Mark Ballard LTD
How to Fix Boiler Overheating, All the Reasons Your Boiler is Over Heating Explained in Detail.
Is your boiler Overheating?? I will show you all the reasons why your boiler may be overheating.
Show you what is happening, what to look for and how to fix the overheating problem.
I’ll explain, What causes it to Overheat.
To Cover; Pumps, Radiator Valves, Thermostatic Radiator Valves, Smart Thermostatic Valves, Automatic Bypass Valves, Boiler Thermostats, Hot Water Plate Heat Exchanger and the Main Heat Exchanger in your boiler.
Also additional advice on long term System Protection.
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Chapters
0:00 Why is my boiler Overheating? Introduction.
1:50 What courses a boiler to Overheat?
3:26 Radiator Valves Coursing Overheating of your Boiler.
3:54 Thermostatic Radiator Valves Coursing boiler to Overheat.
4:47 Smart Thermostatic Radiator Valves Coursing boiler to Overheat.
5:12 Air in Central Heating system Coursing the boiler to Overheat.
7:13 Blockages in Pipe Work Coursing boiler to Overheat.
8:59 Central Heating Pump Coursing boiler to Overheat.
11:18 Setting Central Heating Pump Speed.
13:03 Motorised Valves Coursing boiler to Overheat.
15:03 Automatic Bypass Valves Coursing boiler to Overheat.
15:54 Valves Left Closed Coursing boiler to Overheat.
16:27 Boiler Thermistor Coursing boiler to Overheat.
16:57 Boiler Main Heat Exchanger Blockages and Overheating.
18:42 Adey Magna Clean Professional 2 System Protection.
19:55 Hot Water Plate to Plate Heat Exchanger Going Hot and Cold.
Links To Other Help Videos.
VIDEO: How and Why you should add “INHIBITOR” to your heating system. Including “System Cleaner” and other “Chemicals”..
VIDEO: 10 Money Saving Heating Tips. Simple Things You Can Do Which Will Improve Efficacy and Reduce Your GAS BILL.
VIDEO: How to Replace a Central Heating Pump. All you need to know. With out draining the system.
VIDEO: How to bung a loft tank.
VIDEO: Glowworm F5 Fault, Boiler Over Heating.
Video: How to Install Adey Magna Clean Professional 2.
VIDEO: Leak on Wiring.
Coming Soon.
VIDEO: Smart Heating Controls, Drayton Wiser.
VIDEO: How to Balance your Central Heating System, Reduce Your GAS BILL.
VIDEO: How to replace a leaking radiator valve. With out draining the system.
VIDEO: How to replace a Radiator with out draining the system.
VIDEO: How to Fix a Radiator NOT Getting HOT! Most common Reason.
VIDEO: How to Remove an Olive. 5 Different Ways.
Video: How to Operate Honeywell T3R Programmer.
VIDEO: Is your boiler continuously losing pressure. What’s the problem.
VIDEO: How to clean the Magna Clean Professional 1
VIDEO: How to clean Vaillant Filter/ Spirotech Filter. Vaillant Protection Kit.
VIDEO: How to clean Vaillant Filter Version 2. Vaillant Protection Kit.
VIDEO: How to remove a radiator for decorating.
VIDEO: How to refit a radiator after decorating..
VIDEO: How to clean the Magna Clean Professional 1
VIDEO: How to clean the Magna Clean Professional 2
VIDEO:, How to add Inhibitor to a Magna Clean Professional 2
Recommended Tools.
Move Videos and links on my web site.
VIDEO: Review “Monument 15mm Olive Cutting Tool”.
VIDEO: Nerrad FireJet Blow Torch NTFJ500, Reviewing All the Good Point of this Blow Torch. https://youtu.be/9lymjdPTtcA
LINK:Nerrad Fire Jet Blow Torch. Highly Recommended.
http://www.markballard-ltd.com/recommends/nerrad-tools-ntfj500-fire-jet-blow-torch-black/ (amazon).
VIDEO: Einhell Classic TC VC1930S Wet & Dry Vacuum Review, 30L 1500watt.
LINK: Water Vacuum. I use this vacuum daily. Highly Recommended. http://www.markballard-ltd.com/recommends/einhell-classic-tc-vc1930s-30l-wet-dry-vacuum-cleaner-230v/ (Amazon).
