Nightmare time with Worcester Bosch repairs

[Cazza]

Hi

Was wandering if anyone can tell me if a competent boiler repair man should be able to detect a leak on an isolation valve to the boiler fairly easily. Worcester Bosch repair men came out 10 weeks ago to repair what was a leaking left flow unit. They also took boiler apart and replaced a few other things just in case that could leak (prv and expansion vessel). To cut a long story short I've had continuing pressure loss since they came out, one bar every 2 weeks. They kept telling me it couldn't be the boiler but I kept running isolation tests which proved to be the boiler. In all they've come out 7 times and 4 times there has been a leak on the left and right isolation valves. They tried tightening one, then replacing both washers, then replacing the right valve and now hopefully they are coming back to replace the left valve which still looks to be leaking.
Their attitude has been horrible, they are now unwilling to come out again they said if there is a continuing pressure loss after their visit today. I've had this worry for 10 weeks, had to run 4 isolation tests, had to take 8 days off work for their all day appointments getting up very early. I don't think I should have had to go through this. They kept telling me I had practically a new boiler so not to worry about the pressure drop. I think they should have ran some sort of isolation test on the second visit to determine where the leak was and properly diagnose it first (on the second visit they actually put in a new heat exchanger instead of finding the valve leak). Can any competent boiler repair man tell me what they think please?

 

[Rob Foster]

Hi

Was wandering if anyone can tell me if a competent boiler repair man should be able to detect a leak on an isolation valve to the boiler fairly easily. Worcester Bosch repair men came out 10 weeks ago to repair what was a leaking left flow unit. They also took boiler apart and replaced a few other things just in case that could leak (prv and expansion vessel). To cut a long story short I've had continuing pressure loss since they came out, one bar every 2 weeks. They kept telling me it couldn't be the boiler but I kept running isolation tests which proved to be the boiler. In all they've come out 7 times and 4 times there has been a leak on the left and right isolation valves. They tried tightening one, then replacing both washers, then replacing the right valve and now hopefully they are coming back to replace the left valve which still looks to be leaking.
Their attitude has been horrible, they are now unwilling to come out again they said if there is a continuing pressure loss after their visit today. I've had this worry for 10 weeks, had to run 4 isolation tests, had to take 8 days off work for their all day appointments getting up very early. I don't think I should have had to go through this. They kept telling me I had practically a new boiler so not to worry about the pressure drop. I think they should have ran some sort of isolation test on the second visit to determine where the leak was and properly diagnose it first (on the second visit they actually put in a new heat exchanger instead of finding the valve leak). Can any competent boiler repair man tell me what they think please?

I understand from my links in hvac land that WB have got problems. Their team is 300 strong but due to quality issues with their boilers in past few years the waiting time has increased dramatically and properly trained engineers are in short supply.

 

[oz-plumber]

If it were me and I was trying to prove a point, I would:

Isolate the boiler from the heating system.
Plug the PRV valve outlet with a 'plug'
Using a test bucket, pump the boiler up to a pressure of 3 bar, ( the boiler should be able to stand the pressure of the relief valve setting ) and have a look around for leaks.

That would be the only way to determine if the boiler has a leak.

 

[Cazza]

If it were me and I was trying to prove a point, I would:

Isolate the boiler from the heating system.
Plug the PRV valve outlet with a 'plug'
Using a test bucket, pump the boiler up to a pressure of 3 bar, ( the boiler should be able to stand the pressure of the relief valve setting ) and have a look around for leaks.

That would be the only way to determine if the boiler has a leak.

 

[Cazza]

Thanks for your replies.
I don't think they carry out diagnostic tests very well and just replace a load of things that are known to leak and call it a day. Yesterday they've put a large gauge on the radiator and one on the boiler. Pumped it up to 2 bar. They wanted to come back yesterday after only 3 hours, which I knew would show nothing. I insisted a later time. They're coming back this afternoon, both gauges have dropped about 0.15 of a bar that they are yet to see. The left isolation valve on boiler looks a little wet. Maybe their is also a small leak somewhere on underfloor pipes. But definitely also the boiler has leaked. I told them over the phone the boiler gauge has dropped. They've told me they won't come out to me again after today and coming to collect their things. Even though last week they promised if the gauge dropped on the boiler I need not worry it was their problem to get to the bottom of it. So they have gone back on their word, they said they won't charge me and that i'd have to use another engineer. I just hope they at least replace the left valve.

