How To Recharge and Check an Expansion Vessel - Combi Boiler - Plumbing

[@AllenHart999]

facebook.com/groups/Gas999/

[@ashrafalimansoor7569]

Fantastic explained on how to pressurise system.well done

[@johncollins347]

👍

[@rainsnow9174]

Allen does vessel need to be empty of water before repressuring it, and if so how would I go about emptying mine. Baxi ecoblue 28

[@marcinrybski9075]

I called specialist to recharge and service my boiler but seeing how does it work from this video is absolutely priceless. Thanks for sharing your knowledge.

[@AllenHart999]

Thanks.

[@mad-dog]

Had this problem with my combi , checked the pressure in my expansion vessel and after following all the procedures in this video . Found no pressure in expansion vessel and found the valve has a very slight leak with the spit on valve test . Put 1 bar in vessel as per sticker on vessel and all runs perfect . Will get a valve tool and new valve and fix it . You’ve saved me a lot of money …… thanks 👍👍👍👍👍👍

[@map747]

Great video. This is the sort of information and tips that can give you confidence in the fact that you now know the workings of the expansion vessel.

[@AllenHart999]

Glad it was helpful!

[@rapido2962]

What a clear and comprehensive tutorial! After living with a high pressure gauge for months I thought I had better do something about it before the cold weather really arrives. Before I shelled out for a new boiler, I thought I'd browse KZbin and came across this 'How to'. I followed the tutorial and it is now fixed! The boiler is a Worcester Bosch 24i Junior - 11 years old. It just needed the expansion vessel re-pressurising. Subscribed!

[@AllenHart999]

Great to hear!

[@rogermunns9206]

Me too! Thanks, very clear instructions, unlike some others .......

[@pgtips9236]

I have the 28i Junior & this fixed my issue aswell, the factory vessel pressure on both models is 0.75 Bar but the suggested 1Bar in this video isn''t significantly more

[@khanyekhanye7490]

I am so grateful for this video! Thanks for the clear explanation on this aspect that other videos could not explain half as clearly as you did here! 3 cheers for that!

[@andycollins4453]

Done the job …got it in …well 2 …heating on …no water down the wall outside …all’s good thank you soooo much would happily pay ..of course cheaper then the plumber ..Lucky for me mine is the same boiler - Brilliant tutorial

[@Midahed]

What a brilliant, clear and comprehensive tutorial - thank you!

[@guerillacity]

This was brilliant, as a complete novice who has no clue about boilers this helped me fix my boiler, thank you!!

[@AllenHart999]

If you have removed the case please have it checked by a gas safe engineer. Thanks.

[@namesanmanname297]

Excellent . Very Detailed Video. Thank you Allan. This guy is very much a good technician .

[@AllenHart999]

Thank You

[@alanmabey2144]

Alan,where ever you live I would like to buy you a beer!4 visits from British Gas and they still left the boiler over pressured.My original fault was a faulty diverter valve.They came back several times ,re pressurised the expansion vessel,totally incorrectly as watching this video they didnt de pressure the system full!they then replaced pressure switches,heat exchanger and they basically condemned the boiler.This was costing me time and lost wages.Following the guidance here and modifying a bike pump from Halfords (£40) I have sorted the problem. I will be sharing this video to British Gas as there engineers clearly haven’t a clue.More interested in selling boilers than fixing them.Thanks once again I am totally in your debt.

[@robi4387]

There is another video going around where a plumber said the two boiler in a house had to be replaced and it needed extra pressure vessels too £££££. I wonder if they did a volume expansion calculation or just went by 1L per kW or maybe saw the person get out of they Porsche.

[@johnboy1232]

Another very clear and concise video.I used to find at least 10% of the expansion tank valves leaking and used to carry the short core valves ( perchased from a motor factor, ) I had not seen this valve tool before ,I used to use the cross shaped valve tool with two off the pertusions cut down so I could get the thing in the more challenging positions say down the back of the boiler but leave the stubs so I could turn it,could be quiet difficult sometimes.

[@AllenHart999]

Thanks for watching and commenting.

[@AmigaA-or2hj]

Thanks for the tip! I’ve pumped up my Sime iqe 35 simplicity after following your video. The problem is that I couldn’t find drain tap. So I had to loosen the nut under the expansion vessel to drain the water out.👍👍👍

[@plumbdog1964]

Allen good video mate. One thing worth talking about is a possible blockage to the expansion vessel, more likely on the ones with flexy hose connections.