The Gas Safe Register. https://www.gassaferegister.co.uk
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hello is your boiler overheating so maybe you have to press a reset button to get it working again and what does it suddenly start bumping and banging and frightening the life out of you or maybe it’s just sizzling away sounding like it’s just beginning to boil so in this video I’m going to go through all the faults which I come across which will cause your boiler to overheat so you should then have a really good idea on what’s going on and then of course I’ll explain what needs to be done or you can try doing to stop your boiler from overheating so I’m going to talk to you about radiative Valves and thermostatic radiator valves and now smart thermostatic radio valves and how all those can cause your boiler to overheat they’re now going to go through air in your system blockages in your pipework central heating pumps and what you can ingest and do on those most Rose valves automatic bypass valves somewhere in the middle I would go through a couple of other folks which I sometimes find which will cause overheating and then I’m going to go on to the main heat exchanger this is the engine of your boiler and if your boiler is over 10 years old or you’ve got a really dirty system then it’s quite likely that this could be the problem of why your boiler is overheating and then finally I’m going to talk to you about plate heat exchangers now these are normally only in combination boilers so if you do have a combination boiler and you’re having trouble with the hot water temperature then make sure you stick around to the end of the video whenever you see this little Banner here come up it means I made a separate video all about whatever I’m talking about at that time and if you want to watch that video you can then click on the link which you’ll find in the description below along with lots of other links to other videos I have made I wanted to quickly let you know that I’ve made a video on 10 simple things that you can do to make your system more efficient which is going to reduce your gas bill and we’re all going for an energy crisis right now and anything that we can do to make our systems more efficient and reduce our gas bill has got to be a good thing right without further Ado let’s get on with while your bullet is overheating now just a quick overview of what causes your boiler to overheat so I’ve drawn a nice big boiler here we have our upstairs radiators and our downstairs radiators so it doesn’t matter whether we have Loft tanks or whether we’ve got a hot water cylinder somewhere else in the house always a combination boiler the principle is still the same so your whole central heating system is full of water so the flame comes on and it starts heating up your boiler and the water goes through the main heat exchangeable gets heated up it goes through the pump around the central heating system where then returns back to the boiler now what causes overheating is when the water goes through the heat exchanger too slowly or it stops altogether and then the water inside your heat exchanger it starts to get really hot it may start to boil causing that bumping and banging saying you’re here and then it may trip out with an overheat fault so the reason for overheating is you have poor flow or no flow at all of water through the main heat exchanger and our job is to work out what is causing the water to flow too slowly through the heat exchanger now here is a glow and boiler and it’s overheated and so it’s showing F5 in a display now there are two things which I will be asking when I go and look at a boiler that has an overheat fault the first question is has the boiler been getting noisier and noisier until finally it is now tripped out with the overheat fault or has the boiler been working absolutely fine and now suddenly it’s overheating if your ball is suddenly just started overheating then it’s more likely to be a controls fault like this pump here now I just show you a couple of simple reasons why a boiler may be overheating now we’re all trying to reduce our gas bills and a lot of homeowners are turning off radiators they’re not using now this is absolutely fine but if you turn off too many radiators and maybe you’ve only got one open then there just may not be enough flow through that one radiator so that may cause your boiler to overheat the simple way to test this is just to turn those radiators back on and see if it stops the boiler from overheating this is exactly the same for thermostatic radiator valves if you’ve been around your house and you’ve turned all those down at low or even to the off position you may not get enough flow around your system and through your boiler causing it to overheat now one other quick point about thermostatic radiator valves if you have them on every radiator there’s a possibility at some time all the thermostatic radiator valves will be shut so you will have no flow and the boiler May overheat if every radiator has a thermostatic radiator valve you should always have an automatic bypass a lot of combination bullets have those built in but if you have a heat only boiler where you have that hot water tank you should definitely have an auto bypass if you have thermostats on every radiator I’ll go into automatic bypasses in a bit more detail in a couple of minutes A lot of people now are starting to use a Smart thermostatic radiator valves so we can now turn off individual radiators from our smartphones now this is absolutely fine and a great energy saver hurts if you only turn on one radiator again there just may not be enough flow through the boiler and cause it to overheat so here on my app here I’ve got my three radiators all linked together another common reason why you’re boiling maybe overheating is if you have air in your system or maybe not enough pressure in your system now this is fairly easy to diagnose quite often you will hear whooshing sounds or gurgling sounds or noises coming through your radiators and that was the sound of air and water being washed around the system all around your boiler if you have a combination boiler or a system boiler you want to just check the pressure make sure it’s