Worcester Bosch Review - Common Faults - Sherburn Plumber 

Another quality video Allen, I personally addicted to your video’s

Thank you for this video Alan, I had to deal with that exact type this week and it left me absolutely frustrated, no thought has been placed into the design of that brand of boiler, well except for the new ones. Great video.

Thanks Allen, very good honest review, keep up the good work

Good video and I agree with you. Even taking the cover of them is a pain compared to a vaillant. Nothing wrong with WB they just take longer to work on then others.

Great video again Allen it’s good to know which boilers r good and bad ones 👍👍👍

Very interesting to get an honest opinion as we have been having issues with the pressure in the system for years. we chose Worcester Bosch based on reputation. We have an Aqualisa shower that runs direct off the boiler and for many months it suddenly goes ice cold and it always seems to be lack of pressure in the boiler. Unbelievably annoying.

Great video mate 👍 I can't look even look at the right hand side hydraulic block without having flashbacks of how difficult it is to change it 💀 and that prv placement!!

Great review again, I personally work On Worcesters every day, think they are not engineer friendly tbh, prv at back, trap in front of pcb so likely hood of getting it wet, the new compacts are too compact and replacing parts are difficult, will say that worcester are fantastic at honouring there guarantee

Work on them on a daily basis.Spot on with the review.Callouts on left hand blocks,flow adaptors,not so common right hand blocks leaking.The split gas hose caught me out once(now i know to look for it).Prv shocking design to put at the back.Only plus side with this boiler is easy access to condense trap,and changing diverter motor is a doddle.The greenstar 30he was a much better made,and reliable boiler(just quiet bigger).Loving your vids dude.Keep them coming.

Thanks Allen, really impressed with your videos and the information that you provide. There are a lot of negative likes on your videos which I think is a shame, but maybe due to gas engineers who are not happy with the advice that you give, probably because they think it gives DIYers information to work on their own appliances...

Great video Alan .I work on worcester boilers a lot as there’s a lot around here , First I find that very few get serviced probably, I agree the prv is in a silly place and I remove the top of the boiler to replace so I know the clip is in correctly. Everything else I find not to much trouble.One thing I find with worcester is the parts are reasonable compared to other company’s. The tech helplines are quick to answer and the worcester cover is the best in the industry. One of my customers had a 24i that was over 11years old and they replaced the main heat exchanger free of charge because I had serviced it very year since install.I believe one of the problems that can cause the seal on the heat exchanger to start leaking is because engineers don’t use the manual air vent when they fill the boiler with water.

Great video again Alan

Great to listen to someone who knows what they are talking about without flannel!!

Totally agree with his findings on Worcester they have a good public relations dept and are advertised everywhere

I’m a fan of WB personally, I find myself repairing more Logic’s than Juniors. Obviously this boiler is now a 14 year old design (mark one) and they did make some upgrades throughout its life cycle. I agree completely they could have made certain components easier to repair but I always find Worcester good to deal with and the fact that all the spares come with the necessary replacement seals a big pro compared to some manufacturers. Find the newer i range much better to work on, and the good old faithful CDi Classic. Fallen out of love with Baxi’s since it seems Remeha have taken a more prominent role in their designs and haven’t had many dealings with Viessmann to comment on their reliability, just glad they’ve got rid of the rubber flow/return pipes! Another quality video Allen, keep up the good work! 👌

Fab video.. My right hand side plastic return unit was all fured up with limescale from a leak. I drained and replaced the right plastic unit and the flow turbine, re pressurised to 1.5bar, (the diverted valve solenoid looks really low and doesn't raise more than 3 mm) and it will not turn back on. Blue light is mostly off, 1 blue light to two red lights. What have I missed / need to do to get it to fire up. Many thanks team. Awaiting your reply.

