/ News & Press / Video / How Does A Combi Boiler Work - Boilers - Diverter Valves - Hot Water Sensor
How Does A Combi Boiler Work - Boilers - Diverter Valves - Hot Water Sensor
WEBVTT Kind: captions Language: en
00:00:00.979 my name's on hats and today I'm going to 00:00:04.30900:00:04.319 show you how a combi boiler works this 00:00:08.05900:00:08.069 is gonna be an in-depth video I'm gonna 00:00:11.95900:00:11.969 take the components out and I'm going to 00:00:14.06000:00:14.070 show you how the work and neighbor help 00:00:17.51000:00:17.520 with fault-finding show you the 00:00:20.50000:00:20.510 different components in the boiler as 00:00:23.87000:00:23.880 well from fans to gas valves etc 00:00:28.81000:00:28.820 sequence and also gonna do a little bit 00:00:32.29900:00:32.309 of testing so what I'll do is I'll show 00:00:35.12000:00:35.130 you how diverter valves and tybor valve 00:00:37.81900:00:37.829 heads work as well so yeah first of all 00:00:41.86900:00:41.879 what like to do I'd like to thank trade 00:00:44.33000:00:44.340 help trade helpers sponsored this video 00:00:47.88900:00:47.899 they've got no influence on the content 00:00:50.95900:00:50.969 of the video but they've helped me to be 00:00:53.63000:00:53.640 able to do this video today so yeah 00:00:56.51000:00:56.520 trade help is a is an app for gas 00:00:59.02900:00:59.039 engineers and it allows you to do 00:01:01.72900:01:01.739 invoicing for customers the app is free 00:01:04.11900:01:04.129 they also have an option where you can 00:01:06.23000:01:06.240 offer finance there's there's like a 00:01:09.10900:01:09.119 tool as well so you can do gas rating 00:01:12.44000:01:12.450 and things like that so yeah so check 00:01:14.78000:01:14.790 out the trade help and you can download 00:01:18.14000:01:18.150 that onto you onto your phones right 00:01:21.08000:01:21.090 okay let's have a look it's not looking 00:01:23.27000:01:23.280 the boilers it's a bit hard to know 00:01:27.56000:01:27.570 where to start really um but I'm just 00:01:30.64900:01:30.659 going to try my best just to explain it 00:01:32.17900:01:32.189 in the best way I can 00:01:33.49900:01:33.509 so what does a boiler what does a combi 00:01:37.49000:01:37.500 boiler do what you want it to do so when 00:01:39.59000:01:39.600 you turn your heating on you turn your 00:01:41.66000:01:41.670 heating control up you want to get 00:01:44.63000:01:44.640 central heating and when you turn your 00:01:47.42000:01:47.430 hot tap on you want to get hot water so 00:01:50.60000:01:50.610 how does a combi boiler achieve that so 00:01:54.83000:01:54.840 first of all if we turn the heating on 00:01:57.55000:01:57.560 what happens is there's a link in the 00:02:02.27000:02:02.280 boiler here and it sends it tells tells 00:02:05.48000:02:05.490 the bar that you want heating and then 00:02:09.08000:02:09.090 you pump your pump will fire they'll go 00:02:12.83000:02:12.840 through it's equal 00:02:13.69900:02:13.709 for the gas and water from your pump 00:02:19.10000:02:19.110 pull stop pumping round you central 00:02:21.19900:02:21.209 heating pump around this heat exchanger 00:02:23.97900:02:23.989 in the top here and then the boiler will 00:02:30.50000:02:30.510 fire up and then that will send heat 00:02:33.19900:02:33.209 then to the radiators so it's got a pipe 00:02:36.02000:02:36.030 at the back there and that pipe that 00:02:37.97000:02:37.980 goes into this into the heating heat 00:02:40.64000:02:40.650 exchanger and it goes round here and 00:02:43.39900:02:43.409 down here and that will go around the 00:02:46.58000:02:46.590 heating and when you run your hot tap 00:02:49.78000:02:49.790 again more or less the same idea what 00:02:54.94900:02:54.959 you've got the pump will run again but 00:02:56.86900:02:56.879 well do know is I'll just zoom in and 00:02:59.00000:02:59.010 I'll just show you because we need to 00:03:01.64000:03:01.650 have a sensor that senses that you've 00:03:04.67000:03:04.680 opened the hot tap so just show you that 00:03:07.67000:03:07.680 now so I'll just remove the pump now so 00:03:12.77000:03:12.780 we can see what we've got there I've got 00:03:15.28900:03:15.299 a Hall effect sensor yeah just took off 00:03:19.33000:03:19.340 and that what that does is has that 00:03:26.80900:03:26.819 spins in there it