GAS valve testing is very difficult this video could help.

gas valves this is possibly the hardest and the most difficult subject of fault finding and diagnosing whether these very complicated products actually work and they're tested but first of all can i just remind breakdown engineers gas safe engineers please wear your gas safe card with you keep it in the pocket so as the door opens you can sew to the customer i am guest safe approved and they can check it if you are that customer and somebody is going to be working on your boiler ask to see their gas safe card if they can't produce it close the door and find somebody else because it is a requirement and it's a badge of honor and safety and competence so if somebody turns up and hasn't got one of these and they say it's in the office i'm waiting for it fine okay come back when you've got it and then find someone who has got one of these there this is crucial and especially for this subject gas valves [Music] so when we arrive in into the house the first thing we're going to do is have a look at the gas meter because we have an awful lot of problems so make sure that the isolating valve is in the vertical position check that the earth actually is connected correctly and also a good idea is to spray leak detector fluid around the joints and don't forget your gas fluid analyzer has an adapter for sniffing leaks so use it there at the meter next take a photograph one landscape one portrait just so you can look back and say yes that's the proof and everything at the meter is perfect before we can begin and take the casing off we need to do our four part electrical test and with our touch free volt pen to make sure that the boiler is actually zero volts this is because electricity and water blow fuses but electricity and gas make explosions so we want to make sure that that boiler that we're going to work on is 101 1001 dead from electricity the first stage that we're going to do is to make sure that the spur is turned off the fuse is removed and we check it's three amps at the boiler as you can see it's turned on so i want to make sure that the spur in the off position is actually dead we're going to need some tools firstly our gas fluid analyzer because we will need to check that the emissions are correct but with that gas flow analyzer we also need some extra probes one is going to be the gas sniffer and two a manometer because we have to check the pressure and digitally so i don't like watergate it's focused in that hundred percent perfect and they're awkward so either the gas root analyzer has a manometer built in or as an accessory you need to buy or you have one of these digital ones but it has to have two terminals on the top not this one these have now been discontinued and banned so make sure that you can measure the actual exact gas pressure the first stage of this is make sure that the black lead common is secured to an earth terminal then we're going to move our multimeter to ac so we've got the spur turned off the fuse removed or unplugged so what we want to see are zeros throughout the terminals so let's start from the live terminal how many volts have we got coming down onto the live terminal none perfect neutral none excellent the common none and the return switch live none so therefore this boiler is definitely vault free one of the problems that we have with gas valves is the installer manual quite often there's information missing for example how many ohms on the gas valve between this terminal that terminal or the color of the wire or any sort of information on the wiring circuit or down in the fault finding flowcharts so they're not all the same i've looked at quite a few manuals for the production of this video and i was you know shocked but i know the answer quite often they're just not there and you have to phone technical and that's why i made the app with fault codes it has a phone number straight to technical where you can get the answer while you're in front of the boiler and the first thing that you need to do before you phone them up is to take a photograph of the identification plate the serial number the gc number which model of that boiler is because quite often gas valves will be replaced after two three four five years so the manufacturer needs to know the serial number so they can say ah right you've got a mark ii gas valve and that has different values and different way of testing it another thing is is practice well a lot of training centers including the factory ones don't spend too much time on testing gas valves but here on wednesday definitely because i know this is an awkward tricky job and trying to find out exactly what goes on is difficult so here we've got a dozen boilers plus some valves and i show you exactly how to measure them so you can walk into this particular make and be better prepared so the first thing that we need to do is just have a look at the serial number because we may have to quote that well you will have to quote that to technical at the factory so if we look at this then we can see here which model and serial number is so i'm going to have a go and see if i can guess what it actually means but if you can subscribe to our channel and leave us a like and answer me in the section below what the serial number means so i'm going to have a go so it's an ecotec pro 28 r2 so that means version two and then the serial number here starts with the two so that's uk version the one i think means that it's natural gas but if it doesn't can you leave me a comment somebody who actually knows the zero nine means 2009 so we know that anyway and then the last two numbers here 29 is the week number of that year so 29 weeks it's going to be summertime i would imagine so we have to look in the book on 2009 to know exactly but that information is crucial to technical to help you out because as we can see there's several versions which might have a different gas valve a different pump different sensors different pcb we need to make sure that they know what we're standing in front of and that's why you need to use the fault finding codes app because there you've got either a direct link into technical which will be seconds away or reception who will pass you over to technical i've seen many many engineers leave a message on forum said that i went there this morning and i got this and this and this what should it be and that's a complete waste of time because they've just left the house cold not working and then sometime in the evening they're looking for help well if you use the app as it should be used you could just phone them up while you're there and the technical department will say right change it or don't change it whatever and they'll give you help in seconds and that's the way it's done that's why breakdown engineers can do better jobs more intelligently so first of all let's move the multimeter into ohms and we're going to check the multimeter is fine in the batteries and we do that as we've shown before put an x press it 21 22 the meter is refreshed no battery symbols come up so it's fine i've looked in this particular manual and there's the gas valve with a blue and a red and they happen to come down here the blue and the red and the manual says it should be around 52 ohms so if we remove the multi plug i can show you a close-up of this one and you can see here that it's got two silver a brassy and two more silver so there's two coils and the brass one is normally earth but we don't use earth here we always use the earth where the yellow and greens meet so here is another gas valve and it's got four pits you can see here so as always we measure from the first pin to the