between one and one and a half bar and even if the pressure is correct on your boiler you might want to consider just increasing it slightly because sometimes the gauges can become stuck and they misread and sometimes the electronic sensors misread also so find your filling Loop and top up your boiler if it needs it now here’s a valiant boiler it’s trips out with a f23 and that’s because there is air in the system I’m not sure why the air is getting in but there is definitely air in it and if we go to the Magna clean here we can hear the trickling of the air as it’s going through the Magna clean and also up in the Airing cupboard I can hear lots of trickling as water is just trickling around the system as soon as I let the air off like this I’m doing it from the Magna clean and I also did it from the air vent up in the area cupboard the bullet was then looking absolutely fine again so the question is how is air getting in the system the most common place air is drawn into the system is Daniel open vent pipe and that’s normally down to blockages which I’ll go into in just a sec so the Bullet I was just talking about is a bit of a mystery how air is getting in because it doesn’t have an open vent pipe but if you do have Loft tanks you want to make sure that the tank has water in it and the float valve is moving up and down now this video clip I took from another one of my videos which is how to bung up your love tank so you can do some work on your system without draining it so that’s where you can see a bun in the feed pipe and a cap on the open vent pipe you should never normally have these parts bunged up when you’re operating your system normally now moving on to blockages on your pipework on a traditional system where you have Loft tanks it’s quite common for the pipe width of camper locks where the feed pipe and the open vent pipe come down from the small Loft tank to join the central heating system those pipes just there become regularly quite blocked up and you can see this bit of pipework here which have just cut out of this system because the boiler was overheating is completely blocked you can’t see a speck of light through it now I’ve just pushed my long drill through it just to show you that this is a piece of pipe and you should be able to see through it so obviously this pit here was completely blocked making the boiler overheat another bit of block pipe work now this is a valiant ecomax combination boiler and it has this bit of a rubber tube in it now you can see here again I’ve removed that because the boiler was overheating and you can see the tube is nearly completely blocked up with magnetite only leaving a tiny hole in the middle which meant there wasn’t enough flow through the heat exchanger making the boiler overheat shut down rubber tubes seem to like collecting magnetite so it’s a good place to check before I go on to pumps let me quickly introduce myself my name is Mark Ballard and I’ve been a gas registered engineer for nearly 30 years the Ami channel is to help you with your essential Heating and your plumbing if you find this video helpful at all then please give me that little bit of feedback by clicking on that thumbs up and that will also help others to find the video you can click on that subscribe if you liked the video click on the Bell if you want to receive a notification and of course share the video with your friends a big thank you to everyone who has thanked me by getting me a cup of coffee and leaving a donation in my toolbox phone it is really appreciated and it does really help me to make more videos which will hopefully help you oh and don’t forget to check out my website where I’ve categorized all my videos and I’ve left links to all the products and parts that I recommend moving on to central heating pumps pumps are one of the most common reasons why your boiler will start overheating now this pump here is full of little bits of magnetite this is the impeller which spins around and this pumps the water around your central heating system system now all those little veins should be completely clear but they’re all completely blocked up with little bits of magnetite and here’s what the pump looks like after I spent some time cleaning out all the little veins and that is now going to pump the water around so much better now here’s a pump which I took out of a combination boiler now the ball was getting really noisy so rumbly and rattly and that’s because the bearing inside the pump has worn out and the shaft of the motor has started wrapping around inside the pump and to finally it would just stick and no longer run so if you’ve got a very noisy pump on your central heating system and the boiler keeps overheating every now and again it could very easily just be the pump which is all of a sudden just jamming and not running anymore now the bump in this combination boiler has just about run out of life it will run for a little bit and then it just stops and then the boiler overheats now I’ll show you what this boiler does first of all it’s overheated so I need to press this button here to reset the boiler and now because the pump isn’t running it doesn’t take very long for the boiler to overheat and it starts to make it always bumping and banging and screeching sounds as it overheats and then it shuts down and the overheat thermostat will trip out again now to tell if your pump is running you can just hold it and see if you can feel it vibrating but if you can’t tell if it’s running we can undo this big screw on the end here now be careful if you do decide to remove the screw because you’re most likely going to get water running out of the pump here and it might start squirting out and it might even be really hot and really dirty so be careful if you decide to do that now I’m going to try resetting the boiler again and see if I can show you the pump actually spinning inside here now I’m just going to put my small screwdriver into the pump and try spinning the shaft I’m going to give it a flick in the direction of the arrows and there you go the pump has now started running and you can see this shaft is spinning round but it doesn’t take very long until the pump stops running again and a boiler overheats again