 

[Cazza]

Thanks for your replies.
I don't think they carry out diagnostic tests very well and just replace a load of things that are known to leak and call it a day. Yesterday they've put a large gauge on the radiator and one on the boiler. Pumped it up to 2 bar. They wanted to come back yesterday after only 3 hours, which I knew would show nothing. I insisted a later time. They're coming back this afternoon, both gauges have dropped about 0.15 of a bar that they are yet to see. The left isolation valve on boiler looks a little wet. Maybe their is also a small leak somewhere on underfloor pipes. But definitely also the boiler has leaked. I told them over the phone the boiler gauge has dropped. They've told me they won't come out to me again after today and coming to collect their things. Even though last week they promised if the gauge dropped on the boiler I need not worry it was their problem to get to the bottom of it. So they have gone back on their word, they said they won't charge me and that i'd have to use another engineer. I just hope they at least replace the left valve.

 

[Cazza]

I just looked at both boiler isolation valves and they both still looked wet on top. I did a tissue test and it was moist on both of them. Even though they'd changed the right valve yesterday. Could it just need tighening up or should they have used something else in the nut to stop it leaking?

 

[oz-plumber]

0.15 of a bar is too indecisive.

Do you have plastic piping or copper piping. Plastic expands to pressure and hence reduce pressure readings on gauges.

That amount of pressure drop could be the temperature of the water lowering also.

It could also be attributed to the bladder in the expansion tank adjusting to the set pressures.

The only way you are going to get to the bottom of it is to test the boiler separately and the heating system separately.

 

[Cazza]

Thanks for the information. I've got a mixture of plastic and copper pipes. Upstairs where the boiler is mostly plastic. The boiler/ heating had been cold over night before running the isolation test so not cooling down. I thought it strange the boiler and radiator gauges have both dropped at almost the same rate, they are being tested separated with the boiler isolated from the radiators (valves turned to horizontal). Unless the valves leak inside which would explain the same pressure drop.
There is definitely moisture on the boiler valves though, could these account for a 0.15 bar pressure drop?

 

[Millsy 82]

Have they isolated the boiler from the system? A 0.15 bar drop could just be a temperature drop.

Small leaks are notoriously tricky to locate as a lot of pipework and fittings are hidden in floors, walls and ceilings. The isolation valves under most boilers are a nightmare touch them at your peril. Can almost guarantee when you touch them they will start leaking.

Worcester are well known (especially round me) for just throwing parts at the boiler as the engineers get penalised for return calls I believe.

When you do an isolation test how long do you leave it? Do you make sure the water temperature is exactly the same both times? Breakdown engineers are usually very time limited and especially this time of year so they can't just sit there for 12 hours to test.

 

[Cazza]

Thanks. Yes they have isolated it from system. They have a large gauge on both one radiator and the boiler itself. The boiler/ heating was cold over night so no temperature drop.

I think this is whats happened. Instead of just replacing the leaking left flow unit they also replaced lots of other things too but needed to touch both isolation valves to take boiler apart. This has then resulted in them leaking ever since, which they've never spotted. I've picked the leaks up by doing my own isolation tests (3 times!).

They only wanted to run the isolation test for 3 hours yesterday. I asked them to come back today (at first they didn't want to come back until Monday but too cold to be without heating or hot water that long). So now the isolation test has ran for 26 hours.

I think its the left and right isolation valves leaking. Should I ask them to use thread seal on the valves? Would this help, as even the new valve looks to be leaking.

 

[Welder]

Thanks for your replies.

Cazza. You have to take a step back and look at this much more logically. The hand wringing frustration, although understandable, is not engaging people on your behalf.

Personally, I'd write to Martyn Bridges who is head of technical at WB. Keep the letter factual.

For example, 10 visits withOUT definitive understanding of whether root cause is boiler or pipework. Need more experienced/competent engineer by x date otherwise I shall be forced to engage my own 'expert' and send you the bill if it turns out it is a boiler fault.

Sorry to be so 'brutal', but stop messing about on here and get something moving with those who can effect positive change. 😉

 

[Cazza]

Thanks for your thoughts but Worcester Bosch have already told me they won't help me no more and are refunding my money. I've got the Worcester guy turning up this afternoon and he is supposed to be replacing the left valve (i've been told) and then he is going to take his gauges and leave and they won't come back (great customer service hey! not). Ideally I don't want to have to organise and pay for another engineer to come out just to sort the valves out, which i'm sure is the only cause of leaks. As the right new valve they replaced yesterday is leaking I just wanted some advice on how they can sort that out whilst he is here this afternoon.