sends a signal to 00:03:29.93000:03:29.940 there and then that tells the boiler to 00:03:34.22000:03:34.230 work so that's that's telling us that 00:03:36.53000:03:36.540 we've got flow through the boiler well 00:03:39.94900:03:39.959 dunno I'll just go inside and I'll show 00:03:41.78000:03:41.790 you that on a live boiler and show you 00:03:43.81900:03:43.829 how that works so in the back of this 00:03:46.93900:03:46.949 boiler here we've got a power sensor and 00:03:51.18000:03:51.190 if you see their luck is just lit up so 00:03:53.25000:03:53.260 we've run the hot sake just turn up tap 00:03:56.25000:03:56.260 back off low and then when we check hot 00:03:59.16000:03:59.170 top off we can see it's gone back off 00:04:01.14000:04:01.150 again so that's the Hall effect sensor 00:04:10.97000:04:10.980 and that's that would be on there and 00:04:15.39000:04:15.400 then what happens is your cold water 00:04:17.55000:04:17.560 mains comes into here this sense is it 00:04:21.09000:04:21.100 this turns around it gives like a 00:04:22.47000:04:22.480 magnetic field on here and that tells 00:04:25.14000:04:25.150 the boiler tells the violet to work so 00:04:31.68000:04:31.690 that's that would be in there so that's 00:04:33.48000:04:33.490 told the boiler to work now so we've got 00:04:35.61000:04:35.620 cold water going through here now the 00:04:38.61000:04:38.620 difference now is we wouldn't want to 00:04:40.68000:04:40.690 mix the central heating water with the 00:04:44.76000:04:44.770 water that you're gonna have re tap so 00:04:48.78000:04:48.790 we have to have another heat exchanger 00:04:51.39000:04:51.400 here so I'll just show you that now so 00:04:54.48000:04:54.490 in the back of the boiler we would have 00:04:56.31000:04:56.320 what's called a plate heat exchanger 00:04:59.07000:04:59.080 which is just in the back of the boiler 00:05:01.05000:05:01.060 there might be in different places in 00:05:03.24000:05:03.250 different boilers but how that would 00:05:05.58000:05:05.590 work is you'd have four pipes on there 00:05:08.12000:05:08.130 so one part of it where this one is the 00:05:12.12000:05:12.130 bottom on here these one part of it 00:05:15.33000:05:15.340 would have the central heating water 00:05:16.62000:05:16.630 going through if you like all the bow of 00:05:18.87000:05:18.880 the water from inside the heat exchanger 00:05:20.85000:05:20.860 in the boiler and then the other side 00:05:22.74000:05:22.750 would have cold water going in and then 00:05:25.50000:05:25.510 it would transfer heat via this heat 00:05:27.93000:05:27.940 exchanger and it would come out of this 00:05:30.63000:05:30.640 side hot and go to your hot apps and 00:05:33.24000:05:33.250 what that does in inside there has a 00:05:37.17000:05:37.180 little place the metal doesn't touch 00:05:40.83000:05:40.840 each other just loads and loads and 00:05:42.63000:05:42.640 loads of metal plates so be out to show 00:05:46.05000:05:46.060 you and I've not got one that's coop but 00:05:50.15900:05:50.169 if I could show you cut up you could see 00:05:52.17000:05:52.180 and what that does is it doesn't allow 00:05:54.15000:05:54.160 the water to mix from one to another 00:05:57.53000:05:57.540 sometimes when you've got a boiler this 00:05:59.90000:05:59.910 the 00:06:02.27000:06:02.280 the pressures going up all the time on 00:06:04.89000:06:04.900 the boiler and you've disconnected your 00:06:06.87000:06:06.880 filling loop sometimes these could be 00:06:08.73000:06:08.740 split inside and what that will do is 00:06:10.89000:06:10.900 that allow it yourself to top up and 00:06:12.90000:06:12.910 cause problems but thus that's not part 00:06:16.20000:06:16.210 of this video but just as a yeah if we 00:06:20.31000:06:20.320 have a look at the plate heat exchanger 00:06:22.14000:06:22.150 at the back that's where your far pipe 00:06:25.14000:06:25.150 four holes are so there's one there on 00:06:27.60000:06:27.610 this side and then same on this side and 00:06:31.05000:06:31.060 then what you need to do then because we 00:06:34.17000:06:34.180 need to control which where the water 00:06:37.17000:06:37.180 goes so if we have it on heating our hot 00:06:39.87000:06:39.880 water we have a diverter valve here we 00:06:43.37900:06:43.389 have a diverter cartridge so what I'll 00:06:45.39000:06:45.400 