GAS SAFETY CONTROLS IN COOKERS part 1. A gas tutorial on how controls work and how to test them.

[Music] hello my name is Derek from Tomcat caps training and this series of videos you're about to undertake is all about gas controls so we're going to be looking at all the different types of gas appliances and all the different safety controls what I used on each appliance the first the planes were going to be looking at is a gas cooker so let's have a look at the controls we can find on a gas cooker now there are lots of different gas cookers out there on the market there are freestanding cookers there are high level grill cookers [Music] there are built-in cookers and there even just Hobbs on their own but first thing we're going to look at is if a cooker has a glass lid and what safety device were looking for to protect this glass lid now the glass lid is basically a decorative part of the cooker okay but as the name says it's made of glass so the glass sees nots shatterproof okay so the heat from the rings could actually shatter the glass now then if the glass is missing all the glass is broken when you go to service a gas cooker and the safety device has not been made inoperative so basically they're not using a G clamp to keep the gas valve open or they've not jammed a piece of wood in there to to make it work then the appliance needs to be notified to have the lid replaced but if the customer is using something to keep the safety device open to allow the gas through to the hubs then that would be classes ID in the unsafe situations procedure ITM g11 so broken cracked missing and they're not using the clamp to keep the device open then just advise them to replace it but if they are using a clamp or a piece of wood or anything like that then you need to ID because it's making a safety device inoperative okay now then what we're going to do now is you show you the test for testing whether this safety device actually turns off on these cooker now again there are quite a few different devices to use to turn the gas off with a glass lid one of them is they use a plunger valve so as the as the gas valve shuts down then what it does is it closes the plunger well yeah actually makes the plunger come up and it turns the gas flow off to the gas control knobs there is also a linkage type which will just turn the gas off and then there's another type which will actually turn the gas knobs off okay so there's three different types this one is a plunger type where it pushes down a plunger to turn the gas on and the plunger comes up to turn the gas off now this is how the cooker lid safety device works on this cooker basically it's the plunger so what happens is a solid is lifted the plunger is pushed down okay so what happens is the gas comes into the bottom of this pipe here from the cooker hose and it can now pass through here where it would take it through to the hub now even with this up here the gas will still come through here this bottom port to feed the oven and the grill so this plunger is only affecting this top one and this top one is the only one what's feeding up so basically this just shuts off the gas to the four rings so none of these devices whether it's this type or the linkage type or the knob type affect the oven and the grill they just do that because that's all it's there to protect the glass lid being shattered by the hops so the way we test it is pick the smallest ring at the front okay and turn it on so this is my smallish ring at the front now I don't know whether this glass lid works or not so what I always do is just turn it down a little bit don't worry it on full burn because I don't know whether this works and then I'm gonna slowly lower okay we can see it's gone off okay so what I can do now is I can turn it on fully knowing now when I shot the gas lid it shuts off but I can see it go down okay now what I can do is I need to test all of them now that gives me the confidence now to turn off or on okay and now dropping the lid down and we can see all four go out okay set it back up and I can see the right back on they're all working and everything's tickety-boo so the first control the glass lid closing the glass lid that has worked so that's the first safety device next one we're gonna look at while we're here it's a control not a safety devices control is the gas UPS the gas schnapps they are a control okay so they need to be tested a lot gas engine is overlooked just testing the gas controls are they gassed up so basically we turn it um okay then it's given us a good flame picture we now turn it to minimum make sure it doesn't go out okay and we can see now that that hasn't got out we can now turn it back up and turn it off okay don't let's like the back one we can see its layer and we can turn it down to minimum stays lit okay and we can now turn it off via the next one turn it down to minimum stays lit stays on answer maximum up to minimum stays lit turn it off Sal weed after the oven in the grill to work but we're gonna look at those in a minute so that's just something as simple as checking whether the gas taps stiff or not working not soon enough okay stick gust up normally what happens is if the seals have gone on the oven doors okay it normally sends the heat up to the gas tap which then dries out the grease within that gas stop or it can actually melt the knob itself so if you go to a cooker and the nobbies melted or it's incredibly stiff okay then that's an at-risk situation okay because it might get to a point where you don't turn off and then that would be ID so stiff gas taps we need to check them and if they have got a stiff gassed up then first apply look at the seal around the cooker around the oven yeah around the door okay to see whether we've got heat escaping and melting the knobs the next safety device I'm gonna look at is the thermoelectric device now the other one just locked out doesn't have any thermocouples on the on the actual grill on the hub itself sorry so the thermoelectric is made up basically of two parts we've got the thermocouple which has two dissimilar metals with heat put together onto those two dissimilar metals will make about fourteen million volts of electricity which Thomas Seebeck found out way back what that does is it opens an electron magnet so the part of the safety device we're checking is the thermocouple lights and stays lit and that's creating that electric to actually keep the thermoelectric open okay so it's basically two controls two parts for this now I just quickly want to show you what the gas control knob for the hubs look like if it's got thermoelectric so this is your thermoelectric device here this is your