Very good video, thank you. I've had trouble with my WB about 18months after purchase. By the time I realised it was the expansion chamber I was 1 month over the warranty - WB would not help me. Also the 'manifold' thingy back right leaked at the seam of the moulding. (very difficult to replace!) When I took it into the plumbing spares shop both the chap selling it to me and a service engineer next to me said that it was a very common fault ("I've replaced loads of them mate"). So.... next time I will stay away from Worcester Bosch and give someone else a chance

Great video. The junior version is a nightmare to work on in my experience. Someone told me that the PRV is in that position so engineers of a certain national company couldn’t drain the system by opening it!!

Thank you for a very interesting and educational video.👍🏻

We had a WB combi bolier which was recommended by our gas safe engineer , after 4 moths it developed a serious problem and kept going hot and cold , then WB engineer fitted a new heat exchanger and some other parts on warranty , come to nearly £700 ! but it still suffered the same issues and WB would not come out to look at it again as they said we had reached the limit of the warranty , then a year later the expansion bottle went and it was right at the back of the boiler ! never gain , now running a Valiant which seems excellent .

Hi Allen, another great video. Totally agree with you really hard to work on this but they changed few things in the newer models. Seen all the other videos after phex show great man👍. And it was really nice to met you at phex ( my name is Allah Hart).

I have this boiler my self - never had an issue with it since I inherited it in my house when I moved in.. I think keep it serviced and looked after it would run 15yrs plus... but after seeing more newer boilers on the market yes I’d agree the WB is not the best boiler...

Good consumer advice, when it breaks it will likely cost more to fix,

Interesting video Allen. Can I ask what boiler you prefer/recommend. I have a 10 year old WB and although relatively pleased with it I’ve heard a few people now that say they are good but not as good as others.

Many thanks for the video very helpful! Can you advise how long it should take to replace a heat pump on a Bosch Worcester combi boiler like the first one; the one on the left?

Hi Allen, what are the potential causes if the service light flashes, but 28i is still working. Many thanks

My Worcester has started making a bang when the hot water turns off. Occasionally when the hot water is running after a few mins the boiler cuts out and back on again over and over. Any ideas what this could be? The plumber said the diverter valve was fine.

What would you recommend as a replacement for my old broken system boiler, Worcester Bosch 24kw or Ideal Logic 24kw? These only an options as the company what going to install it for me has these two in stock. Need the boiler ASAP as no heating in the house. Please help with decision as I don't have anybody else trusted to ask 🙏

Great video mate! Replaced two flow turbines on friday both leaking, very common problem.

Wow amazing video and so true. Well done

Hello. I am looking to replace my boiler. Do you recommend Worchester Bosch 4000 or 1000, because I have met plenty of customers complaining about leaking issues( but this is for the past models ) ? The other option we have is Ideal , and the last is Baxi. Which one is the best.

Allen, when does the boiler museum officially open to the public? Quite a collection you have there!. Really bashing out some top content the last few weeks

I have one of the free star 28i junior boilers ,it’s just developed a small leak at the cold water entry point,just where the screw is at the bottom of the brass valve, is this easy to remove/replace ?

Last year I stopped fitting worcester bosch boilers as I have had so many problems with them and customers complaining their noisy when the system is fully cleaned. 1 Month before lockdown v1.0 I started fitting Vaillant boilers they have proven reliable

H Allen enjoyed the vidio, I am a mechanical fitter by trade and have a question ,my Worcester 25Si/30Si installed about 9 years ago has started making 4 or 5 clicks from the left hand side after the gas goes off at the end of its cycle,say when you turn of the hot tap.Strangely this series of clicks sounds louder a knock in fact in the bedroom next to the boiler. I called out a local engineer to service the boiler and asked him about it,he just said it happens all the time, said no more and left !! But it never happened for the first 7 years, so what is it,can I reset it or something ? From an engineering point of view and to stop an annoying noise what is it ? Cheers,Paul.

We have had one of these boilers. It’s lasted 17 years so probably outlived its life expectancy but the issues which are pointed out in this video have happened to ours.