so I replaced that pump head and now the ball is back up and running again now one last thing to note about pumps is you can change the speed at which they pump at now whilst there is some science behind what you should be setting your pump speed to quite often though it’s just a bit of guesswork and seeing how well your system runs if you’ve got a noisy boiler and it’s overheating you may find setting the pump to number three that may stop people from overheating it may even improve the whole temperature of your system because a lot of modern heat exchangers in boilers have quite a high resistance and as the boiler gets older that will probably increase so by setting the pump to a higher speed and pressure it may just take away that noisy boiler and stop it from overheating with some Modern pumps these days you can set them so they will change their speed automatically or change the pressure at which they pump at automatically now I have found in some instances these automatic modes can conflict with the boiler and give you problems so if you do want to use the automatic modes I would suggest that you call any experience the engineer to come and set these automatic modes up for you now the owner of this pump called me because her border was actually shutting down and what I found was this dial on the front here had accidentally been turned and like I said it conflicted with the boiler and a boiler kept shutting itself down and running at a really low temperature and one last thing if you do change your pump speed then you should also just check up in your Loft tank to make sure you haven’t got something called pump over where you find water starts coming out of the open vent pipe because you don’t want that happening because that’s going to give you more problems or it might already be happening due to poor flow around your system if you have a sealed system and you don’t have Loft tanks you don’t need to worry about this problem moving on to most phrase valves I find that three port files or mid position valves they very rarely cause any problem with overheating because if they do stop working they’re usually just stick in hot water or Central Heating mode meaning that one of those may not come on but with these types of valves either both or just one of the ports are always open so the flow of water is not restricted now if you have a zone valves or two Port valves they shouldn’t cause a problem but if they’re not wide incorrectly they can definitely cause a problem then the way they operate is that when you turn your heating on the zone valve will open up and when it’s fully opened the zone valve would then turn your boiler on now if someone’s incorrectly wired up they may have wired it up so when they put the heating on it also turns the boiler on and the zone valve opens up on its own now that’s fine until the zone valve stops working then when you put your heating on the zone valve is not going to open then the ball is going to fire up but because the zone valve is closed there’s going to be no flow and then that’s going to overheat your boiler for sure but that should only happen if it’s not wired in correctly now I must point out if you have a unvented hot water tank the zone valve will be wired in differently again for safety reasons you may even have two zone valves in line with each other the first valve would be to turn the hot water on and off and the second valve would be the safety valve to ensure the hot water tank is not heated if it’s up to temperature but that’s less common these days but again the boiler should not be firing up when the valve is closed now I was called to a job the other day where the boiler was firing up and both Zone Bars were closed but that was not because the Zone Bars were wired up incorrectly it’s because there was a leak and the leak was leaking onto one of the plugs which control the zone valve and that was bringing on the boiler and then the boiler overheated because there was no flow now if you have a traditional system which has a zone valves fitted on it you will also need an auto bypass now that may be in the boiler or you may have an external one like this now if that bypass becomes blocked or faulty then that will also cause your boiler to overheat when the zone valve suddenly closes the boiler may be running at full power the sudden stopping of water flowing through it will often cause it to instantly overheat and the idea of the bypass is to let that water continue to circulate until a boiler has cooled down a bit it can be tricky to tell if these are working correctly what method would be to feel the temperature of the pipes either side of the bypass one side may be hot but the other side should be cold when the zone valves close you should feel that cold side suddenly get hot as the auto bypass opens up now a less common thought which I sometimes find when homeowners have done a little bit of Home Maintenance and they’ve accidentally left a valve closed so maybe on a magnetic filter with a cleaner filter and then they’ve closed the Fab and not opened it again properly or on a couple occasions that people have gone to do a bit of maintenance on the hot water they’ve gone for Aaron cupboard isolated what they thought was the valve to isolated but they’ve actually isolated this file here which is to balance the hot water and of course leaving any valve clothes is going to cause your boiler to instantly overheat now all boilers have thermostats inside them and on Modern borders we have these small electronic thermistors and on this boiler there is a red thermistor on the flow pipe and a blue thermistor on the return pipe now there is the possibility that one of these could become faulty and give you an error code saying that your boiler is overheating having said that I find that pretty rare these days because these thermistors do seem to be Fairly reliable and I’d say over the last 20 years I’ve probably only changed one or two now let’s take a look at the main heat exchanger this is the engine of your boiler every boiler and manufacturer will use a different heat exchanger now this is a stainless steel heat exchanger and I prefer to install boilers which use a stainless steel heat exchange