[@Mad4plumbing-ltd]

Great explanation as always on this great Channel! Never get enough of all this shared knowledge. Many thanks to Alan and all who participate ❤️

[@AllenHart999]

Thank You

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@andrewbeer9525]

What a great detailed video with clear explanations and fantastic tips too. Well done

[@Pagetsgarage]

Followed this video to a T! Very easy to follow for a Baxi boiler! Thank you again! I’ll let you know if the pressure drops over the next few days!

[@derekrose8241]

A most excellent video. Told me pretty much everything i needed to know to hopefully sort my problem. I will have a go this weekend. Thank you.

[@MrChriswelch80]

Thanks for that Allen. That was the most informative video on expansion vessels I could find👍.

[@AllenHart999]

Glad it was helpful!

[@tonygreen4896]

Thanks for this. Just successfully pumped up my Vaillant having carefully followed the steps you showed. A very easy job in the end.

[@AllenHart999]

If you have had to break the combustion seal please make sure you have it tested by a Gas Safe registered Engineer. Thanks.

[@tonygreen4896]

@@AllenHart999 Thanks but The expansion vessel was easily accessed by taking off the front cover only. Currently running at 1.8 bar cold and 2.2 full heat. Previously was heating the house but display blinking and pressure 3.2 bar.

[@michaelrose5040]

Great video for newly qualified engineers. Thankyou

[@michaelsly9180]

hi thanks for the info , my boiler pressure was increasing to 3.5 bar , drained out the boiler and checked the vessel pressure which was zero, repumped to 1 bar the boiler is now running at 1.5 bar , great help thanks allen

[@raj080288]

Is that 1.5 when the heating is on?

[@incorrect1844]

The best video on KZbin!thanks guys for taking the time to make this!

[@AllenHart999]

Glad you enjoyed it!

[@brianwood5220]

Loads of great info and tips for those learning. 👌👌

[@AllenHart999]

Thanks for watching.

[@chriscollins508]

A really useful and well presented video. Thank you.

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@Pablo-mu5yl]

I just finish the job. Thanks for the help with that video.

[@yoogeebearproductions]

Excellent video. Any videos on how to charge, discharge check etc expansion vessels on a unvented system? There are two one on my system one is white which is for the hot water and there is one red one for the radiators. If radiator expansion vessel has been charged to higher static pressure than manufacturer specification (recommendation) would this put extra pressure on the boiler heat exchanger. Causing heat exchanger to eventually fail?

[@shazadkhaliq]

I just had a Bosch engineer fix this issue on mine. Same Bosch boiler as in video. Pressure dropping then when you put it up would jump to 3 bars. He recharged the vessel. Was curious this explained why he did in more detail. Thanks

[@ArcanePath360]

My vessel valve is leaking slowly over time. Can I just replace it, pump it back up until the needle on the boiler goes back up to it's 1 bar where it should be? I don't understand having to isolate, drain down etc unless you are also putting water into the system, is that right? Thanks for the detailed video. I've ordered that valve replacement tool with some new valves which should come tomorrow

[@TheJSB007]

Amazing advice. I have a worcester greenstat cdi boiler that keeps losing pressure from 1.5 bar to 1 bar every two weeks approx. When it was installed the engineer set it up to 1.5 bar. I was always thinking the expansion vessel was at fault. Is it possible that the vessel is undercharged and is correcting itself somehow?

[@roybatty2030]

Great video, thanks but how do you get the condensation out of air side of the vessel?

[@SuperBlackguard]

fantastic video and very good knowledge to have cheers!

[@AllenHart999]

Thank You

[@SK-Cambridge]

Very extensive and helpful. well done👍🏼🙏🏻

[@AllenHart999]

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[@jogamatudo]

Allen, great video, thank you! What is the system telling me when, after pumping up the expansion vessel to 1 bar and opening up the flow & return valves the pressure doesn't go up to 1 bar and stays at around 0? The vessel seems to be holding charge at 1 bar (air mesaured). Should i just fill the system up? I am pretty sure the system is full!

[@plumbdog1964]

Good video, thanks for tip about pushing diverter motor down to drain it

[@AllenHart999]

Thank You

[@jezsmithx]

Excellent explanation. Job done

[@thanasisKrispis]

thank you for the excellent lesson!!!

[@AllenHart999]

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[@1984Scottyb]

Great video but after following the steps and turning the valves on, the pressure gauge didn't move to 1 like yours did. So what does this mean? Thanks

[@ryandow3954]

That is a brilliant video!

[@AllenHart999]

Thanks.

[@asif530]

Nice explanation. I thought the water expands and pushes against the air balloon inside. Unless I heard it wrong it was mentioned the other way in the video?