I love your videos Alan but a lot of the hydraulic issues you mentioned on the Junior are avoid by fitting a shock arrestor. As per the MI. In my experience failure of the flow manifold, return manifold and flow turbine adapter is avoided when an arrestor is used. As for the kebab, usually the water quality is abysmal! Most Worcester boilers I go to for breakdowns are for maintenance/installation issues. Usually the customer hasn’t bothered with a service for years or they’ve paid someone to wipe the case down.

Just completely drained my system & after refilling it my Worcester boiler it sounds like it's just churning water & air around inside it but no hot water to taps or rads. I've bled the rads of air. Is there a screw inside boiler to bleed air in it ?

Hi Allen great video. Just a quick question. I have a Worcester greenstar 30cdi. When the temperature of the water or heating is set on full it cuts out and shows code e9. Then I reset it and put the temperature completely low and the boiler runs but not as hot water I would like. What can be the problem?

In 10 years Only had a issue with the expansion vessel. Now got a external one fitted apart from that had no issues.been serviced every year.

Which type of combi boiler do you recommend please?

Thanks for you video Allen. I've got a WB Greenstar 27CDi, 10 years old, never had a problem with it but it hasn't been serviced for 10 years. Is it still worth paying for a service or should I wait until it breaks down? In the Summer/Autumn months I keep it switched off.

Hi Alan, been watching your videos and they are very helpful, I have a Worcester Bosch and it’s loosing pressure all the time, meaning I’ve got to top it up constantly. I can’t seam to find seam to find a Gas safe technician who will just diagnose the problem without wanting to just replace the boiler. There are no leaks anywhere on the boiler or anywhere. I think it’s the PRV or the expansion vessel. Any suggestions. Would you recommend a Worcester Bosch technician.

Come across your channel recently. It's simply brilliant. In your opinion, are these any good?

New pump head fitted on worcester compact boiler but boiler still not working. Any ideas

Seems there's a Stainless Steel Plate heat exchanger buried in the back of the unit, lower down...wouldn't like to have the Boiler Engineer tasked to replaced same as it seems badly located from a servicing position...great upload...

The fan went last yea on mine , most recently problem I’ve just had fixed yesterday was the plastic components you first looked at, was cracked

Hi guys any thoughts Wooster green star 30i hot water heating but only lets small amount out then goes Luke warm but boiler heated to 88 degrees

I've had this boiler in my home for 9 years now and it's pretty much had issues every winter since it was installed. last time it went seriously wrong was two years ago and I booked the company's 1 day service visit rather than the pay through the nose monthly service plan. Not one component in the damn thing is original now. Basically I think Worcester Bosch is crap. Everything is simply running too hard and over stressed. Now I've got another leak and had to call them again. Can you advise me on what the best boiler brand is for longevity of service life and reliability, because I'm considering getting another one installed as year ten approaches. It has been a bad experience with Worcester Bosch.

Great video

Wonder if anyone else had my issue. The hot water turned on the boiler fires up no problem. However few days ago the heating was on constantly. Could not switch it off. Now the opposite has happened and can not switch it on. (My thermostat will not pair to the boiler after resetting jumpers). And the manual timer on/off/timer just makes a clicking sound and will not fure up... i believe the clock needs replacing which is my first option. But i do worry after replacement the thermostat will not pair.. please help, do you believe the clock / cdi will fix the issue?

I agree with your review. Bad design for a so called premium product, I would go Vaillant all day, but there not what they used to be. Logic Max all day for me.

I agree about the internal workings but in terms of ease of piping up, flue fitting and fixing points when installing they are brilliant though.

Have had one of these now since 2012 and I have to see its been riddled with problems on the hot water side of things. Always running ho and cold. Had a few heat exchanger replacements and many many a service but never been happy with it.

Nice video. I am not a gas boiler Installer. But helping a friend get heating working again. Even when the timer is set to ON, which should heat regardless of the time, no heating. The thermostat on the wall is set to maximum temperature. Hot water works ok. The only way he gets heating is by holding the spanner symbol button down for 10 or so seconds

Nice vid. Our hot water seems to have got less warm over the past few days. Our boiler is a 28i junior too, coming up for 9 years old. Any ideas? Thanks!

