Gas Training - Boiler Fault Finding - No Hot Water - Roy Fugler

gas training fault finding my name's allen hart and today i'm at viva training academy and we're going to go through some fault finding on a boiler where the boilers are not showing any fault codes so we've got roy um roy's going to go through testing and also changing the parts as well so hopefully this video will be off some use for you we are at viva now we are doing some fault-finding training our fault-finding courses so if you do want to know more if you want to do some fault finding then please get in touch come and come and see us and we're going to put on some special days while roy's going to roy's going to put some dares on um so yeah without further ado let's go over to roy [Music] thanks alan hi guys it's roy hugo at the viva train academy over in halifax and today we're gonna have a look at some fault finding scenarios and so we've got a main eco elite here the hydraulics are the same inside it so the water section the same as a baxi jewel tech and boxy platinum the potterton pro max so anything that we look at on the hydraulic side of it is the same the difference is the heat exchanger an aluminium heat exchanger we did a video um a while back stripping this boiler down and doing a service on it so some of you guys may have seen that video if you haven't have a look at it and you'll pick up some hints and tips so the scenario that we've got is the customers complaining that the hot water isn't as warm as it should be and so it could be a number of things and it's what we're going to do is try to find out going step by step how we would determine what the problem is rather than jumping straight in so the first thing we'd be asking the customer have you seen any error codes so we'll just drop the front down so this boiler's got a two digit display those of you are familiar with the range of boilers as i said the dual text the platinums the pro max's the main ecos you'll know that the digit display can on an error code it'll come up e and then whatever the error code is so at the moment we've got no error code the customer's saying that they've got no error code and so even before i turn the front off we've done all the electrical safety checks on there we're in the training academy so i know that when i turn the turn of power off and pop the fuse out i know the appliance is dead but out there in the field always do your safe isolation tv118 is really really important i know we keep talking about it on nearly every video but we don't want any any of you guys to get an electric shock off a boiler we're still getting a number of engineers that are getting killed every year through not doing electrical safety checks so safety is paramount with that in mind i've got my gloves on so the first thing i want to establish is does that boiler know when the hot tap is turned on because obviously if it doesn't register the hot taps turned on we're not going to get any hot water so before i've even took the front off i'm just going to turn the hot tap on and what we're looking for is to make sure that the little hot water light comes on when we get a demand so we can see that light come on so that tells us that the hall effect sensor inside there is activated on these it's a bobbin tab so that moves up and down so we can see that that's actually activated and that's working so it knows it's got a hot water demand however the little flame light hasn't come on even though we've got the temperature on the hot water turned up to maximum which in this case is 60 degrees it's not registered that we've got a hot water demand so that's the first thing we're going to be looking at why why hasn't it registered a hot water demand even though it's got a signal there it could be that it's going through its ignition cycles and things like that so it could be that with no gas so we need to be looking at things like that so i'm just going to turn the tap off now this particular boiler has got a preheat function and it's the only one in the range it's because of the aluminium heat exchanger so what we've got now is the little green light is flashing ah interesting the flame lights now come on so it's gone to pre-heat and the flame lights come on so it has actually lit so we have got gas there so we know we've got gas coming through and what it will normally do is it will light up and then modulate right onto its lovely setting because it's preheating the main heat exchanger it's because with aluminium it's very good at heat keeping heat in but transferring heat it takes a little bit longer to get up to temperature than the stainless steel heat exchangers that are in the the duotex and the pro-maxes and the platinums so that's why it's got the preheat so we know that it's actually got gas coming to it now it could be that the gas isn't um the right pressure so that's the next thing i'm going to be having a look at so i'm just going to whip the front off and then we'll come back and have a look at the gas pressure and check we've got sufficient incoming right so i've got the i've slapped the two screws i've lifted the front panel off and i'm going to attach the gas so the first thing i'm going to do is just turn off the isolation valve underneath and obviously we don't want to release any gas if we were in a customer's house they might be complaining that we can smell gas so i'm just going to slide off this other screw drop it down