do is I'll take that out now and I'll 00:06:47.67000:06:47.680 show you how this works 00:06:50.42000:06:50.430 so that's diverter cartridge out of the 00:06:53.79000:06:53.800 boiler so when it's in the boiler you 00:06:56.40000:06:56.410 can just clip that off and then that 00:06:59.19000:06:59.200 comes apart sometimes top seven pins air 00:07:02.82000:07:02.830 leak different boiler manufacturers use 00:07:05.94000:07:05.950 different methods of diver in the wire 00:07:08.33000:07:08.340 and also different methods of sensing 00:07:11.52000:07:11.530 the hot water and so I'm just showing 00:07:13.77000:07:13.780 you on this particular boiler so you 00:07:16.20000:07:16.210 have a diverter head and then you've got 00:07:19.68000:07:19.690 the the cartridge and what happens in 00:07:23.46000:07:23.470 that carriage it moves there's a pin in 00:07:26.13000:07:26.140 there which I'll show you now funk stew 00:07:28.65000:07:28.660 I like to funk rye from Bucks they seem 00:07:30.90000:07:30.910 to show me a method of me being able to 00:07:32.87900:07:32.889 show you how how I can show you this 00:07:36.30000:07:36.310 work so at the moment this is in the hot 00:07:40.32000:07:40.330 water 00:07:40.98000:07:40.990 position the pin in it is pushed out now 00:07:44.96900:07:44.979 all there is I'm going to put some power 00:07:46.56000:07:46.570 on tell you and that's going to show us 00:07:48.33000:07:48.340 that now we're asking for it's going to 00:07:51.09000:07:51.100 hating I'll just show you happens to the 00:07:54.65900:07:54.669 valve I don't if you could just see the 00:07:56.64000:07:56.650 valve there so the valve was just moved 00:07:59.82000:07:59.830 and now I'll show you so this will stay 00:08:03.15000:08:03.160 in its last position but now I'll show 00:08:06.09000:08:06.100 you if we want to put it back into hot 00:08:08.25000:08:08.260 water what happens so now we're going to 00:08:12.24000:08:12.250 make it look like we want it to go back 00:08:13.62000:08:13.630 into the hot water 00:08:14.84000:08:14.850 position just check the foul so that's 00:08:27.38000:08:27.390 the diverter the diverter cartridge and 00:08:29.96000:08:29.970 what that's doing inside there that's 00:08:33.62000:08:33.630 just moving up and down as I've just 00:08:35.96000:08:35.970 shown you and it allows the water to 00:08:38.57000:08:38.580 rather go around the plate heat 00:08:40.82000:08:40.830 exchanger which then will pass over to 00:08:43.88000:08:43.890 the hot water let you hot water or if 00:08:47.30000:08:47.310 it's in the other direction it'll go 00:08:50.45000:08:50.460 around the central heating now what we 00:08:53.12000:08:53.130 also need when when the heat comes on we 00:08:56.63000:08:56.640 also need something that will control 00:08:59.00000:08:59.010 the heat obviously we wouldn't want the 00:09:01.55000:09:01.560 gas to go on full and then the war be 00:09:04.94000:09:04.950 boiling in the system so we also have 00:09:08.17000:09:08.180 temperature sensors are for misters 00:09:14.17000:09:14.180 which is that and that controls the 00:09:18.59000:09:18.600 temperature so you can have a domestic 00:09:20.36000:09:20.370 hot water sensor or you can have heating 00:09:24.11000:09:24.120 heating sensors as well and again that 00:09:27.77000:09:27.780 will control the temperature and that'll 00:09:29.99000:09:30.000 let the bard know what the temperature 00:09:33.20000:09:33.210 is until adjust the gas valve to give 00:09:37.40000:09:37.410 you the right gas in the right 00:09:38.69000:09:38.700 temperature the next thing we need to 00:09:42.92000:09:42.930 know is as as warfare any central 00:09:46.67000:09:46.680 heating gets hot the water the hot water 00:09:50.90000:09:50.910 will expand and if we've got a boiler if 00:09:54.77000:09:54.780 with this pressure gage is normally on 00:09:56.36000:09:56.370 wand as the water gets hot this will 00:09:59.69000:09:59.700 start going up a little bit now what we 00:10:03.14000:10:03.150 have to make it to absorb the expansion 00:10:07.07000:10:07.080 we have what's called an expansion 00:10:09.08000:10:09.090 vessel now if you remember an old-style 00:10:12.19000:10:12.200 heating system we would have a header 00:10:15.86000:10:15.870 tank and that header tank would take the 00:10:19.04000:10:19.050 