Why Is My COMBI Boiler Running When It Should Be OFF, Is It Normal Or Is It Faulty?

hello is your combination boiler coming on when you're expecting it to be off or maybe essential heating is coming on again when it should be off but in this video I'm going to go through all the reasons which I find combination Ballers will be coming on when you're expecting them to be off so this video is for combination boilers only if you have a heat only boiler where you have that large hot water tank then I made a separate video all about the reasons why I hate only boiler may be staying on when it should be off and of course you can find that video in the card above now or down in the description so I'm going to go through some operational reasons why your boiler may be staying running and those would just be a simple adjustment on your controls on your boiler then there's some fault reasons why your heating may be coming on and some fault conditions in your boiler which will bring your heating on and I'll go through those with you as well and if you want to go a little bit more in depth then there's some electrical wiring information as well after I've gone through all the reasons why your boiler may be staying on and it should be off I then Summit all that with some simple steps and checks which you can do do to find out where your bullet may be staying running I'll also give you a little bit more information about how your boiler operates so it'll give you better understanding of what may be going on before I get on with it let me just quickly mention one of my other videos 10 energy saving tips which you can do to make your system more efficient which is going to reduce your gas bill and you can find that link in the cards above there and of course down in the description so why is your combination boiler running when it should be turned off now here's a couple of quick reasons why a boiler may be running When You're Expecting it to be off the first of which is when you turn your central heating or your hot water off you'll hear your boiler continue to run for about a minute to five minutes afterwards now this is perfectly normal and it's just a boiler keeping the pump on for the central heating it's just going to keep the pump running so it pumps that last bit of heat out of the boiler and into your system just keeping it nice and efficient the hot water keeps the pump running just to circulate the last bit of heat around the boiler to reduce the chance of scale build up and stop any hot spots all perfectly normal another reason if your boiler is installed in an outhouse the garage in a loft anywhere where it gets really cold most modern boilers have a frost thermostat inside them and there's a possibility that the ball is getting really cold and the frost them as that inside the ball that is coming on and it's warming up the boiler and it's bringing on the central heating because the ball is getting really cold so if your Frost thermostat is kicking in there's not a lot you can do about that if you switch the boiler off you're running a danger that something's going to freeze in your boiler and then you may get hundreds of pounds worth of damage to it so don't turn it off and firstly I never recommend installing a boiler anywhere when it gets really cold for these types of reasons right now let's deal with the most common reason which I find a combination boiler would be running when it should be turned off now the first thing I'm going to ask is when you say your combination board is running do you mean that the bullet is running but nothing is turned on so all your Taps are turned off you haven't got your central heating turned on and it's not getting hot and yet every now and again you hear the boiler come on it runs for about five minutes and then turns off again if this is what's happening to your boiler then you can always be certain then it's going to be a setting on your boiler to keep it hot all the time now different manufacturers have different names for this setting so ideal call it preheats Valiant call it Comfort or warm start Worcester call it Eco glow them call it Eco but they all do the same thing now this setting is only to do with your hot water and the idea is that the boiler will keep itself hot around 50 or 60 degrees and then when you turn your hot tap on the boiler is preheated so it doesn't take very long for the hot water to come out of the tap and that is all the setting is for but this also means that your ball is going to be firing up during the day and during the night when you're not using the boiler keeping itself pre-warmed just waiting for you to turn the hot tap on now if you turn this setting off you will notice that it takes a little bit longer for your hot water to come out of the tap maybe around 15 or 30 seconds but now your ball is no longer firing up Jonah day and night when you're not using it saving you gas an additional wear on your boiler and it's worth knowing that if you're most likely to use your hot water when you've got your central heating on then this is just like having preheat already turned on because your boiler is already hot running your central heating see hot water will come through nice and quickly whenever your central heating is on now this setting could be useful if you're on a water meter or maybe if your boilers in an outhouse or in a garage or Loft but if it is in an outhouse or someone where it's very cold then it's going to be coming on even more keeping itself preheated using even more gas now every manufacturer has a different way of turning on and off this pre-heat setting if it's not obvious on the boiler display then you may need to check your instructions and even then sometimes it's not in the instructions and I've had to phone up manufacturers to find out how you turn the setting on and off if you're