then i'm going to undo the test point so it's the bottom test point on this gas valve for checking the inlet pressure it's a zero type goodness so we go through a burner pressure we do an inlet working pressure and again if anybody's seen my videos will know that i'm battling about a four mil zero point eight screwdriver for undoing test points the reason being as a manufacturer's engineer in the past life i used to go out to lots of gas valves where it had been tubed up so that's the only screwdriver i'll use so i'm just going to slap on the test point you don't need to remove that test point just a couple of turns and then i'm just going to get the little adapter off the analyzer in manometer mode just connect that on there and then i can now close up that front because we're uh we've got the pressure on there just pop the screw in and just a quarter of a turn and then we're just going to pop the gas back on so we've got the gas on and as we can see i'll just pop my specs on so i can see now we've got a pressure of standing about 25 millibars we're in the training center so our pressure can be a little bit high so i'm just going to stick the hot tap off and and check what uh what temperature uh oh sorry what pressure i've got there so i'm just going to pop that on as we saw before it wasn't firing up so that's not really a good indicator so the best thing i can do is put it into chimney sweep mode and force it onto high fire just to make sure i've got sufficient gas so i'm just going to turn the tap back off so i'm going to turn both these controls all the way up to 12 o'clock now for you guys that are familiar with this setup the baxi duotex and the platinums and the pots and parallaxes you'll know how to put it into chimney sweep for those that aren't it's quarter turn twice so we go from 12 o'clock to 3 o'clock twice so once twice and back and what it should do it should come up and say sf sf means it's in chimney sweep mud or fluid sweep mode what we then need to do is to actually turn the central heating all the way up to maximum so what we're doing is going from zero percent all the way up to a hundred percent so now that's running at a hundred percent we can actually see what our gas pressure is like now back say say that providing we're getting 18 millibar at that inlet this bottle should perform to spec normally we do a gas rate as well and just to make sure we are passing the correct amount of gas so what we've got now we've got 21 millibars so we know that that figure is correct we know we've got enough gas there so we know that that's operating um so what we've got to look at now is why isn't it sensing we've got a demand so i'm just going to take out the chimney sweep while we talk about this so quite a term to take it out there so if we looked at a sequence of operation so what the boiler is looking at it knows it's got a demand because we've had the green light on it knows that the tap's running because that green light's on there we know we can get gas we know we can get the maximum amount of gas but why in hot water mode isn't it working so the next stage i'd be looking at is perhaps trying the central heating mode i know it seems a bit strange we're in the middle of summer we're filming this video in august so you might be watching it in winter but in august you don't normally have the heating on so all i'm gonna do even though we've got an old electromechanical clock what we've done we've connected all the boilers up onto these eph combi pack 4 controls and they're very simple to use i love using these and we're going to do some more videos on these particularly the open them um side of it this boiler doesn't have open thermo so all i'm doing now i'm just going to put it onto manual so i'm just going to push the manual button and that little flame symbol has come on i've got the radiator symbol come on said it's coming on for heating so what i'm going to do is turn that back up to max and i'm just going to let it fire up and check what the what it is in heating and that's going to prove that 90 of the bits and pieces in the boiler so it can eliminate things like if it's working on heating we can eliminate things like the pump we can eliminate things like the um the gas valve and all that the fan so we're looking at now does the heating come on is the gas running yeah we've got 21 millibar so it won't be running at full rate because these tend to be a little bit lower on the heating output and than the hot water output so we know the heating's working but the hot water is not performing so it could be the diverter valve isn't like letting enough water through into the hot water side but before we look at that what tells it the temperature but we're looking at the hot water thermistor now these particular boilers you may not be aware they've got an engineer mode or an information mode so we can actually look at the temperature on that hot water thermistor just quite simply by going into the engineer or the information mode so that's what i'm going to do next what i'm going to do is look at what temperature that hot water thermistor is actually signaling now to give me a little bit of a benchmark i'm going to connect on one of the probes off the analyzer and i'm just going to connect that on the uh the nut at the back of the hot water outlet so just underneath on the nut on the back of the upper water outlet because the hot water for mystery is actually