thermocouple here okay now this is where the gas main gas comes in this is where actually here your gas nabis so as you push that in you're overriding the thermoelectric allowing the gas through here to go through to the burner okay so you push it in hold it in as it light so it allows this small about a gas to come through holds on the thermoelectric via the thermocouple being heated to distal metals making I keep going 12 to 18 actually 12 to 30 millivolts but so it's very rare you get up to like 30 millivolts so I just want to show you what a thermoelectric device looks like inside so I'll just take this brass cover off this is where this end fits under so that would go into there to make the electric current and then this so when you will override the safety device you push that down it then makes the electro the electricity which holds it in position so when you're pressing your knob in it's overriding the safety device holding it in that place so there's not enough electric to suck it but there is enough to hold it okay so that's basically what it's doing that would be attached to bear that would make the electric current you push it by pushing the knob like that it then pushes the thermoelectric like that holds it in place and then allows the gas to come through the burner and when you twist the knob there are different ways of doing it the main two ways of doing it one is a slot inside the actual barrel so the more you turn it the bigger the slot is are there is another way where it has two holes a small hole and a big hole so when you run it on maximum it's on the big hole and when you run it on minimum it's too small so that's a quick look inside what the gas valve is and you can see as you pushing that down I don't know you can see that but that's what silver I do it's banging line with the thermoelectric and that's as you're pushing that you can see it's pushing it out so that's how you override the safety device it's a simple of that so I've got to hold the knob down to override the safety to control some I'm overriding the thermoelectric part the electromagnet now the thermocouples heated up by the gas it's now made that 14 18 Mille volts of electricity which is now keeping the magnet open now when I blow this out it has a time to knock off that thermal that electron magnet so on the old cookers on the whole Bob's hops it was 90 seconds it's now 60 seconds for all okay unless the manufacturer tells you anything different so there are some gas fires which have 180 seconds so again if you got a manufacturer's instructions it will tell you that time so normally what you would do is turn it down to minimum and blow out I'm gonna blow it out on maximum so you can kind of hear the gas coming up so you can hear that gas coming out I would now start my stopwatch [Music] and that not topping just under 10 seconds okay now I can't hear any gas coming out of there and if I press the button down light it I can see there's it's not passing okay so that is completely shutting off because I can't hear any gas coming out can't smell any gas coming out and the igniter is not lighting anything so we can pretty much say that's correct and works so we'd have to do that now but all the others so again I'll leave it on the full rate so you might be able to hear it get me watch ready and again just one to ten seconds okay like the others [Music] that was five seconds that's again about five seconds so I've tested all those we can see these no gas coming out I can hear there's no gas coming out I can smell this no gas coming out so we can say the thermoelectric devices on this hob is working the electromagnet is also working and sealing off so everything's tickety-boo now the next thing we're going to look at is the actual oven burner in a cooker now there are two types of burners well not burners but the flame supervision devices there is one which is called a liquid expansion our liquid vapor fowl and one which is worked off the thermal electrics so the first what we're going to be looking at is the liquid vapor valve so let's have a look down now this cooker has the liquid expansion are there mercury vapor valve in there so they're the old really old ones that mercury in the newer older ones had alcohol in them so it's a lightly oven what we need to do is we need to press the oven knob in because we're overriding a safety device and we've got to press the knob in and then we can light it so this oven has to light in low rate if it lights in high rate that means the liquid expansion of mercury vapor valve is stuck in the open position and that would ultimate automatically make this of an ID because a safety device is not working then he goes up to high fire so I now know that this burner as Litton low rate it's expanded the file inside there with the alcohol or the mercury in there which is now open the set of bellows and the gas valve and allowed the gas to go in full burn now when we press the button in we allowed gas through what's called the bypass ring now the bypass is actually kind of a pilot light so when we press the button in the gas goes down the pilot that's what lights then that heats up the file which then opens the main gas valve which surrounds the gas in now I'm going to test and see whether the bypass is still working and I'm also going to test the actual mechanical thermostat in this oven is working correctly as well so we're going to close the job I'm going to close the door now and I'm going to turn the main oven on to slow cook off sinner what's going to happen now is the thermostat inside the oven is going to now work and that's also a file which also has alcohol in there which also affects the valve so it will expand and it will close the gas off to the valve so it will reduce it back down should due to the bypass rain now if it goes out when it goes down in temperature and shuts off the main burner that means the bypass is blocked if he doesn't go down at all then that tells us the mechanical thermostats broken so we kind of doing three tests in a very short space of time on this oven burner so let's just wait now for the burner noise to go down so I can tell then that it's gone down to the bypass ring so let's listen out for that can you it's going quieter and quieter though so it's nearly there and it now sounds like it's got off okay so it should when we open this door still be lit but in a very very low flame and it is so that means the liquid vapor valves working the bypass is working the thermostat has taken down to the bypass rate I'm just now waiting it's free to go back up to a full flame again because all the heats coming out of the oven and again that tells me the mechanical