not sure how to turn that preheat setting on or off on your boiler then I have made some videos on different boilers on how you turn this setting on and off and you can find those in the description below Right Moving on then so is your central heating running so your radius is getting hot when they should be off now this could be down to several reasons so the first thing I'm going to check for is do you have a heat control telling the heating to come on so I checked the timer on the front of the boiler if you've got one of those make sure that says off I find the room thermostat and make sure that's turned down if you've got one if you've got a separate programmer or a wireless control of any description I check that that is definitely turned off now with any wireless controller you're also going to have a receiver unit and that's either going to be in the boiler or it's going to be a small unit next to the boiler so I then find that receiving it and check that it's definitely turned off because sometimes these receiver units they lose their connection with the programmer and then it may be saying off on the programmer but the recipient is actually still turned on selling your central heating to come on or it may have become faulty and it's still turned on so quite often there's a overwrite button or there's a switch on the front of these receiver units and I switched that switch or press that button to see if it turns a central heating on and off on the boiler if it's working correctly you would normally hear a click come from the relay box as it switches on and off now quite often there's a light on the front of the receiving it also and whenever the heating is on that little green light is turned on again you can't rely on that because sometimes the light is off but the unit is stuck and it will be actually turning the heating to come on now if I think that this receiver unit isn't working correctly and maybe it is fraughty I then look to disconnect it obviously that means you're going to need to start taking things apart and if you don't want to take things apart then I strongly recommend you call a gas registered engineer now depending what receiver unit you have like this Honeywell t3r it's very easy to just undo the screw and remove the receiver units a word of caution most of these receiving its run on 230 volts so these connections that will now be live and that voltage can kill you so only do this if you know exactly what you're doing now these receiver boxes are pretty much all the same you have a live neutral on Earth and then we have two switch wires so these two wires are just a simple switch when the heating is on they're linked together by the relay box and when the heating is off the link is broken so a simple test is just to remove one of the wires and that should turn your heating off before I go through some other reasons why a combination boiler may be staying running let me just quickly introduce myself my name is Mark Ballard and I've been a gas registered engineer for nearly 30 years the aim in my channel is to help you with your central 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 a 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 the donation in my toolbox fund 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 now if when I remove the receiving it the boiler central heating turns off and if when I put it back on the heating comes back on again then that pretty much indicates that there is something wrong with the receiving it if it should be off now if you find that you're receiving it is faulty then there's not a lot you can do about it it's just just a case of replacing it for a new one and of course if you want to know how to go about doing that I've made a detailed video all about how to install and operate the Honeywell t3r now if you're definitely sure that all your programmers and timers and room thermostats are all working correctly and they're definitely turned off and yet your central heating is still getting hot now if you've noticed that the heating only comes on when you put your hot water on then that is almost certainly going to be down to the diverter valve in your boiler this valve switches from hot water to Central Heating and if it becomes faulty and maybe sticking you're going to find your central heating coming on with the water and then all that can be done then is to replace that diverter valve another reason why your central heating may be coming on when you've got it turned off is to do with your preheat setting and if you have a faulty diverter valve what can happen then is if that preheat setting is turned on so the boiler is trying to keep itself pre-warmed for your hot water but your diverter valve is sticking then that water which should be heating up just your boiler is going to start going around your central heating and bringing that central heating on once again if that's the case and the diverter valve is sticking or in the wrong position then all you can do is to get a gas registered engineer to replace your diverter valve and one last thing I would be checking for is if you have additional controls now on this combination boiler here you'll see that it has a three port motorized valve and this valve is used to divert the water to heat up a hot tub I've also seen them used to heat conservatories and underfloor heating and if you do have additional controls you want to check those also to make sure that they are not keeping your boiler on I thought I'd just at this point which I found once but it's pretty unlikely that you're going to have this and that is that you have a hot tap running somewhere which would keep your boiler running now this wrong property I visited the boiler kept coming on saying the hot water was running obviously no hot Taps were turned on but it turned out they had