:06:21.718 --> 00:06:24.558 and you're gonna need to put a new expansion vessel on. 00:06:24.558 --> 00:06:25.914 If you don't find there's any water come out, 00:06:25.914 --> 00:06:27.494 it might've just lost its charge 00:06:27.494 --> 00:06:30.326 through that straighter valve and you can get a bicycle pump 00:06:30.326 --> 00:06:32.594 and repressurize it and then use a pressure gauge 00:06:32.594 --> 00:06:34.588 to make sure that it's pumped up to one 00:06:34.588 --> 00:06:35.879 or one and a half bar. 00:06:35.879 --> 00:06:38.848 Another thing I'd also say is a lot of combi boilers 00:06:38.848 --> 00:06:40.838 only have an expansion vessel that accounts 00:06:40.838 --> 00:06:42.687 for the expansion of the boiler itself 00:06:42.687 --> 00:06:44.951 and doesn't account for the expansion of the radiators. 00:06:44.951 --> 00:06:46.344 I always say it's a great idea 00:06:46.344 --> 00:06:48.536 if your plumber's in and he's putting a new boiler in, 00:06:48.536 --> 00:06:51.085 ask him to whacker a moat expansion vessel 00:06:51.085 --> 00:06:52.510 somewhere else on the heating system, 00:06:52.510 --> 00:06:54.019 usually in the airing cupboard 00:06:54.019 --> 00:06:55.719 and then you'll halve the risk of there being any problem 00:06:55.719 --> 00:06:58.150 or the pressure relief valve 00:06:58.150 --> 00:07:00.566 'cause you've got so much more expansion space. 00:07:00.566 --> 00:07:02.420 Pressure relief valves are very simple. 00:07:02.420 --> 00:07:04.107 All they are is a rubber valve 00:07:04.107 --> 00:07:06.923 with a certain set spring on the back of the valve. 00:07:06.923 --> 00:07:09.171 When the water gets up to a certain pressure, 00:07:09.171 --> 00:07:11.033 the pressure pushes on that spring 00:07:11.033 --> 00:07:14.165 and then dumps the water at a safe location outside. 00:07:14.165 --> 00:07:16.622 They usually run with a little 15 mil copper pipe 00:07:16.622 --> 00:07:18.723 that sticks out the back wall of the boiler 00:07:18.723 --> 00:07:20.780 and usually the outlet is behind a hedge or something 00:07:20.780 --> 00:07:22.687 so you can never see them running or dripping 00:07:22.687 --> 00:07:25.004 and let's face it, most homeowners aren't gonna be 00:07:25.004 --> 00:07:26.167 looking for that anyway. 00:07:26.167 --> 00:07:28.312 So if you've got a problem with the expansion vessel, 00:07:28.312 --> 00:07:30.199 the pressure is gonna go up so much 00:07:30.199 --> 00:07:32.670 and it's gonna start dumping out the pressure relief valve 00:07:32.670 --> 00:07:34.704 and then your pressure drop will happen that way. 00:07:34.704 --> 00:07:36.658 Now a problem you can specifically get with the pressure 00:07:36.658 --> 00:07:39.543 relief valve is again that it is a moving part. 00:07:39.543 --> 00:07:41.445 The fact that you've got a spring on the back of the valve 00:07:41.445 --> 00:07:42.812 will mean that it is a moving part 00:07:42.812 --> 00:07:44.734 and it'll get weaker and weaker over time 00:07:44.734 --> 00:07:47.235 and eventually 50% of pressure relief valves 00:07:47.235 --> 00:07:49.475 will fail after about 10 years 00:07:49.475 --> 00:07:51.487 and what happens is they'll start to slowly drip out 00:07:51.487 --> 00:07:53.408 and you'll slowly notice the effect 00:07:53.408 --> 00:07:55.173 if you've got a leak on the system, 00:07:55.173 --> 00:07:57.261 but of course the pressure relief valve's piped up 00:07:57.261 --> 00:08:00.016 to dump that little drip outside where you're not looking. 00:08:00.016 --> 00:08:02.282 So a good idea is to just pop outside, 00:08:02.282 --> 00:08:04.096 find that little 15 mil pipe 00:08:04.096 --> 00:08:06.746 and just run your finger under that and see if that's where. 00:08:06.746 --> 00:08:08.528 If it is, then you've probably got a problem 00:08:08.528 --> 00:08:09.763 with the pressure relief valve 00:08:09.763 --> 00:08:11.735 and you'll need to get a plumber out to replace it. 00:08:11.735 --> 00:08:12.568 So there we go. 00:08:12.568 --> 00:08:13.704 I hope this video's given you a better idea 00:08:13.704 --> 00:08:15.197 about the problems you can have 00:08:15.197 --> 00:08:16.955 when it comes to your pressurized heating system 00:08:16.955 --> 00:08:18.753 and why you're getting a pressure drop. 00:08:18.753 --> 00:08:20.046 There are a few reasons. 00:08:20.046 --> 00:08:22.957 Let's face it, the most common are the expansion vessel, 00:08:22.957 --> 00:08:24.163 the pressure relief pipe, 00:08:24.163 --> 00:08:26.144 or obviously a leak on your system. 00:08:26.144 --> 00:08:27.716 One thing I would say, it's always a good idea 00:08:27.716 --> 00:08:29.417 just to top of the inhibitor in the heating system 00:08:29.417 --> 00:08:30.691 if you're not sure anyway 00:08:30.691 --> 00:08:32.863 and periodically ask your plumber to come out 00:08:32.863 --> 00:08:34.553 and just do a nice little health check on it, 00:08:34.553 --> 00:08:37.121 drain the whole heating system out, fill it all up again, 00:08:37.121 --> 00:08:38.950 pop a couple of tubs of inhibitor in there 00:08:38.950 --> 00:08:40.887 and your system should be nice and happy. 00:08:40.887 --> 00:08:42.803 Also at the same time, if you haven't got one, 00:08:42.803 --> 00:08:44.643 ask them to bang a magnetic filter 00:08:44.643 --> 00:08:45.961 on the return to the boiler 00:08:45.961 --> 00:08:48.198 and you're really halving any of the problems you might have 00:08:48.198 --> 00:08:50.144 just through the running of the heating system. 00:08:50.144 --> 00:08:51.631 If you need any more help or any more information, 00:08:51.631 --> 00:08:53.221 pop over to our website, 00:08:53.221 --> 00:08:55.208 Facebook, Twitter, give us a subscribe. 00:08:55.208 --> 00:08:56.957 Mr. G, my cat will be over there. 00:08:56.957 --> 00:08:58.332 He loves to be out that place. 00:08:58.332 --> 00:08:59.660 Anyway, I hope you've enjoyed this video. 00:08:59.660 --> 00:09:01.041 I do hope you subscribe 00:09:01.041 --> 00:09:03.186 and remember everyone, once you've got all that sorted out 00:09:03.186 --> 00:09:04.130 and you've figured out why you've got 00:09:04.130 --> 00:09:06.577 this pressure drop going on, to hold tight. 00:09:06.577 --> 00:09:08.374 See you later everyone, buh bye. 00:09:08.374 --> 00:09:12.207
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