Let's take a look at a refrigerant gas leak detector. This isn't suitable for all refrigerant gases, and they have evolved there. There are new technologies, including the rather bizarrely and heated diode technology, but this is a classic ionization uh, gas leak detector because it just uses the ionizable state of the gas and the air surrounded to actually detect the leaks. So if I turn this on, that's notable.

I have covered the buzzer here with a grade tape. If I turn on, it starts beeping and if I was to actually hold this up to the microphone, you may actually hear this. Can you recite this? You might hear slight hiss. It's uh, that's the ionization effect.

Now if I get to create a little gas leak, I'm going to use Beauty in here because it seems to detect it, see how it suddenly gone up in speed, and then you can turn it sensitive to down although I've probably swamped it to a lower level, and then you can fine tune it by gradually hunting for where you get the strongest signal. I think I've just completely swapped this whole place of gas though. right enough. not really surprising.

Anyway, let's turn it off. now. the first thing worthy of note and I'm not sure I should be doing this right after I've turned it off is you can unscrew this and change the head. There is a um yeah, let's short that out because this operates at quite high voltage.

Uh, there is a little Pogo pin here springy Pogo pin and it goes against a contact in here and in here is basically a plastic insert with a sharp needle to create ionization and it measures the ionizability, the conductive conductivity of the gas surrounding it to the metal sleeve. Uh, it's powered bye oh Triple A cells four of them which I shall now remove because I'm about to take it apart. This is where having free nails would actually be quite handy. So I shall uh, pop these out and just ping them everywhere.

It's worth uh mentioning that I used to use one of these at Hussman because occasionally when the guys were busy who were doing installs of new Supermarket Refrigeration stuff and Industrial stuff. if there are any leaks that really help to have a number of people going around and if we're quiet and electrical side would help the paperwork guys find their leaks I could smell uh Freon which uh I would say well theoretically you shouldn't be able to smell freon in reality I've got an extremely sensitive uh, sense of smell and what I could actually smell. To me, it smelled like coconut. It wasn't the freon I was smelling, it was the atomized oil that was coming out of the pipes.

With the freon Freon being pretty much a brand name for the refrigerant gas, there are various types to give them their proper names, like Butane is our 600, and Isobutane, which is quite commonly used these days is R600a. All right. Okay, be careful because there is high voltage. This is quite messy inside.

I shall unplug this and I shall unplug that and I'll shall unplug the high voltage bit The Spicy bet and we can take a look at this. so I'm going to take a picture of this and then we can analyze it now. I have already had a sneak peek I took it apart as soon as I got this thing. Rather annoyingly, lots of circuitry on both sides and two chips back to back which doesn't make things easy, but I shall do I can at the very least.

I'm going to do a a block demonstration of the circuitry and what it does. so I'll do that right now one moment, please. Okay, let's explore and to be honest, I'm not going to go too deep in this as I said before, because if I have to be absolutely honest, I'm a bit disappointed in it. It's not as good as the one I used to use when I was at Hussman, which used to be like a gag account.

You know the geiger counter varies in the sort of like the clicks as you get closer to the source and it's a linear like a go. Start clicking a low frequency and then it gets faster and faster and faster. This one has literally just two levels that you have to then tune out. It's got the slow beep to show it's active and then the high speed beep to show that something's been picked up.

and then you have to tune it down to the point that goes back to slow beep and then you get closer. It doesn't do a tone. The tone would have been so much better. but here's how they've done it.

There is on the one side of the circuit board, there is well zoomed in this. On one side of the circuit board, there is the analog section which is an Lm324 which is a quad or pump um, type component or a comparator. I'm not sure that the Lm324, it's one of those and uh, it's got plenty support components around it. Um, on the other section, the end of the circuit board.

We've got the power supply section at this end and we get the high voltage section here. If we look at the other side of the circuit board, we have the high voltage. Transformer We've got the main transistor for that and we've got a Five Five Six. A Five Five Six is a dual 555.

Half of it is being used I Think with this, uh, tuning here to actually set the frequency at which this Transformer is driven just to basically tune up the optimum frequency of this to keep the power down and the other half is producing the tone. But it's got the facility from the circuitry on the other side to just switch that to the other speed tone. Lots and lots of discrete components. This honestly looks strangely complicated for what it does.

Strange. Um, the section over here is the incoming Supply it's got smoothing. It's got little five volt regulator down here and then it provides a stable set of five volt Supply Only one volt different though from the six volt battery pack. I've got a high voltage diode.