 

[Rob Foster]

Where abouts are you, when they all get in then something might gel
centralheatking

 

[Cazza]

Bristol

 

[Welder]

Thanks for your thoughts but Worcester Bosch have already told me they won't help me no more and are refunding my money. I've got the Worcester guy turning up this afternoon and he is supposed to be replacing the left valve (i've been told) and then he is going to take his gauges and leave and they won't come back (great customer service hey! not). Ideally I don't want to have to organise and pay for another engineer to come out just to sort the valves out, which i'm sure is the only cause of leaks. As the right new valve they replaced yesterday is leaking I just wanted some advice on how they can sort that out whilst he is here this afternoon.

I'm out and I completely get why WB have refunded you TBH.
Good luck cos your'e going to need it.

 

[Welder]

I am not allowed to mention Top Up Mate from Flowflex
centralheatking

🙄 The bl00dy thing leaks Rob!
Why would she want to keep pouring water into it?

 

[Rob Foster]

Bristol

Kevin Davy Plumbing and Heating Bath is a good outfit
might be KL Davey..if you do get him let me know
his dad was real old school he is fully apprentice trained
and as old as me centralheatking

 

[Riley]

Is this a warranty call or is it a fixed price repair

 

[Cazza]

Is this a warranty call or is it a fixed price repair

 

[Cazza]

It was a fixed price repair.

I know they are refunding me but they created the new leaks. They also promised to get to the bottom of it which they are not.

Yorkshire Dave I don't understand your comment at all. Unless of course your competency level is the same as Worcester Bosch as you think the customer should find and pay for leaks started by engineers

 

[Riley]

Don’t get snarky. I think his point is you need to go higher as was originally said. Arguing the toss with the helpline and engineers who are just there to do a job isn’t going to get you anywhere. Simple fact is yes there could be a leak finishing at the isolation valve however it could be coming from anywhere above. Take what you’ve told us re time off work etc and multiple times where you’ve had to do things yourself and write to the CEO. I’d say for your time wasted they should be contributing to a new boiler or be resolving your issue. Be as blunt as that. They have entered into a contract with you and shouldn’t be allowed to cancel it without penalty

 

[Welder]

Yorkshire Dave I don't understand your comment at all. Unless of course your competency level is the same as Worcester Bosch as you think the customer should find and pay for leaks started by engineers

Ho ho ho ho ho....

It's little wonder so many people are queuing up to help you. Your friendly, engaging personality and razor wit shines through. #Irony

I withdraw my good luck comment because I'm genuinly glad to see you are reaping what you've sown.

 

[Cazza]

Thanks for the support Riley. I think your comments have made me think

Ho ho ho ho ho..

It's little wonder so many people are queuing up to help you. Your friendly, engaging personality and razor wit shines through. #Irony

I withdraw my good luck comment because I'm genuinly glad to see you are reaping what you've sown.

 

[Cazza]

I just didn't like your comment that you "totally understood why WB were refunding me". Sorry if I took it the wrong way, I thought you were being rude and were on their side. WB has put me on edge, after how mean they were yesterday. But I thank you for your previous post and contact name.

Riley thank you for comments, most appreciated. I think perhaps I will write to the CEO then. All I want at the moment is the boiler fixed but it doesn't look like that is going to happen.

 

[Riley]

Unfortunately, much as we hate it, we live in a society of he who stamps their feet hardest gets things done. I don’t agree with it but such is life

 

[Rob Foster]

Don’t get snarky. I think his point is you need to go higher as was originally said. Arguing the toss with the helpline and engineers who are just there to do a job isn’t going to get you anywhere. Simple fact is yes there could be a leak finishing at the isolation valve however it could be coming from anywhere above. Take what you’ve told us re time off work etc and multiple times where you’ve had to do things yourself and write to the CEO. I’d say for your time wasted they should be contributing to a new boiler or be resolving your issue. Be as blunt as that. They have entered into a contract with you and shouldn’t be allowed to cancel it without penalty

Contractually WB might well be in breach of their contract, especially
as they are actually involved in an on going dispute. Its like saying your car insurance is invalid because you have had a crash. go get them stay cool and WIN . keep us informed get someone else in
pay them and claim it back. ring trading standards you pay rates
Rob Foster aka centralheatking

 

[Rob Foster]

Contractually WB might well be in breach of their contract, especially
as they are actually involved in an on going dispute. Its like saying your car insurance is invalid because you have had a crash. go get them stay cool and WIN . keep us informed get someone else in
pay them and claim it back. ring trading standards you pay rates
Rob Foster aka centralheatking

it would be good to get feed back...thats why we do,this
centralheatking

 

[sammathias]

Vaillant.