Am only a humble user so no views re servicing. Had a 38cdi for 10 years without any problems whatsoever. Regularly serviced and going strong (touch wood!) Very interesting vid though thank you.

I am a home owner and my worcester boiler is 20 years old (28Si11) I have called a worcester engineer out twice in this time, once under the first year warrantee, and again 12 years ago. As of 03/11/2021 it has locked out (flashing red once a second) I tried to reset it but all to no avail to so I will contact worcester to-morrow and hopefully parts are still available for the engineer to fix it. I think that 2, hopefully 3 repairs in 20 years is good going. I'll let you know how I got on in a few days after the engineer has been. Wish me luck!

Hi Allen, have you ever come across a greenstar 30si where the boiler won't modulate the heating or hot water, it runs in max on both? Cheers

So I see the Worcester is not that good,so wich one u recomend for your home or for a friend? Thank you for all the videos

I like that plumbers become adverse to some brands and really positive about others, it is interesting how experience is inconsistent. Maybe customers call other plumbers to fix or replace boilers fitted by the plumber who recommended the boiler which broke down or became faulty; but that is just my speculation.

Hi Allen. Could you let us know by your opinion which top boiler now days and is it cheaper to repair old one or replace. We have Worchester 24i Junior that has problem with hot water. Assume it valve, but could be sensor. No idea. Thank you.

Hello, I really enjoy your videos. Can you offer me some advice on the way I can enter the industry. I’m currently a fully qualified electrician and have my own building company which I have be running for around 18 months we do everything from a entire new build, to changing some taps. We have 4 refurbs coming up early next year for ourselves. I really want to get my own gas ticket so I can install and commission domestic heating systems. I have 18 months of experience with a gas engineer from installing boilers to carrying out servicing, fault finding and testing from a previous job at a housing trust. My apologises for the paragraph any advice is extremely appreciated. Keep up the videos!

hi can you tell me when i open the hot water the heating comes on

The fan breaks usually if for any reason it’s not been used for a while, and the ch diverted valve sticks, this is the boiler I have, as soon as it properly breaks down it will be replaced, 12 years old so it’s on borrowed time.

My Worcester Bosch Greenstar sounds like an airplane taking off on start up and when I set to max - what the heck is going on guv!? Thanks for the video.

I've got one but I'll think twice now, before buying another.

So as a consumer who may have to change their boiler in the next few years, then what manufacturer should I go for ? I always thought it was mainly down to Worcester and Vaillant with the latter edging it, although I know Allen likes his Baxi's. I guess I'd be looking for ease/cost of install, reliability, ease/cost of service and repair.

Not my favorite boiler but I’ve found replacement of the prv is made easier by isolating the cold main & cutting the feed pipe out the way. Still tricky but doable.

Any views on best boiler make currently moving into 2020? Heard the viessmann the best now

yes i agree with u theyre an average boiler i found that the hot water change over valve sticks regularly most annoying , i fitted lots only as customer likes

As a service and repair engineer. I think they harder to work on, replace parts and service (you need special brush and tools to strip down service, which a lot of the time is avoided). They need to use the same heat exchanger as everyone else. And put the expansion vessel to the side

Hi Allen, Thank you for all the videos you put out, all very helpful, My old mum has a Worcester heatslave 18/25 the problems is it runs fine for four mins, then stops for about three mins then starts up ok, then goes thru the same 4 min 3 min running and stopping on & on. Heating and H/w just don't get hot enough. Keep up the good work. Many thanks David

Hi, When you show the bottom of the boiler at 1:30 you show those screws to remove casing. I removed the casing by removing 3 screws on each side, the ones goes in 90 degrees and attaches to that plastic. Is it okay to put the casing back by using those screws or do I need a new casing? Thank you.

I consider Bosch to be a real premium product but after this I’m not sure need a new boiler soon just getting some ideas back to the drawing board

Hi I’ve got a problem with the water on a potterton promax Combi boiler. The water while having a shower is fine then it goes cold, move the control to maximum heat and it gets hot again, and so on. The shower control is fine had a new plate heat exchainger diverted valve and temp sensor but still happens. What is the next step? Regards p wilson

Correct me if I’m wrong but I believe there is no water pressure sensor on this to stop it running with low water?