[@SalimKhan-gk1fh]

Yes it does asif, But it only pushes on the balloon membrane when it’s heated when it’s cold the air pressure would be one bar

[@iancampbell582]

Most uk and Irish oil boiler manufactures recommend 0.5 bar or 0.75 max (Grant boilers for one).All the oil systems i work on get cold charged to half a bar and never an issue.Ive noticed some oil boiler safety valves rated at 2 or 2.5 bar to lift rather than the usual 3 bar .Makes sense. I get a lot of customers over charging there oil systems because of the information on KZbin some gas guys recommending as much as 1.5 bar which starts the cycle of losing water via the prv.Then the custard is convinced they have a leak and spend hours trying to source it.lol. Which can be difficult to explain to some clients.

[@jimmyclark8229]

Great video well detailed on correct procedure .👍

[@AllenHart999]

Thanks.

[@Jamespaintsplastic]

Thanks, I really enjoy these videos. Would you also use the same method on an additional remote expansion vessel? Or would you charge it live?

[@AllenHart999]

You cannot charge one live really. Thanks.

[@davidr4533]

Excellent video Allen. But I cannot work out how to drain my Ideal Logic Plus C35 combi boiler. I find the black plastic plastic part under the boiler with the slot in it. My boiler is new but the pressure fluctuates between 1 and 2 bar (1 bar when cold and 2 bar when central heating on). On my last combi (Worcester Bosch) the pressure hardly moved when the expansion vessel was correctly pressurised. I want to check the new boiler expansion vessel pressure as I suspect installer never did that. Thanks for your excellent videos.

[@michaelprobert3607]

Hi really detailed video very good! Just wondering if the reason water comes out when you are charging with air is the balloon is expanding and pushing water out the expansion vessel?

[@AllenHart999]

Yes it does

[@raj080288]

I believe it's the condensation that has built up

[@Bisher1967]

Thanks very much for sharing this knowledge, really much appreciated.

[@EdenTan7368]

Hello Allen Thank you so much for your video, it is great helpful, but would you like to answer my question please? That’s after I repressurise expansion vessel to 1 bar and a few minutes later, the pressure keeps going up until 3 Bar, ( expansion vessel and prv are new). This caused by main cold water keeps going into the boiler, even I isolated flow and return pipe , then open drain valve, the slight water keeps going out from the boiler. So how can I stop slight water going into the boiler? Thank you

[@AllenHart999]

kzbin.info/www/bejne/jmWypKajiqp5pZY

[@AllenHart999]

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[@MrCrazycool85]

Great video sir. What else might it be if not a punctured vessel? I lost complete pressure on my boiler after hearing a weird noise while the boiler was on and when i try to re pressurise the boiler the water goes straight through the over flow pipe outside is this the expansion vessel?

[@samjones3106]

Jumping up to 3 bar is exactly what my boiler does. Then it makes a loud banging noise a few times and shuts off giving an error code followed by a hissing sound. I thought it was the pump but now I think it might be this expansion vessel. It is a Saunier Duval F25.

[@lastchance8142]

Should the pre-charge be adusted for multi-level residences?

[@mahmoudayoubi3683]

Alen you are the best

[@b1h2u3p4]

Can u hold open prv and pump up vessel that way if no drain off 🤔

[@chohanchohan8208]

OMG! Wicked Video Thanks So Much Allen and Team WB

[@AllenHart999]

Glad you enjoyed it

[@RajeshBangera-x8i]

Very good video.

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@sunnybeachwalks4k2022]

Got a a question how do you re charge an expansion vessel on a hidrotank expansion vessel with pump for mains water pressure

[@raul835]

When you think you know it all then realise you don't.. ha ha.. good vid

[@AllenHart999]

Everyday is a school day. Thanks for watching.

[@maxxwest842]

Hello, Allen - After watching this video, I checked the Schrader valve in the expansion vessel on my Worcester bosh 24 junior boiler and found it was leaking. I cannot find a replacement valve this small. Do you know where I can get one from? Thank you, Maxx

[@guinnessdublin4669]

Very good clear walk through, thank you!

[@AllenHart999]

Glad you enjoyed it!

[@dron4147]

Great video, very informative. Thanks.

[@AllenHart999]

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[@Burncash1510]

Thank you paul well explained Allen your vids are blessing thanks.

[@ChristianBHough]

Thoroughly explained, thank you.

[@AllenHart999]

Glad it was helpful!