located just underneath that little cover there so it's just on just as the hot water's going out through the boiler so i've just connected that on there so i'm just going to pop that back up we can have a look what temperature that's picking up so that's actually picking up a temperature i'll just disconnect the other one so we're not getting a false reading so that's picking up the temperature of about 25 degrees 26 degrees so we stick the hot tap on now to put this into information though we turn both furnace steps down to 12 o'clock and we use the central heating monster it's very similar to put it into chimney sweep motor combustion analyzer move so i'm going to use that 4 10 twice so one two now what should happen is that should come up and it should say oh there we go we've got a lot it's actually saying it's at 76 degrees so it's telling me that thermistor is registered 76 degrees well the water going through the tap and registering up on there he's actually saying it's at 31 degrees so there's a heck of a discrepancy there so the next thing i'm going to do i'm going to check the resistance on that thermistor it's a 10 000 and 25 degree thermistor uh so i can look at a a chart i can look at that and see what temperature and well what resistance it should be about 32 degrees so i'm just going to turn this off and i'm going to get that set up so we need to remove the the gauge so first things first i'm just going to turn the gas back off because obviously we may release a little bit and i'll say sometimes customers they can smell a little bit of gas and they think it's the end of the world if it's an edgy gas leak so just remove the hose tighten that little test point up we're going to pop the gas back on and then some ldf just to uh just in there just to make sure we've got no leaks on it and that's fine there's no leak on there i'm just going to wipe off that residual ldf um if i was any closer to any electrics in there i will probably be using a little gas sniffer so the next stage is i want to test that thermistor right so for testing thermistors there's two ways i could do it one is remove the cover and go back onto the pcb the other is in my pocket i've got a little test piece as a manufacturer's engineer we change harnesses and if you ever change your harness think about how you can utilize it i've just got the little connection for a thermistor there now i do this what i tend to do i get the probes off my multimeter and i just pop them up inside the little chocolate block so i'm just going to screw them into the little chocolate block so not overly tight so i've now got a good connection on there so underneath this little cover that's the lead just lift the little tag up so i've slid that off now that allows me to slide that in onto there click and it's locked in place and i've got a good connection i'm not fiddling about because the problem is with some of these thermistors getting onto the pins on them can be awkward so i can now check the reading so over on the multimeter i've got 2.157 and there's a k neon sign so that's 2157 ohms which is a lot higher than i would expect and normally a ten thousand dollar thermistor we're going to be looking at the water temperature in here is probably only it's only 30 degrees that's because we're inside so it's nowhere near it's over so that's the mister's fault so what we're going to need to do now is we remove that thermistor and replace it so i'm going to get set up to do that and then we'll come back and show you how we do that right so we're all ready to set up i've got a little tub underneath i'm just going to turn the cold mains off coming in and then open the hot uh the hot tap so the hot tap start to drip now i've got a new thermistor here i've also got a new uh a new copper washer boxes changed over onto little copper washers a few years ago from the fiber washers anybody familiar with the older boxes they're all 105s and things like that eventually they would leak around about the hot water thermistor so it's just a little copper washer that's on there which is now the replacement so it's a 13mm spanner because the thermistors are 13 mil so it's dead easy on this particular boiler up underneath i can get on there and i just slap it off and as i start to open it up i'll notice that the water and i'm just going to unplug the um connection off the lower pressure cut off just to give me a bit more room to get me handed i've not got all the large hands so as i start to slapping that off the water is coming out of the tank i'm just going to let it run so we don't get too much water coming out so these are 10 000 ohm thermistors at 25 degrees and their ntc's negative temperature coefficient what that means is the temperature goes up the resistance goes down and that's how they operate and so once we've got that running through we'll warm it up just to get rid of the water hopefully we shouldn't get too much water coming out this one i've got the old fiber washer on so i'll just remove that fiber washer we've got rid of that popped into the tray so we've got the new thermistor we're just gonna tighten that up hand tight nip it up with the spanner it doesn't need to be overly tight now one thing with with these connections one of the things i always get asked is people struggle sometimes they break the connections on them now they have a little nib and that little nib goes to the top where the groove is so if you slide