Great video alan 👍 can you tell me what size fuse my Worcester Bosch green star 32kw cdi compact needs , it’s hard wired into an fcu but getting confused with fuse size needed 3amp or 13amp 😭 it already has a 13amp in but I’m worried it’s too big

Hi guys I have a greenstar 29cdi classic,it has an EA error,we have hot water,but no heating,there's also a small screen with a number reading,kicks in when I run the hot water from around 20 up to 67,over a couple of hours the number is dropping,the pressure reading is fine at 1.5 bar consistanly

I've just moved into a new house and the Worcester Bosch boiler is driving us nuts. Intermittently cuts out and displays an "EA" code. Had a couple of plumbers round but fault keeps coming back. Gas pressure has been checked all ok and condense pipe is all clear. Would you have any clues as to what could be the issue?

Any idea what might be causing a nasty smell from one of these when the hot water is running?

I agree with you. The top gasget which burns/melts away is a desigh fault. Heat ex difficult to clean properly including tight baffles. Plastic fittings prone to pinholes. Thats a design fault. Some other issues due to late or inadequate seevicing. Plate heat exchanger awkward to remove. Why dont Bosh, and other manufacturers as well as making compact boilers make larger boiler cases to facilite servicing or better still make a two case boiler with all the gas stuff in one case and the pump, plate heat exchanger,expansion divertor valve and expansion vessel in another. I'd buy one as I have space for it.

Let’s be honest, Worcester have bought the title of number 1 over the past years. The junior is one of the worse boilers they made. Plastic blocks go for fun, heat exchangers poo themselves, gas pipe splits, flap on the fan gets stuck, prv can be a right nightmare to change. I could go on. It’s true about the cover on the diverter 😂 Had quite a few juniors and cdi’s where the board fails or gets stuck in condensate mode when the power is isolated then reinstated. Them electrodes were missing the metal clip what’s holds them to the gasket 👀

Hi Allen we have a WB 15ri and its been great for 8 years(i have had to replace the Honeywell programmer-st9400 just recently but think they are common to go,but think if the new one lasts 8 year like last one then not doing bad, Oh and have changed the 3 way motorised valve-i was using aftermarket but they lasted only a year or 2 if lucky so bought a new Honeywell so fingers crossed it lasts 16 plus years like the 1st one did lol)any how on topic our boiler itself as i say is the WB 15RI and runs sweet apart from when HW and CH have reached temp and it clicks off and the fan slows down-we get a cabinet vibration-im assuming fan bearing-is this common? thanks for any help Allen...Lee.

What the red tube seen at 5:14 in your video ? Mine has perished on one end and has started leaking, I presume that this a replaceable part

I have a Worcester greenstar 28i junior boiler 2012 I think , when I put the hot water on after about 20sec the flame light go’s off and stops heating and it sounds like it’s trying to start again, it’s like starts stop, starts stop constantly until u turn the hot water off, any idea what wrong?

Hi Alan I agree with you I think they are ok when they work but they are badly designed with regards to servicing and repair work. They are very compact so they can fit into cabinets easily and that's the problem when you go to do a service or a repair as you have to access the heat exchanger and burner from above and the customer doesn't like it when you have to take her nice new kitchen cabinet to bits. Not good.

The Worcester Bosch range are nice to in stall but totally agree they are not the most user friendly to service and repair ,some of the older models can be really awakened to work on to replace parts like expansion vessel or prv,and to carry out a proper service is more Involves then Vaillant for example,but I do install Worcester more than any other boilers and I don’t really have any probs with them ,so yes there good boilers but not the easiest to work on .

i agree with them leaking.crap boiler to service.

Agree with a lot of what you say. Even the upgrade to new electrodes ie that metal clip. But as you see on that old one they go at sense probe to and no protection wb doh, "!