 

[Cazza]

Thanks. I've drafted a letter to Martyn Bridges. Worcester Bosch came yesterday and I told him that the left isolation valve is still visibly leaking (even with new washer) and the new right one is also leaking (very strange but a tissue test showed it was). I asked him if he could put some thread seal in the new nut to stop it leaking. He replaced the old leaking left valve and put thread seals in both, he also said he changed a valve or something above the right isolation valve in case it was leaking down onto to it. He also used some joint sealer for pipes or something (can't recall what name he gave me). So he said they won't be leaking anymore (5th time lucky?!). Anyway this morning, before the heating came on, I tested both valves with tissue and they both seem to be dry. I'm hoping this will help the pressure drop problem. Although I'm not sure if it could account for a 0.2 bar pressure drop a week.
If the boiler is finally fixed and this works I will leave it, as they haven't charged me. But if the boiler still seems to be losing a lot of pressure (I may run another isolation test myself if needed) then I will send off the email to Martyn Bridges at Worcester Bosch. Because they should leave me with a working boiler and not a leaking one.

 

[Riley]

Keep in mind that a 0.2 bar pressure drop is not a lot and hence why such a small leak is often undetectable.

 

[John.g]

Thanks for the information. I've got a mixture of plastic and copper pipes. Upstairs where the boiler is mostly plastic. The boiler/ heating had been cold over night before running the isolation test so not cooling down. I thought it strange the boiler and radiator gauges have both dropped at almost the same rate, they are being tested separated with the boiler isolated from the radiators (valves turned to horizontal). Unless the valves leak inside which would explain the same pressure drop.
There is definitely moisture on the boiler valves though, could these account for a 0.15 bar pressure drop?

A 0.15 bar pressure drop isn't IMO just a drop of water from a boiler that's isolated.
If one assumes a 8 litre expansion vessel with a pre pressure of 0.5 bar and a filling (test) pressure of 2.0 bar, then the boiler will lose 0.21 litres of water. If the pre pressure above is 1.0 bar then the boiler will lose 0.28 litres of water for the same 0.15 bar pressure drop.

 

[Cazza]

Yes this is what i've been worried about since as when I asked the last Worcester guy if those tiny valve leaks could have accounted for a 0.15 bar drop in the test he said in his opinion he thinks it could. Which mean't he knew a lot of other people would disagree. Those two valves only had a tiny drop of water on them. The expansion vessel was pressured to 1 bar. The water pressure was put to 2 bar for the test. The weird thing was both the boiler and the radiator gauge fell by 0.15 bar, even though the boiler was isolated. Because I was told 1 bar is like a coffee cup I was thinking 0.15 of a coffee cup is a lot more than a tiny drop with the boiler off (i.e. not evaporating). But everything has been replaced on the boiler that could leak, including the expansion vessel. But like an earlier member said 0.15 bar could be accounted for by a settling down pressure release within the expansion vessel (or within the plastic pipes for the radiators). The only other thing I can possibly think of if they have put in a faulty new heat exchanger or expansion vessel, but that is unlikely. Or is there a leak on my pipes? The Worcester Bosch man did say the isolation tests that i'd been doing weren't reliable because the isolation valves can leak inside so i'm really seeing a drop on my radiator system (but I don't know if he was fobbing me off and I thought his testing with large gauges was supposed to rule that out, hence the whole idea of it)

 

[John.g]

If the Bosch man suspected the boiler isolation valves then surely he could have bled a drop of water off the rads with isolation valves closed, if both pressure gauges then fell together then the isolation valve(s) are passing.
I think that you will have to get someone to rule the boiler in/out, but I can tell you that with a 1 bar pre pressure, and test pressure falling from 2 bar to 1.85 bar that a 6 Litre E.vessel will release 0.21 litres, a 8 litre; 0.28 litres & a 12 litre; 0.42 litres.
In one of your posts you said the pressure was falling 1 bar every 2 weeks, this relates to a leakage (somewhere) of 2.0, 2.67 or 4 litres respectively, boiler or system??.

