How to test 3 wire flow sensors. Vaillant boiler no hot water. Combination Boiler. My first video.
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- Опубликовано: 31 окт 2017
- How to test 3 wire flow sensors on boilers etc
Shown on a Vaillant Turbomax Plus. No hot water, check out how to test this stuff.
To support this content and get access to the PDF files to go with this training click here: / heatinggeeks
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Ecellent - many thanks. More troubleshooting please - especially Vaillant Turbos!
They don't go wrong enough!!! Blocked plates, a tweek here and there great boilers.
Really informative, I'm gas safe but lack intimate knowledge on boilers. Learning all the time
Thanks. :-)
@@HeatingGeek Great videos, I've become a fan particularly as I've got an issue with my Turbomax Plus 828/2E. With the flow sensor I see you can only appear to be able to buy the 'magnet' end' My other end (the pcb end) appears to be manky and I suspect the connection is causing my intermittent issue. Would I really need to replace the whole board for such a tiny part? It's the pcb side plastic bit that connects to the sensor side that looks corroded. Cheers
I remember watching this video. I was hooked after that and told all my buddies about the channel
Thanks :-)
Good troubleshooting tips and explanation..
Thanks
Great video thank you. The fact there was no signal To the PCB means its the flow sensor as 5V to ground was good. Egg on face check always good to prevent any doubt mind.
Great video, couldn’t find instructions in Vaillant installation manual so googled it & found to it video, knew it would be a good one as Iv seen your vids before! Top notch stuff’ I’m gonna try impeller kit first
Thanks
Glad it helped. Thanks for watching. :-)
Good Info Mate. I don't do many Vaillants. Good to know.
They are all the same really. Thanks for commenting.
Another fine tutorial. Thank you for taking the time and trouble as I am sure I speak for many others who follow these tutorials with great interest.
Thanks. Thats my very first video.
@@HeatingGeekI only need a multi meter for this very issue so will only use it once would you say the cheap £10 ones on ebay are useless and a waste of money or be OK for the odd repair or is it imperative to use one more expensive and better quality to be sure of the test on the ntcs? Thank you
@@garylawton7254 I have only ever used Fluke or Testo multimeters so I can't comment on the £10 on ebay.
@@HeatingGeek is it as easy as it looks to test the thermistors?
Thanks for this. Steering me to the impeller did the trick just when I was thinking motherboard.
Glad you got it sorted. :-)
That was nice . I had same problem after 6 years of this video
Great boilers :-)
Superb tutorial ' very interesting even if your not in the business
Nicely done ' 👌
Thanks! 😃 What made you watch it? This was my very first upload:-)
@@HeatingGeek I'm a plumber and an electrician and going into do my gas hopefully your a hard worker and a fabulous teacher you deffo got a fan here
cool , got a Valliant thats droping out and cutting out , think its either the pump or flow sensor , will double check before putting the pump in . many thanks
You can use status codes to check that. Look it up. :-)
Another great video !! ...Is this on all Valliant boilers and also is it common on other boilers?
This is the same on nearly all 3 wire sensors. :-)
Hi. Thanks for the video. I went to a Worcester green star junior where the boiler fires up for hot water but doesn't get hot and so the boiler over heats. Thinking the diverter valve as the sensor is calling the boiler to fire. To be honest, I rarely do maintenance on boilers. Cheers
The diverter just comes out with 2 screws so very easy to check. I have never replaced one tbh. if it overheats it probably blocked up. Thanks for watch\ing. :-)
Excellent example in a live situation.
90% of my stuff is live.
@@HeatingGeek It's being well recieved don't know any other channels that show it live, normally in a training centre with no real life consequences. Top channel learning loads.
@@johnalderweild6442 Thanks. Its hard getting people to agree to let me film it.
@@HeatingGeek With your looks shouldn't be a problem asking mate 😂
I have changed literally one of these vaillant tmax+ flow sensors in about 15 years & I see them 2-3 times a week...
Thanks for the vid though.ill watch for the diverter vid as I can never remember which 24vdc is what wires.
I think you will start to replace these more often. The plastic impeller starts to fail now.
ruclips.net/video/K0xNZPfqQ-M/видео.html
Check out this video for the madest Turbomax Plus Fault.
trying to diagnose a fault on one of these boilers.. hot water is only warm with full flow if I close tap down does get hotter.. But boiler will eventually start kettling and cut out. works ok in heating. great videos by the way. Thanks
checked dhw hex isn't blocked.. pumps ok. aqua sensor ok.. thermistor ok.