I have fitted Worcester Boilers over many years and never had any heat exchanger problems I do power flush them I do fit magnetic filters and I do use inhibitors also do measure the incoming water pressure pressure reducing valve if necessary also a shock arrestor yes they are awkward to work on and the prv on the junior is a nightmare for the juniors really for a smaller property and the ones I've come across having issues with the expansion vessel etc should have other supplementary ev I've experienced few problems over many years that's why I feel comfortable fitting them. Yes I am a Worcester installer in my case it's because it gives me a quiet life however there are probably people that have had a poor installation or a rogue boiler on the few occasions I have had to contact Worcester with regard to customers boiler they always responded properly left the custom with a working boiler satisfied are they worth the extra money in my opinion for the warranty.Also you are only mentioning their base model that not saying that your points aren't valid. Yes but if you get 3 gas engineers talking about boilers put them in a bag and they will fight to the death.

Is it the o rings or plastic union that leaks on these boiler's? My 1985 vaillant sine 18 t3 is still going strong its had a new main heat exchanger and expansion vessel plus gas valve and about 3 pump's all the water flow switch's rebuilt.. I think its built like a tank!

From our merchant it’s cheaper to order the gas valve to fan tube which comes with a burner gasket than the burner gasket on it’s own. Save a couple of quid.

You didnt mention a fault related to black condensate pipe, which comes from bottom of hex and goes through base of combustion case. Case gets rusty and corroded and pools up around the circumfrance of the condensate pipe exit case area. Basicly below the overheat stat, left bottom side of combustion casebelow fan. Do you know about this fault? If so have you come accross a seal/washer?? leaking? Or was there a crack in the plastic? cheers

Allen Hi, Can you help me with the greenstar 30si thermister test chart please

yes the burner gasket needs replacing as when you put probe above the burner it gives high readings and burner seal perished.

I have hot water but no heating, pressure dropped to 0, pressurised it, now on 1.5 but all radiators stone cold. Any ideas? Thanks.

I don’t agree I am not a gas engineer, I have the cdi 42 and so far very impressed it also depends if it is well installed.

So your opinions on how good a boiler is depends on how easy it is to work on and repair. Not on how well it performs ?

Interesting video. I'm a fan of WB (I'm even reading a book about how the company was formed by Cecil Duckworth) and I'm old enough to remember the old Firefly oil fired Wallflame (and later Howden Dynaflame (Firefly HDII)) boilers back in the 1960s. I'm not an installer but my impression of the WB boilers I have had experience of back in the day was that they did make good boilers. The old WB 280 Combi (non condensing) was a very good boiler, the only recurring problem we had with it was down to rust from the radiators getting trapped in the plate heat exchanger leading to the burner short cycling on hot water service. Not the boiler's fault that there was no return filter fitted to the system. There was a leak at the copper boilers union that dripped water into the programmer at about 18 years old but this was fixed by just tightening the union up. The boiler could still be used with the programmer on `Continuous'; the LCD display was unreadable due to the leak. The advantage of the WB 280 was that it could be used on an open vented system, not sure why they dropped this feature on more recent models (citing improved efficiency which made no sense to me). So when we replaced it we had to go for a basic WB boiler with WB pressurised HWS storage tank (otherwise we would have had to replace all the radiator valves, as a minimum for a pressurised system). Currently my own boiler is a WB 12Ri basic boiler which has worked perfectly for 14.5 years without a failure. The only quirk I have found with my boiler is that it doesn't like the power supply turned off frequently (which I started to do in the Summer to stop the boiler running the pump once every 24 hours as an anti seizure measure (this annoyed me because it meant a slug of cold water being fired into the warm HWS tank every 24 hours if using a 3 way mid position diverter valve). I would add that WB gas & oil boilers are consistently a Which? best buy. Edit: there was one failure on the 12Ri only a week after it was installed !! The plastic nut on the condensate siphon failed resulting in a leak; the installer gave me the upgraded part (made of brass) and no problems since. Edit: First `proper' failure July 2020. No blue light, boiler dead. New modulating fan unit & main PCB required.