they have a much quicker response time so the hot water pre-heat setting does not need to be on saving you gas and wear on your boiler when you turn your central heating or your hot water on the boiler fires up so the gas will light up inside the main heat exchanger heating it up now over time these do steadily tend to get blocked up and the bullet will start to cut off that is literally like it sounds like a kettle beginning to boil and that’s exactly what’s happening the water inside the heat exchanger is actually starting to boil and this is because the water is going through the heat exchanger too slowly now here’s what this border sounds like when it starts to kettle foreign boiler and I’ve cut it in half so that we can take a look at what’s inside it and you can see that this one is made up of lots and lots of tubes which are kind of all just squashed together and because these tubes are quite small it’s very easy for magnetite to get caught and stuck inside them and you can see that this tube right here is completely blocked up with magnetite now you can put chemicals into the system to try cleaning out this magnetite but I’ve not always found that to be that successful and then I’m afraid is a case of replacing the main heat exchanger which can be really expensive because obviously it’s the main part of your boiler or the more expensive option again is to change the boiler completely having said all that there is one option you can try which might get your heat exchanger back up and running again or even clear any other blockages that you may have if you don’t have a magnetic filter fitted on your system I strongly recommend that you get one for fitted these are not just a gimmick they do a really fantastic job of collecting that magnetite and if you look back through the video you’ll see a lot of the problems are caused by magnetite in the system so magnetite is the enemy of your central heating system now in this video I’m fitting a brand new Magna clean professional 2 to this system and then I add some Sentinel inhibitor to protect the system from corrosion but you can just as easily add a cleaning chemical to the Magna clean that would then circulate through your central heating system and through your main heat exchanger and hopefully it will gradually unblock it now I have used this method in the past and I have had some really good results but then also sometimes this method hasn’t worked and I’ve either had to repost the main heat exchanger or replace the boiler completely but like I said you do really want to have a magnetic filter fitted on your system because it will help protect your boiler against that magnetite and finally the plate to Plate heat exchanger now this is only normally in combination boilers and it’s what makes your hot water hot now if your hot water is fluctuating in temperature so it’s going hot and cold then 95 of the time it’s going to be the plate to Plate heat exchanger these become scaled up or blocked up with magnetite and then what happens is you’ll turn the hot tab on the boiler fires up there’s not enough flow through the main heat exchanger so the main heat exchanger starts getting really hot it gets too hot the boiler shuts down your water goes cold and then when the main heater changer has cooled down a bit the ball will fire back up again and then it gets too hot again and so it shuts down and so you’ll get a continual cycle of your hot water going hot and cold because there’s poor flow through the main heated stranger now putting a cleaner through your system may help this but in general I just changed the plate to Plate heat exchanger for a new one so that’s about it then so if you want to watch one video on 10 ways to reduce your gas bill you can click on the video just here and of course you can click on subscribe you can click on the Bell give me a thumbs up share it with your friends and as always my toolbox friend bye for now and I’ll see you next time
#Fix #Boiler #Overheating #Reasons #Boiler #Heating #Explained #Detail
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Very well explained.
I always watch Ur videos
Nice one Mark always enjoy your videos very thorough.
Hi mark,
Great videos, I have just put a new type 22 radiator in my living room but it's only getting warm at the top, do I need to open the lock sheild more? Otherwise have you any suggestions?
Kind regards
Barrie Silman
Why not have a closed YouTube channel for gas engineers.
The word your looking for is "causing". Not "coursing".
another good vid mark, the magnetite that come out of the old rads flushing direct was shocking , as i replaced 4 then cleaned the magna clean and run the filling loop while all were connected and a hose on the drain off outside, took the magnaclean off again too add mc1 500ml bottle and the magnet still caught a load of it , shocking , boiler presser now dose not rise as before and the boiler temp is not going up and down, still two old rad on system (round tops) and they work fine agitating made a world of differnance at least the system has flow now
Why do so many engineers call vaillant boilers valliant boilers?!
Super helpful and clear – thank you so much
Wouldn't mind your thoughts on F.20 error code on glowworm micracom 24 combi boiler, hot water comes on and heating radiators, then goes off for periods of time. Done a reset every time, but chasing circles. Running gas on LPG.
Great video, you might want to add the following fault I had with a Drayton 5wire valve head. The micro switch was stuck so whether the valve was actuated open or shut it still asked for the boiler to run. Fix options: replace and solder fiddly micro switch or just get new actuator valve head assembly (which is what I did).
High hot water and heating as well
Could not stop heating
House is very hot
Very interesting Mark ,thanks for sharing.
Great video's 👍
it is a great video. Thanks
our boiler banged 1 time and 1 kink and no blue (35°c-65°c
Avoid anything with the word 'smart' in it.
I have bleed my radiators and now it’s stop making noises but thermostat gauge on boiler goes in the Red now and don’t know why
Thank-you for ure video
Of all the videos (I've watched at least 5 of them), yours is the best!!! Thank you!