it on and then it locks in place so that doesn't come out i've been out to lots and lots of boilers where the thermistor it's had that little tag broke and because people have overly um lifted it and broke it off it just needs sliding up and then that'll slide out so that's just to move a little tip so on this particular one that's in now that little slide is at the bottom so if we make sure the little nib is up at the top that'll slide in it locks in place and it doesn't pull off so then the little cover can go over the top it's just a little dust cover of water cover and then making sure we put the the lower pressure cut off plug back on in the right place so we can pop that back on so that's plugged in and pop the water back on underneath a little bit on the top of this water while the water comes through we can then shut the water off and just make sure we've got no leaks on there which we haven't so the next stage is testing that thermistor out so what i'm going to do is i'm going to pop the front back up again so hopefully this front will be stopping up now for a while around up and down up and down it's just one of those things that you end up having to do and i'm going to turn the selector switch back on i'm going to turn the temperatures back up to maximum on them both and then i'm going to connect up the differential thermometer across so i can measure the hot and cold temperature because what i'm looking for is hopefully a temperature rise of 35 degrees from cold that way i know everything's working so the first thing i'm going to do turn the hot tap off so we can see we've got the demand the little green lights on we've now lit so that's a good sign the work lighting before we do appear to be on high rate we can hear it running at high rate so i'm now going to get the other temperature probe i've already got one connected up onto the hot so i'm going to connect the other probe onto the cone [Music] i'm going to look at the differential across right so we can look at the differential now we've got a differential of 33.3 the incoming cold temperature is measuring it at 22.5 which is quite warm obviously we're in a training center our water comes into the building probably 100 meters from where we are so it's not a true reflection of a cold water temperature but as we can see the outlet temperature 55.1 we've got it set to a maximum of 60 on the boiler so that's probably what's stopping us at fully achieving the 35 degree rise but we're about 32 degrees with an outlet temperature of 55 i don't think any customer is going to complain so we've actually found the problem we've diagnosed the faulty thermistor we've changed the thermistor and we cured that problem so hopefully some of those little hints and tips that i've given you today they'll be useful to you in the future it's all about doing it step by step taking baby steps not jumping in modern boilers are very good at giving you error codes now sometimes you'll turn up like in this one there was no error code what the problem was the thermistor is what we call drifted it's gone outside it's calibration [Music] it's not outside the range so the circuit board's taking the reading has been a good reading it was saying it was about 70 of degrees the problem is if the thermistors say it's 70 odd degrees it assumes the water's at 70 odd degrees so it's just not going to fire up for hot water when it goes on to preheat it's looking at the main heat exchanger temperature so that's why it was coming through so hopefully that's been useful to you if it has give us a like give us a thumbs up and any questions you've got please ask us we try to get back to them as soon as we can obviously we're reasonably busy and and until next time it's been roy field with the viva train academy um bye-bye thank you very much for that roy and as always thank you to viva training academy and as i said early on in the video or at the start of the video we are putting on some training courses now so if you do want to if you want some more hands-on fault-finding then then please get in touch if you want some if if you want some more of these type of videos then just put some comments below and let us know what type of videos you want and we'll try his best to accommodate wherever we can so yeah thanks very much thanks for watching i've just got a quick look at the engineer manual for you here so you can get these manuals from the manufacturers so this is a boxy manual and this just goes through just tells you about the boiler tells you about the wiring diagrams sequence of operation tells your fault codes sometimes when you go into these fault codes as well in engineer settings you can you can see things like temperature of components etcetera and you can see if if you've got a fault or not quite easily just from these without even using your tools you can sometimes see if you've got a fault or not we've got all for mr charts as well in this so it's really as i said always just get your manufacturer's instructions if you can

Channel: Allen Hart

Views: 64,070

Keywords: viva training academy, gas training, boiler repair training, gas boiler, combi boiler, gas training videos, gas engineer training, no hot water, gas training course, gas training centre, gas course, boiler repair, boiler fault finding, gas safe training, hot water, gas training tutorial, Roy Fugler

Id: etZ_TAzqVt0

Length: 23min 42sec (1422 seconds)

Published: Fri Aug 06 2021