last pin and that combined reading of the one or two coils is what the factory information needs to have so that's just another way so it's always first pin to last pin and each pin to earth should be ol open line but that's the golden rule of measuring gas valves each pin that you do so this one's got the five pins ignore the earth in the middle so if we go from the first pin to earth it's always going to be ol open line everything to earth is open line with electricity on boilers it's dead easy to use so to measure this coil and it's showing 52 ohms i go from the furthest one so i'm going to put the black one here and the red one up this end and just give the meter time to whizz round put a few volts down and here we are exactly 51 51.6 that's near enough this board is really old and it's been in service until just a few years ago so now if we put the multi-plug back into its place what i want to do is measure the leads because that could be a fault and that's the reason why it's not working so as always black goes first to common into the blue and the red goes into the live terminal and again we wait and see and there's our confirmation 51.6 ohms that means that the pcb the leads and the gas valve are all on the same wavelength the next stage is going to be voltage so we need to find out how many volts ac or dc is going into that gas valve and that information you get from the installation manual or when you talk to technical on top of most gas valves you can see here where we've got our coil and it's known as a moji rig modulating regulator basically that's our dimmer switch to get the flames going up and down in the most economical way and quite often we don't know what they are so why are they colored if somebody can leave a comment down below who actually knows is it red ones are made in this country green ones are made in another country blue ones in another or something completely different i really like to know so if somebody can help us out that would be terrific so the moji rig as i said is a dimmer switch quite often if you remove one wire from the terminal here the gas flame burner will go down to low and then we adjust it with the screw on the top so we can only do that once we've read the installation manual and we've talked to technical because you could do serious damage if you do this incorrectly so this is crucial crucial crucial we understand that when we turn the top or the nut underneath or the screw on the top whatever that we know what settings we are making so therefore when we put the two leads together in it'll go into high flame and there again we can adjust it so it's not over gas and we need to check that with our app which is gas rate but that's on top of these things so if all we're really looking for here the quickest way is to get a steady reading that's almost certain to mean it's a good coil the same as everything else and here we've got a back one here live neutral and earth and again we don't need to worry about the earth so much but the two pins which is a plug that will make the gas go to maximum and then the dimmer switch on the top the moji rig then makes it go higher and lower depending on the information it receives from the heating flow sensor or stat and the return heating sensor or stat but that's where it gets this information to stop the boiler overheating and obviously the other way around is to under heat so that this is an incredible test and make sure that you understand a steady reading is almost certainly going to tell you that coil or this solenoid operator which is basically maximum on off is actually working correctly but as i say a million times which is why people run away from gasoline quite rightly is phone the factory get that information and use that when you're going to a boiler to check whether the gas valve is actually working or it should be replaced by the latest version you may come across a gas valve which has got two parts to it so you've got a solenoid here and a solenoid there this has got purple and blue but sometimes both of these are the same color it could be yellow yellow who knows what colors and you need to make sure that the correct one is in the correct position so what i always do is i get my felt tip and mark the top one here and then double check that it is the correct one by phony technical which is what i did here because they were the wrong way around and this happens a lot which is why we get error codes for gas valves so any normal person within all right it's faulty i'll buy a new gas valve stick it in plug it in the same way and they get the same answer it's faulty what you should have done of course is phone technical and say right purple wires is that on the top or on the bottom and the blue one exactly the same again please do that don't just guess and think all right i've got voltage in because when i looked in the manual for this uh worcester bosch s i 25 in the flow chart it said it should be one coil is 190 ohms and the other coil is 140. and when i spoke to the very clever person in technical they said no your serial number says it should be 190 on one coil and around 390 400 on the other coil you see this is the value of phoning technical to know exactly otherwise i could be making a very expensive and time-wasting call to the spares department the next stage is going to be i need to find out where the purple and the blue plugs go onto the pcb and check the continuity and whether the coil is okay so now we're going to move down to the pcb now we can see that we've got the blue on the top and then the purple underneath completely the opposite way around so you can make a very easy logical assumption that the purple on the top will be the first two colors but there we are this is the value of checking with technical and they tell you correctly so now we need to measure it well getting a multimeter into here is going to be a challenge so what we're going to use is a special pcb available here one per person on our fault finding course on a wednesday to begin testing the gas valve we need to make sure that the meter is fine we always do this so we're going to make an x 21 22 it's refreshed therefore that's a good sign nothing wrong with a battery and we're going to test the blue wire to the gas valve which is here so we just put it in a hole put in that hole which is weight so according to the manual one coil should be 140 and the other is 190 well that's 175 so it's neither here nor there so that's a bad sign but let's just check the other gas valve here so we're just going to there and there and we'll wait for the multimeter to zoom around and we've got 400 well that contradicts the manual but it confirms what the technician technical person said one should be 190 and the other one should be 390 but 400 so this proves that this gas valve not only were the leads plugged in upside down but it's actually faulty so it needs to be replaced with the part number that technical gave us that we can make sure that we ordered the correct one from the official spare stockist thanks for watching our video and as always take care do [Music] so [Music] uh [Music] [Music] so [Music] you

Channel: Mr Combi

Views: 9,613

Keywords: Gas valve, Vaillant, ideal, prv, cold rad, balance rads, balance system, Fernox, Baxi, Vokera, Worcester Bosch, mr combi, Danfoss, Grundfos, Wilo pump, Cold rads, leak, Ferroli, Viessmann, potterton, Intergas, alpha, glow worm, fault code, no heating, no hot water, fill a system, filling loop, Honeywell, Drayton, Nest, Hive, y plan, s plan, smart controls, room stat, cylinder, frost stat

Id: GnpVBDDchDg

Length: 22min 30sec (1350 seconds)

Published: Fri Jun 10 2022