[@trevorangieellis7497]

Excellent video

[@AllenHart999]

Thanks for the visit

[@AllenHart999]

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[@naveedhashmi4897]

Very informative Thanks

[@mrmehuddin8036]

I have a baxi 630 combi and it has a flexi pipe fitted for the filling of the tank, the main tap that supplies water from the main is always off, as always. The second tap I have left open, can this cause the boiler to drop it's water?; which I suspect it is doing with my boiler.

[@AllenHart999]

its better to close them both

[@nevergiveupever1069]

Hi Allen. I pressurised a worcester 24cdi to 0.8bar but its not holding pressure. Initially the Schrader valve was letting by. I changed the Schrader valve and pressurised the expansion vessel according to the manufacturers spec. As soon as i turn the boiler on after setting the system pressure the pressure drops down to 0.2 bar . Could it be a faulty pressure gauge or leaking diverter diaphragm?

[@ianbirch5811]

Great video , my boiler is at 1bar when its cold & goes between 1-2 bar when the heating is on , however when the pump starts from cold the pressure drops to 0.75 bar the rises slowly ! Is this normal ?

[@farukadam1696]

Excellent video both of you Regards Faruk

[@AllenHart999]

Thank you

[@freefilms10000]

must I drain the central heating section of the boiler before testing the expansion vessel pressure and if necessary it topping up ? I am confused as I understand that when the system is working properly it is quite acceptable to test the pressure in the vessel and get an accurate reading.

[@puravupadhyay2961]

I had the same thing done yesterday to my boiler. Ideally how long should it be before I need to to-pup my pressure again?

[@oleglvl]

It's annual service. Once a year.

[@ljudmillamihhalko3526]

It's good lessons for all engineers, who instead of doing job simply capped at outlet gas supply & keep your family without heating & hot water by month or more to make safe faulty boiler.

[@aeko]

Thanks for this detailed video!

[@AllenHart999]

Glad it was helpful!

[@cyril4892]

thanks allen from France

[@AllenHart999]

Thanks for watching

[@Supergreene36]

Hi, great tutorial, just one question, when isolating the flow underneath the boiler am I correct in saying thats the flow of the central heating? Thanks

[@robi4387]

Isolate flow and return, drain the boiler and pump via Schrader, to vessel label pre-charge pressure. Check the vessel holds charge. Test the Schrader valve itself. Close the drain. Open the flow and return. Bleed or let the boiler run its auto-bleed cycle. Re-pressurise the system to vessel pre-charge plus 0.2 to 0.5bar. If you are a Gas Safe registered engineer that is. If you are not and you wondering why there is contradictory advice out there regarding whether your boiler expansion tank is even big enough never mind what pressure the boiler gauge should run at then you'll just have to ask someone who is, who will then charge you explanation time if you are lucky.

[@johncollins347]

Hi Allan, can you do a video with more in depth info on expansion vessels. Particularly when adding an additional vessel to an existing system. I'm not sure exactly what effect the pre pressure and increasing the pressure will have on the existing system. Many thanks

[@practicalvoice1220]

You should run ads to get more views your videos are great!

[@AllenHart999]

How do you do that?

[@Sniperworks]

@@AllenHart999 you have to go to youtube monetization on your youtube setting and apply to be a partner. Before you can be a partner you have to have 1000 subscribers and 4000 hours of watch time within a 12 month period. Once they accept you I think there are several way of getting paid for your video. One of them is having adverts on your videos.

[@AllenHart999]

@@Sniperworks Thanks.

[@AllenHart999]

@@Sniperworks Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@Sniperworks]

@@AllenHart999 going to subscribe. Thanks for the videos

[@mohammedarif9453]

Hi I just want to ask if there is no charge on the vessel but you can see water coming from the shredder valve what is the cause thanks

[@MrStephen205]

Perhaps this worcester engineer can show what the best way of replacing the prv is please? If the expansion vessel has failed, the likelihood is that the prv will need attention too!

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@wittywoo9559]

Say the pressure is at 0 and the the boiler vessle has no charge & a new vessle is cut into the hot press .. does the vessel Inside the boiler need capping off ?

[@markb329]

Why do you have to isolate and drain to recharge, but not to check? Doesn't the system pressure affect the measured charge pressure?

[@robi4387]

Good point Tonto.

[@andy9962]

thank you sir ,this's a great help. but draine the boiler isn't easy for me since I don't want to mess up , so for get the pressure out of the boiler, instead can I draine the whole lot system water out which I know quite well

[@AllenHart999]

You should only remove the case on this boiler if you are gas safe registered or competent to do so. Thanks.