We've got the high voltage capacitor. the Transformer there's the output to the Um circuitry. It's interesting to note that initially when I took this apart I thought the red and black might be the power coming on. No, that's not.

The red and black is going to the LED um and the power is amongst all the other connections on here. It's a bit of a mishmash. The schematic: I'll show you the block schematic of it again. no great detail because it's just actually not a great circuit.

I'll give my own thoughts afterwards and how this could have been achieved. You're also welcome to give your own thoughts in the comments. So here is the battery. It's uh, four times.

AAA to give about six volts that that is Switched and then it goes to First it goes via a diode to the buzzer. I Think that's just to keep the noise off the sort of reel here. And then there's a five volt regulator. The five volt regulator feeds everything, including like the Lm324 and the 556.

the 556 has. The buzzer connects to one side with Associated Air oscillation circuitry and the switch velocillation circuitry code controlled by the Lm324 on the other side. It also has the dedicated section with the fine tunable let's just draw it in as a variable resistor fine tunable uh frequency for this Transformer the output: The Transformer has a current limiting resistor and a diode and then it's got a 2kv 4.7 nanofarad capacitor which kind of seems a bit low actually I thought they'd reused higher voltage than that and then a one Meg Ohm resistor. which means that instead of just sparking uh across, it kind of limits the current.

and it means that in the ionization head which I'll show you in a moment, it just creates that tiny purple Corona discharge in there. the glow in the gas detecting error. Depending on the current that's flowing through this, it creates a voltage differential across this resistor which is measured by the input to the Op amp and compared to one that you're presumably is the one that you're actually fine tuning with the canob. that's it.

My own thoughts here are that you could actually literally have the simplest could have been a little capacitor and a neon indicator so that uh, the voltage would build across that capacitor depending on the rate it came through the current flow and uh, it would cause the neon to flick and uh, you could then get you could get a signal of that to actually drive the Sounder just to make clicks. A bit like a geiger counter. And it went. The signal that you were actually going near a gas leak would be the opposite of the geiger counter.

It would start off and then it would get lower frequency and I think that would work I think it's just a thought Anyway The head, the test unit, The actual ionization tip in here tried pushing the plastic insert out, it did not come out. It has the flexible gooseneck which is very thin wiring, all just scrunched up here even though it works at thousands of volts which doesn't seem like a great idea. The red is going on to the outer screen and the black is going up the middle. The polarity seems quite odd.

inside. Here is a little plastic grayish whitish plastic insert with a pin going through with the flat side here and then the sharp point there that is creating the corona discharge around the tip and creating the ionization of the gas that results in conductivity to the Um metal case. Here you can change the tip. Not sure why, but when you do change it I Guess maybe the tip just wears out or it might get contaminated.

There is this springy Poco pin and uh, when you screw this outer case on, it goes on to the outer metal grounding case and also pushes that Pogo pin down. uh to actually make the connection for the high voltage I'd guess that's the reason it's got the round end to. it is just to prevent ionization there, but that isn't its own little white plastic insert. But let me show you little white plastic insert here.

not a lot of Separation There is a very strange yeah, but that is it. It just measures the change of conductivity of the air, the ability to ionize the air depending on the gas in the vicinity as I say. Not quite as exciting as hoping for. Uh, certainly if I was doing this professionally I would want something a bit more sophisticated, but if you have a system that uses a suitable gas that can be detected then this would be very useful for just a fairly cheapish home purchase one just for finding that one.

Rogue leak without having a HVAC guy run around all all day looking for that leak when you can do a lot of the legwork yourself and at least narrow it down to the area to help them and just mean they have to spend less time there Tokyo Witch uh, my time. My husband was mean in the electrical side Postman Refrigeration in Scotland and uh, it was very educational. Very useful time. but uh, nowadays because I only doubt the electrical side I was okay at electrical Control Systems I could build the panels from scratch and everything and modify existing live panels with new gear down the side.

Quite an interesting job, but nowadays I'm learning a lot about the stuff that I didn't know because it was different. Guys did the paperwork and the uh, actual pumping that charging with refrigeration, nitrogen purging, and stuff like that. and I'm learning a lot more of Chris at each vacr videos. Very good.

Channel is very thorough, talks about what he's doing at any given time, and it's another of those amazingly educational channels. Very useful and that's all sort of Industrial and Commercial Refrigeration But you know what, it's cheap. It kind of works for some refrigerants and for home use. For that one diagnostic job, it may actually pay its way.

It may actually be useful to them.