a leak under the floor downstairs and it had that much water leaking out of it it was actually bringing the boiler on like I said that is pretty unlikely and I've only seen it once in 30 years and finally the wiring in your boiler now every manufacturer has their own way of wiring their boilers but thankfully combination Ballers are usually fairly straightforward you have a live neutral and an earth and then switch wires which are used control your room thermostat timer or programmer now these two wires are normally just a basic switch link them together and it brings your heating on break the link and it turns your heating off so a simple test is just to remove one of the switch wires which would turn the heating off boilers are getting a little bit more complicated now where you have this OT connection which stands for open firm or on this boiler it's the bus connection which is for more advanced controls which controls the boiler output the other thing we need to watch out for is whether our switch controls are running on low voltage or running on high voltage if you get these wires wrong then you could end up blowing your circuit board and a new circuit board is going to cost around 200 pounds or more so I would advise not to go messing about inside your boiler unless you are a qualified engineer and one other very important point is that a lot of modern boilers like the Valiant boiler to get to any of the electrics you need to remove the front cover of your boiler this then gives you access to the gas valve and burner and removing the front cover will affect how they operates so only qualified gas Engineers should be removing covers of boilers so summing up wire combination bullet may be running and when it should be off so if your boiler is somewhere where it's really cold in the garage open it off then your Frost protection on the boiler could be kicking in and bringing the boiler on when the temperature gets down to around about five degrees and if that's happening there's not a lot you can do about it now the most common reason I find for a combination ball to be running when it should be off is done at preheat setting now the way you can check if you have preheat turned on or off on your boiler it's just a look on the display on your boiler and see if you can see a preheat setting and just see if it says on or off now there's nothing on the front of the boiler to indicate where the preheat is turned on or off the way to check is just to don't use your boiler so don't use your hot water don't use your essential heating for about four hours and then come back to your boiler and see if it's still hot if it's still around about 50 degrees four hours later then you can pretty much guarantee that you have preheat turned on on your boiler so you may need to find your boiler instructions and find out how to turn that preheat setting on and off if you don't have any instructions then pretty much all instructions are online these days so just look at what your boiler is and then download the instructions from there so moving on to central heating if that's coming on the first thing you want to check is all of your controls make sure that everything is turned off I do come across it a lot these days where someone's made an error especially with these digital controls and then that's bringing the heating on so make sure that your central heating controls are definitely turned off and finally a little bit information about how your combination boiler works now you may not realize that when you use your hot water and your central heating only one thing operates at a time on a combination boiler so if you have them both on so you have the central heating on and you have your hot water on only your hot water will be working your central heating will then be off because the boiler can only do one thing at a time and I see the hot water or Central Heating and hot water will always take priority over your heating so if someone takes a really long shower for an hour your central heating is going to be off for that hour whilst they use the hot water another useful thing to know about combination boilers is if your hot water is working there's not much reason why your central heating shouldn't be working because pretty much exactly the same things have run when you use your hot water or your central heating the only difference is is there's a diverter valve inside the boiler which switches the heat from either heating up your hot water or it heats up your heating so if you're not getting any central heating then it's pretty much going to be down to the diverter valve is not operating properly and that's also the same if your central heating is working but your hot water is not working then again it's pretty much going to be down to the diverter valve not working properly after that it's then pretty much down to full diagnosis just working out why is central heating all your boiler is running when it should be off so I hope that's all giving a better understanding of what's going on inside your combination boiler so that's about it then so if you want to watch my 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 there's always my toolbox friend bye for now and I'll see you next time

Channel: Mark Ballard LTD

Views: 11,893

Keywords: boiler running when switched off, boiler keeps running when programmer is off, why does my boiler keep turning on and off, combi boiler constantly running, why does my boiler keep firing up when heating is off, why does my boiler keep clicking on and off, central heating stays on even when switched off, why is my boiler still running when thermostat is off, combi boiler keeps running when programmer is off, why does my worcester boiler keep firing up when heating is off

Id: Ay8ytRxt2I4

Length: 16min 40sec (1000 seconds)

Published: Thu Feb 02 2023