expansion but in modern boilers we have 00:10:23.66000:10:23.670 an expansion vessel and in an expansion 00:10:26.30000:10:26.310 vessel one side of it is 00:10:28.55000:10:28.560 and then as a diaphragm in like a rubber 00:10:31.25000:10:31.260 rubber membrane there and then the other 00:10:35.90000:10:35.910 side is the central heating water and 00:10:38.27000:10:38.280 that allows the water in the system to 00:10:41.87000:10:41.880 expand now with an old open vent system 00:10:46.88000:10:46.890 if the pressure got high then it would 00:10:50.33000:10:50.340 just the tank would allow the water to 00:10:53.81000:10:53.820 open the tank if if on a combi boiler 00:10:57.20000:10:57.210 this pressure goes too high if it goes 00:11:00.98000:11:00.990 down to free then what we have is we 00:11:05.42000:11:05.430 have a PR V and we call sometimes I call 00:11:09.65000:11:09.660 it blow-off valve and that will allow 00:11:12.26000:11:12.270 water to come out of the system one of 00:11:16.25000:11:16.260 the issues we have is if if the if that 00:11:20.87000:11:20.880 blow-off Us opened sometimes the work 00:11:24.50000:11:24.510 the what reset and they can get muck on 00:11:27.62000:11:27.630 them and you may need to change them 00:11:30.05000:11:30.060 that's gnarly 00:11:31.55000:11:31.560 it's normally because rather customers 00:11:34.88000:11:34.890 put too much pressure in and the filling 00:11:37.85000:11:37.860 will pop open and put so much pressure 00:11:39.65000:11:39.660 in or it could be it might be at one bar 00:11:42.86000:11:42.870 automatic top dog to warm by on the 00:11:45.05000:11:45.060 might done a good job of that I've 00:11:46.25000:11:46.260 maintained but the expansion vessel may 00:11:50.24000:11:50.250 have lost its charge I don't mean I've 00:11:52.43000:11:52.440 no air in the expansion vessel now that 00:11:55.22000:11:55.230 could just be down to a lack of 00:11:56.78000:11:56.790 servicing and it could also be a faulty 00:11:59.30000:11:59.310 expansion vessel so on a service you 00:12:03.08000:12:03.090 would need to check that and pump it 00:12:05.12000:12:05.130 back up 00:12:05.69000:12:05.700 I normally pump up to one bar on a 00:12:10.49000:12:10.500 service and then and then the expansion 00:12:12.68000:12:12.690 vessel will be fine then so we spoke 00:12:19.70000:12:19.710 about the water side of of the system 00:12:23.24000:12:23.250 now if you have any questions about the 00:12:25.22000:12:25.230 water side of it please ask them in the 00:12:27.59000:12:27.600 comments below and now we'll have a look 00:12:29.60000:12:29.610 at the gas the gas side of it so we've 00:12:33.56000:12:33.570 asked the boiler to be on the use 00:12:35.66000:12:35.670 confluence sequence the gas valves are 00:12:38.33000:12:38.340 opened so you've got your gas valve on 00:12:40.07000:12:40.080 this particular gas valve is on 00:12:42.05000:12:42.060 bottom here and then you've got your fun 00:12:44.57000:12:44.580 on this boiler what this does the fund 00:12:47.41000:12:47.420 controls how much gas goes into the 00:12:50.42000:12:50.430 boiler and that will then go into the 00:12:54.47000:12:54.480 heat exchanger I'm just going I just got 00:13:00.11000:13:00.120 a burner here this has actually got the 00:13:03.50000:13:03.510 gas valve this is out of a this out of 00:13:06.32000:13:06.330 easement this one but this has got the 00:13:08.99000:13:09.000 fun that's got the fun there and it's 00:13:14.42000:13:14.430 got the gas valve and it's all connected 00:13:16.46000:13:16.470 onto the burner all as one piece and 00:13:21.08000:13:21.090 what happened with this is the gas and 00:13:23.63000:13:23.640 the air would mix to the correct mixture 00:13:28.04000:13:28.050 and that would depend on again going 00:13:30.98000:13:30.990 back to you temperature sensors how much 00:13:33.32000:13:33.330 how much gas you need and how much heat 00:13:35.24000:13:35.250 you need and then that would come 00:13:38.45000:13:38.460 through this burner here and then that 00:13:42.53000:13:42.540 would heat the inside of the heat 00:13:45.05000:13:45.060 exchanger I'll opened I'll open a boiler 00:13:47.87000:13:47.880 up and I'll show you the inside of a 00:13:49.97000:13:49.980 heat exchanger now 00:13:59.63000:13:59.640 so again with this we've got the burner 