Burner Pressure is wrong? Or a crazy fault that I have only seen twice before that I cant really explain now. Does it modulate?
gonna go back to the job today after my Son goes home.. run out of time yesterday.. was looking in Mi at burner pressure 10.8mbar and 1.8mbar on min? other than that, all I can think of is primary heat exchanger partially bloked. thanks for reply.
Did it modulate?
I don't think so as water got hotter if I closed down the tap half way? . to be honest I didn't think to check, but will check later.. sorry I'm new to break downs. I'm guessing that's why it could be over heating as it's not modulating.
Thanks, really great video. I have an issue with my valliant boiler Turbomax. Hot water is intermittent. The sensor has 4.6 vdc red to black all the time and also has that black to green as well. I took the impelar out which looked slightly warn. Any thoughts ? Thanks again.
Usually, the impeller veins start to come apart and catch in the housing. If that's not the issue then the sensor must be faulty. You cant buy it separately as far as I know. If you can send me the link. :-)
@@HeatingGeek thanks for a quick reply! I'm an electrician and haven't got a clue with boilers. I've managed to find a impeller on eBay for £7.99 and a sensor on Amazon which are coming next week so fingers crossed! Thanks again, Paul
@@SUPERSPARKYSEARS Cool. Good luck and let me know how you get on. :-)
@@HeatingGeek just thought I'd let you know your advice worked. The impeller came , I fitted it and now don't have any boiler problems. Thanks
@@SUPERSPARKYSEARS Nice one. Was the old one catching on the housing?
Thanks! Mine was showing 4.6V regardless (After taking out impeller to check it was spinning freely) , so Hall Sensor is blown - just the sort of information that should be in the servicing manual - but missing!!
I hope you have it sorted by n ow. :-)
Nice one as always.
I dont f....g understand people dislike this infos some people it cost money.
Thanks. :-)
Sorry for my english mate was writing it on wolking
@@mimo1dz38 Don't worry about it! My english is very bad too.
Hi HeatingGeek, hope you can help.
I've got a Vaillant Ecotech Plus 624 and even though we have hot water, there's no hot water icon on the display and thus, we can't change the temperature.
Vaillant themselves said this is because of a communication issue between the tank and the boiler (or a PCB fault)
Any ideas how to rectify this please?
Thanks in advance.
Unless you have a Vaillant Hot water cylinder and an Ebus control system the hot water knob doesn't do anything on your boiler.
@@HeatingGeek Thanks so much
mate. Someone else told me that too, so I've just upped the temp of the whole system, which should hopefully make the hot water a bit hotter.
68 degrees ok?
@@guyp3599 Should be ok. You will also have a cylinder stat on the HW Cylinder. That controls the hw temperature.
nice job
Thanks :-)
THANK YOU !
It's all easy once you know. :-)
Thank you very much
No problem.
HeatingGeek mate. would be the same way to tes ideal indepandent c30 switch. HW ok but no CH.
I am not sure i think the swich comes with two wires only.
If its 2 wire its a switch. If its 3 wire its a sensor. The independent is a sensor (3 wire) I think. Unless its like a Isar which uses an NTC to tell if the hot water is running.
Many thanks mate
Hey man. Did you change the body or the plastic turbine?
I changed the whole thing. However if you can get the turbine do that. Its much cheaper and takes 2 min instead of 30.
Put the part number up its you can :-)
I have a Saunier Duval which flow sensor is a frequency generator, and seems that my (always low) water pressure gets even lower on summer, and the sanitary water now doesn't run at all. It gets around 10 and 15Hz, an i didn't got it running with the oscilloscope attached to it. How can i do at least a bypass on this? I'm afraid about buying a new flow sensor ($60) and being at the same point
They all produce a frequency (hz) but they have to produce a high enough one for your multimeter/Boiler to pick it up. 10-15hz isn’t going to be enough. What Saunier Duval do you have?
Thanks for replying! It's a Saunier Duval Thematek S F 24 E, which has got a LOT of problems with the house heating system, and seems than it could be the water of the city (the say our water is a boiler killer) because now the flow sensor goes slow. I know here we have a very low pressure and flow, but i guess that the minimum 1L/minute is reached by far.
Measure the voltage. It should be just like this vaillant one. I think the flow sensor in that boiler is the same as the glowworm flexicom and vaillant ecotec. Therefore it is tested the same as this one in the video.
As i seen, the boiler itself converts the logic voltage to 17-18 volts, and even the gas system works at 24 volts. I looked the voltage at the out and with a tester hovers around 7-8 volts, so i assume is a hall sensor like ones found in some cars for its digital speedometer. Looking with an oscilloscope at the signal pin, it gets the full voltage and the 0v, with a regular patern that suggests me the coil and magnet is in good shape, and the freq is between 9hz and like 15-18hz. If i just let the pressure accumulate with closed taps, the peak flow spins the sensor to 30hz just for half a second when i open one of them, but again, i know the flow is weak here, but it should get the liter per minute (i'm likely going to test with a bottle)
Okay, i just got a 2 liter bottle filled with around 1.8L-1.9L of "hot" water in 29 seconds.