thermostat is working correctly just slowly rising up now from that thermostat the last check I'm going to do now is I'm going to now it's in low rate the burner I'm going to boil the flame out and what should happen now is the liquid vapor should cool back into a liquid and then knock off the main gas valve so we should hear the gas valve try to go into high rate because it will think that the temperatures changed it will then realize via the vapor of our vapor part of it that the heat is gone there now and it should knock off the main burner but the only problem with these is it still leaves the bypass leaking gas out so not the main burner off but the bypass rate will still allow gas through which is kind of a weird safety device okay so kind of a weird flame supervision device but that's how this works so that's what we're going to do we're going to blow the flame out we're going to end the burner go up to full rate we're going to hear it click out but it's still going to put gas out through the bypass so let's our gorilla so it's not low-rate should hear the gas come up it's now knocked off and it's lit in the bypass rate it's now gone back up to full burn so that is the final check for this now the flame supervision device in this oven burner is a thermoelectric rather than a liquid vapor so the test for that pretty much same so I'm going to turn it all the way on to maximum well I'm pressing the button in now and you can hear the gas coming out but this time the oven lights in high rate rather than low rates okay now what I'm going to do now is I'm going to turn it down to simmer again so you can see it's in high right we're going to turn it down to simmer I'll slow cook I need to close the door so hopefully through the glass now doesn't steam up which is doing will see that the burner will go down once the burn has gone down that means it's up to temperature so that means the mechanical thermostat is working then I'm going to blow out the flame and it should on the thermoelectric knock out and even when I press the igniter again it shouldn't rely until I press the bottom back in okay let's see if that works so first of all we need the flame to go down and then that's going to prove the mechanical thermostats working just starting to go down there so as a gas engineer one of the first things you need to do really is find out before you start working on the oven itself is it a liquid vapor is it an old liquid vapor or is it one of the new thermoelectric ones so even when a gas engine is ticking is a reassessment or it's a new guy tick is the initial assessment my advice would always be before you start working on that cooker when you're doing your visuals have a look and see what safety device it have does it have thermoelectrics on the hob is it a liquid vapor or a thermoelectric credibly important these things still look good all the way down yet well you come here the gas is reduced it's going down now just as a glass clears okay it's nearly gone all the way down there so I know the mechanical thermostat is working so what I'm going to do now is I'm going to blow it out hopefully we're going to hear this click and this click has to be within 60 seconds once the click has happened I'm going to try and light it it should look like because the thermoelectric should knock it off completely so this is being kept alive now by still by the bypass rate but the thermoelectric device is now both the bypass rate on the lot unlike the liquid vapour so a go-go [Music] there yeah you had to click so if I try and light it now each shouldn't light and it isn't doing so I know the thermoelectric is not tough but we've got pretty close I don't know exactly now and one you think was about 30 35 seconds so we were still welling with the 60 seconds so that's how you test the thermoelectric device on the oven burner so bar gas rated this oven and when a gas rating of them we always have the door open because we don't want the thermostat effecting when you gas rating the burner itself that's the main checked done on this type of burner next we're gonna have a look at the safety devices on grills again two types of grills this is the high level grill and then we've got the low level grills let's have a look at the high level grill first now this grill has a thermoelectric device in it so again I've got to press the knob in press the igniter to light it leave it for a few seconds let my finger out and now it's controlled by the gas tap on the front so I can have it on high or I can have it all oh okay there is no temperature control on this it's just basically more gas or less gas but it is the safety device on this one is actually the thermal electric device this high level grill only as ignition it doesn't have any kind of safety devices whatsoever but still you control it on high and low by the use of the gas tap on the front there are no thermostats in this assault a slow level grill is slightly different the burner is slightly different but again there's only ignition now they said there is no safety devices and the only way of controlling the heat fire there's no high so this is a low level woman now this low level grill is same as pretty much the high level grills upstairs on the burner side so again there's no thermostat again there's no safety control just ignition again we're only controlling it by the actual turn up here so that's high house low don't to the road up okay but you can hear a fan running on this one so basically what should happen is when I close the door the fan should stop and not that you can see the burners got out but if I open the door again you can see that the actual gas has gone out so this has a safety device to close the gas stuff because the door shut but doesn't actually shut the gas off when you reopen the door now that's our video on the controls used for gas cookers so if you've enjoyed this video why don't give it a thumbs up I'll leave a constructive comment down below if you not subscribe to our YouTube channel yet they get subscribing and don't forget to hit that notification bell because we released videos every Wednesday next video coming up will be this controls for a fire so don't miss that one so all I've got to say is thanks for listening thanks for watching and tune in next week for this video on the safety controls for gas fires good guys

Channel: Tomkat Gas Training

Views: 33,314

Rating: 4.9295335 out of 5

Keywords: gas safety controls, how does an oven work, how do you test an oven burner, gas controls for a cooker, how to test gas safety controls, testing gas controls

Id: 9y2jhA_pToI

Length: 28min 43sec (1723 seconds)

Published: Wed Jan 29 2020