00:14:03.53000:14:03.540 and we've got the fun and on this one 00:14:07.23000:14:07.240 the gas valve is down here I'll just 00:14:10.56000:14:10.570 zoom in and I'll show you the inside of 00:14:12.84000:14:12.850 the heat exchanger if we look inside the 00:14:18.60000:14:18.610 heat exchanger of what's what's gonna 00:14:21.48000:14:21.490 happen in here as I said the burner 00:14:23.88000:14:23.890 allows the heat to come out into here 00:14:26.33000:14:26.340 and then this has got some pipes in here 00:14:29.49000:14:29.500 and what you've got you've got a flop 00:14:32.04000:14:32.050 pipe there in the back and that goes 00:14:34.65000:14:34.660 into the heat exchanger round round here 00:14:38.25000:14:38.260 and then it comes back out on this pipe 00:14:42.15000:14:42.160 here so what it's doing is it's 00:14:44.43000:14:44.440 transferring the heat from in here into 00:14:47.79000:14:47.800 the water you get all different types of 00:14:54.09000:14:54.100 heat exchangers in boilers this one that 00:14:57.81000:14:57.820 I've got here this is out of a Wooster 00:15:00.24000:15:00.250 now with this one we can take the burner 00:15:03.93000:15:03.940 out of the front and we can get into it 00:15:06.87000:15:06.880 service it fairly easy this is a Wooster 00:15:11.22000:15:11.230 one and we've watched the one have some 00:15:14.01000:15:14.020 connections on top and it's downward 00:15:17.31000:15:17.320 facing on this one so it's a little bit 00:15:19.89000:15:19.900 more tricky to get in sometimes as well 00:15:22.80000:15:22.810 as some Buffalo that go in there and 00:15:25.44000:15:25.450 they can sometimes be a bit difficult to 00:15:27.39000:15:27.400 get out so there's all different types 00:15:30.39000:15:30.400 of heat exchangers all different types 00:15:35.34000:15:35.350 of gas files funds etc etc but mainly 00:15:40.35000:15:40.360 they all work in a very similar way so 00:15:43.32000:15:43.330 you've got gas you've got water and 00:15:45.78000:15:45.790 you've got power and unite meet you need 00:15:48.18000:15:48.190 to transfer their heat from the gas to 00:15:52.62000:15:52.630 the water so that you get heating also 00:15:55.50000:15:55.510 that you get hot water and then there 00:15:58.17000:15:58.180 needs to be some sort of mechanism to 00:15:59.93000:15:59.940 transfer it from or a diverter valve to 00:16:04.26000:16:04.270 turn it from one where torn over and 00:16:06.36000:16:06.370 that's with more spoilers these 00:16:08.82000:16:08.830 these slight exceptions there's some 00:16:11.34000:16:11.350 heat exchangers that have the hot water 00:16:15.66000:16:15.670 pipe if you like goes directly through 00:16:18.08000:16:18.090 the heat exchanger so it doesn't need a 00:16:21.27000:16:21.280 diverter valve 00:16:22.35000:16:22.360 it doesn't need to play heat exchanger 00:16:24.42000:16:24.430 on them either then on the inside us 00:16:27.06000:16:27.070 boilers I think some of the old some of 00:16:29.67000:16:29.680 the old Vaqueros as well another one I 00:16:33.39000:16:33.400 can't remember now top Mia but they're 00:16:34.98000:16:34.990 really old by that I've got technology 00:16:37.08000:16:37.090 as well so yeah there's all different 00:16:39.06000:16:39.070 types all different types of boilers but 00:16:41.85000:16:41.860 this just gives you a little bit of an 00:16:44.34000:16:44.350 insight into into this type of boiler 00:16:47.43000:16:47.440 now I hope you found this this video of 00:16:51.12000:16:51.130 some use if you've got any questions 00:16:53.25000:16:53.260 please ask them in the comments below 00:16:55.58000:16:55.590 and I'll try my best to to answer any 00:16:59.16000:16:59.170 questions I can if you could do me a 00:17:01.77000:17:01.780 favor if you could like the video and 00:17:03.63000:17:03.640 also if you could subscribe that'd be 00:17:06.54000:17:06.550 really nice and I'll add a link up here 00:17:08.69900:17:08.709 somewhere too for you to subscribe and 00:17:12.30000:17:12.310 then I'll up some more videos down here 00:17:14.43000:17:14.440 two different videos I'll also add on 00:17:18.09000:17:18.100 these videos here I'll add a link to the 00:17:20.88000:17:20.890 trade help YouTube channel as well 00:17:23.72000:17:23.730 thanks for watching
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