THANKS boss
So I'm getting heating fine but hot water is cycling on off every 1-2 seconds.
I get 12v red and black and with no demand get 5v black and signal wire.
With demand exactly the same readings.
Different boiler to you and we have just come back from 2 weeks away so it's a strange one.
I think the flow turbine pulse speee depend on the speed of the water flow through the impeller. which will be 5 volts. Your meter is averaging the 0v and 5 volts and shows about 2.5v
You are absolutely correct :-)
Hi mate. Had this very same problem today. Could you tell me the names of the parts that you changed please ? Many Thanks!
Aqua sensor. Thanks for watching :-)
@@HeatingGeek Thank you very much. Excellent video as always! Great use to a still relatively new engineer : ) Very thorough ans well explained.
@@georgesanders4017 Glad it helps. It was my very first video. ;-)
Hi I did change the both impeller and sensor. Had same voltage on both sides. No hot water. Any tips. Please
Is it a turbomax plus?
Thank u
thank you for watching it.
Ive read the impellor gets clogged in these, I think this is my problem at the moment as it's intermittent and as soon as I unclip the flow sensor wire from the brass aqua sensor and plug it back in it works.... I can't seem to get the impellor out though so ive ordered a new aqua sensor to be on the safe side.. any ideas on how to get the impellor out?or is that even my problem given that it's working when the wire is taken out and put back in?
To get the impeller out you have to take out the circlip. Usually, a vein has come out and is stoping the impeller turning. This won't be fixed by unplugging the hall sensor though. Bit of a weird one.
I'll make sure to update once I've found the solution to this in case anyone stumbles upon this post with a similar issue in the future
My suspicion is the wire/sensor itself is the issue so will replace the wire first to see if that sorts it
@@miffa123 Easy to replace:-)
@@miffa123 Nice one. Thanks :-)
Good explanation m8
Glad it helps.
Have have the same 4.8v, across black and red, and 4.8v accross black and green??? Whay does this mean??
If your getting this with the tap running then the sensor is jammed and needs replacing.
What electronic part did you change?
The clip-in hall sensor. You cant buy it separately but it takes seconds to do.
Thanks
No problem. Hope it helps. :-)
could you not check the resistance of the sensor before changing it?
Its usually the mechanical part. Resistance docent tell you very much on these. Once you change the brass bit you can keep the sensor and quickly check in future.
What if I’m getting 4V live and also 4V signal?
Not registering demand for HW
Then it has no signal.
Bloody sparky put 230 to 24 contact 🔥
@HeatingGeek what should he do?
Mine has 4.6v on the green all the time - why is that? When isolated then goes to zero.
Its not working??
👍
Nice vid mate..
Another way I guess, would be to check the continuity of each cable in the harness after detecting the lack of power back to the board
Which if ok should definitely point to a faulty flow restrictor..
That would work on some boilers. The Baxi duoTec (for instance) has no power during a demand but constant power at rest. See the other video I done. I was surprised myself.
😊👍👍
👍👍👍
Thanks ;-) This was my first ever upload. :-)
Quality
Glad these videos still help people
@@HeatingGeek I thought my flow sensor was shot but it was fine. I hooked it up to my power supply and to my sink. then by using the multi-meter on diode mode i could hear the sensor working as it triggered the beep accelerating as i increased the flow.
I was going to buy a new one with the stainless spring clips (for an old bosch) as one clip was broken. You can only buy the clips with the sensor (around £80). I fixed the clip by wrapping copper wire around it then soldering the wire to make it ridged. Works a treat. Now i just need to go track down the guy that ripped me off.
👍👍👍👍👍👍👍👍👍👍👍👍
It is more probable that when the test fails it is because the turbine-magnet inside the inlet tube is broken, and the magnet inside does not rotate with the water flow.
To test the sensor connect it to a 5v power supply and move a magnet close to the sensor changing alternatively N-S. If the signal cable changes slternatively from 0 to 5v then the densor is ok and the turbine inside has detached from the magnet disk
The usual failure mode is the plastic turbine cracks and fouls on the brass housing. Therefore not turning. I test these by substitution of the sensor. Takes less than 30seconds to test.
The video is more about the working principles of the unit and can be used on multiple boilers with similar sensors.
@@HeatingGeek top man!!!!! big fun Soti
@@goforit367 Thanks. :-) This is my first ever video. :-)
Can you just change impeller
Yes.
Thanks