[@andy9962]

@@AllenHart999 thank you Allen, my boiler is the Worcester greenstar 28i junior, which the Expansion Vessel is outside the case,so I don't need to remove the case. please tell me would it be the same if I draine the whole lot system water out which I done it before.

[@Rucio88]

Amazing video! Thank you!

[@AllenHart999]

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[@naturelover_9211]

Very helpful video thank you.

[@AllenHart999]

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[@TheLinkedList]

Can you charge an expansion vessel when not connected up to the boiler, as in when it’s not yet piped up?

[@AllenHart999]

Yes.

[@Mandmcr]

Very helpful thank you!

[@AllenHart999]

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[@rainsnow9174]

Does expansion vessel have to empty of water before repressurising it to 1 bar

[@joefowler9600]

After draining the boiler, can you close the boiler drain and then charge the vessel? Or do you have to charge the vessel with the boiler drain open?

[@robi4387]

He said (around 11:22) charge the vessel when the drain is open and you sometimes see/hear more water coming out.

[@leecoombes8540]

Always Excellent video(s). 👍

[@richardhunt304]

Very interesting video-thanks.

[@AllenHart999]

Glad you enjoyed it

[@AllenHart999]

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[@Carzineeeeeeeeeee]

My tech installed a amtrol st-5 for my Viesman boiler (Radiant Heat only). I looked at the specs and it looks like it is pre-pressurized at 50psig. Would that cause issues with my Viesman boiler loosing pressure after a few days? (I think the pressure release valve is triggering because the Expansion vessel is over pressurized)

[@AllenHart999]

Happy holidays!

[@linear2000]

Can this job be performed legally by the home owner or does it need to be done by a qualified professional? Many thanks

[@AllenHart999]

No, Well not safely anyway. Boiler would need checking after removing the case. Thanks.

[@linear2000]

Thank you for your response

[@borninwashingmachine4582]

My world littrely almost stop , slowly and slower and finally when awaiting for one more word l slept...;)

[@AllenHart999]

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[@paulbootle3263]

Hi Allen, what does it mean when your boiler is working fine all pressures ok when just using hot water but when heating has been on the pressure drop after? Thanks

[@khanyekhanye7490]

This was my exact problem! It’s likely the expansion vessel needs a recharge . But drain the boiler thoroughly first as described on the video. I am so happy I learned from here and yesterday I resolved the problem!

[@naeemchaudhary2654]

Thanks Keep doing good work

[@kjhi98]

great video!. Anyone any idea what should the expansion vessel charging pressure of the Worcester 28i junior (mk v) be ? many thanks

[@AllenHart999]

i normally set the just less than 1 bar. 0.8 ish. Give the manufacturer a call to double check though. Thanks.

[@kjhi98]

​@@AllenHart999 ,yeh you're right fella, worcester say 0.75,so spot on .thanks alot!

[@imranawan8832]

My boiler pressure keeps dropping by around 0.1 bar each day. When the heating is on it gets close to 3 bar. Do you think the expansion vessel has lost its charge and this is resulting in the small pressure drop.

[@Nokka10]

I have the same problem. Gas fitter coming today but ive been told its likely to be the vessel itself

[@Chris-mk2fk]

Another brill video, thanks and keep up the good work! Just a quick question though, so when checking to see if the expansion vessel has the correct charge, you only have to isolate and not drain (assume boiler isolated pressure shouldn't be higher than vessell pre-charge) Been draining boiler down for years when checking pressure, sounds like I've been overcomplicating it.

[@brendanredgate4594]

Your right, I was thinking the same thing, you need to drain down, otherwise all your testing is the fill pressure if the heating system.

[@simonfrancis5458]

Yeh, me too. I dont understand why the boiler showed 1 bar but his pump gauge showed nothing. It should be the same!?? Someone needs to mention charge pressure versus system height. i.e 3 story house with boiler on the ground floor may need higher precharge

[@pjmdon87]

Do you not need to drain the boiler before checking the pressure?

[@AllenHart999]

yess

[@chriscrandon9488]

Watching the video he said that you only need to isolate when checking pressure ?? Also some of the return and flow valves under the boiler do leak so would you recommend draining on drain valve on lowest rad 👍🏻👍🏻

[@mickwalker4225]

Great video

[@AllenHart999]

Thank You.

[@trusay8338]

this is a good video .. thanks for this

[@stewartharrod8562]

Hi guys I have a system boiler Red Expansion vessel is on the airing cupboard its constantly losing pressure but nothing coming out of the PRV No leaks on the system (rads/pipes) at all

[@grahamvickers1552]

Great video 👌👍

[@AllenHart999]

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