 

[Cazza]

Thanks John. Yes that is true! He could have tested the isolation valves that way.
After the initial works they did it was dropping a bar every 2 weeks. Several visits later and isolation valves tightened / auto airvent changed/ expansion vessel pressured from 0.4 bar to 1 bar it was more like 0.4 bar drop every 2 weeks or say a bar a month. So something dropped the rate of pressure loss by half. Since he was here 2 days ago the pressure gauge has gone from 1.5 to nearly 1.3. But he did warn me that there would be some air in the boiler so expect an initial loss. Because they say its got to be my pipes just before he left he said I should let it find its only pressure level, and let it go all the way down to 0.5 bar if necessary as that might stop the pipe leak (if there is one). But I don't really want to do that because that will take another 4 weeks and what happens if it drops lower than 0.5 bar then I have a problem. It will be too late to complain to Martyn Bridges by then.
I've turned my boiler off this morning and thinking of running another isolation test for 36 hours on the boiler. As any air should have autovented by now. Also with the two new islation valves I'm guessing they won't leak inside to the radiator pipes.
I will let you know what happens in 36 hours and if the boiler drops. My guess is that it will as I agree around 200ml of water is what must have leaked. But there is no pooling of water under the boiler. So what does that leave that could leak away from the boiler without me seeing? .... prv, expansion vessel or heat exchanger? All of which are new apparently.

 

[Millsy 82]

Every time you do work on a boiler you allow air into the system. If you fully drain a boiler it can take a few weeks for it to settle back down again and get rid of all the air. So a 1.5-1.3 drop the day after they have carried out.

Just leave the boiler alone don't do any isolation tests tissue tests anything for a couple of weeks and let the air settle then look again.

The chances are with everything you say they have done to your boiler it WONT be on your boiler.

 

[Cazza]

Thanks for the information. I'll leave it then for a couple of weeks.

 

[John.g]

If you could shut off the air vent like in this interesting thread it might tell something but you probably can't if the auto vent is inside the boiler casing (not GSR).
Pressure drops when AAV open

 

[Millsy 82]

If you could shut off the air vent like in this interesting thread it might tell something but you probably can't if the auto vent is inside the boiler casing (not GSR).
Pressure drops when AAV open

I wouldn't advise that as it's inside the boiler.

 

[Riley]

If you could shut off the air vent like in this interesting thread it might tell something but you probably can't if the auto vent is inside the boiler casing (not GSR).
Pressure drops when AAV open

Yes please be careful on what you post!

 

[Aire]

A 0.15 bar pressure drop isn't IMO just a drop of water from a boiler that's isolated.
If one assumes a 8 litre expansion vessel with a pre pressure of 0.5 bar and a filling (test) pressure of 2.0 bar, then the boiler will lose 0.21 litres of water. If the pre pressure above is 1.0 bar then the boiler will lose 0.28 litres of water for the same 0.15 bar pressure drop.

Quoting specific amounts of water lost is a little daft given that the amount of water it takes to drop pressure varies more on system volume than the size of the expansion vessel. I know the 2 go hand in hand but the standard vessel within the boiler is good for up to around 100 litres of water. Has op specified how many rads she has? A 5 rad system running at around 50 litres is going to show a much bigger pressure loss with a cup full of water compared to a 10 rad system running at 100 litres. I've had a system where the combi was in the loft in a bungalow, and bleeding a cup full of water out a radiator was enough to drop the pressure to nearly zero. So in my opinion, depending on the size of OPs system, yes a few drops from the isolation valves at the boiler is enough over a week, to drop 0.2bar of pressure.

 

[Cazza]

Thanks for all your thoughts everyone. I have 10 radiators. 4 of them are only a 1.5 foot wide tho. There is a large 4ft one, two 3ft, and three 2ft.
I did not know it takes 2 weeks for any air to vent out of the boiler. That changes everything. Perhaps this was accounting for the pressure loss I saw shortly after the recent repairs, on top of the isolation leaks. No one from Worcester told me this. After they came out the first time it went from 1.5 bar to 0.5 bar within 2 weeks. I doubt that was just air venting. But maybe after they re-pressurised the deflated expansion vessel that fixed that and then any continuing drops in pressure (0.4 bar a week) was just air venting from the boiler. I think i'm going to have to let it settle. If it is still dropping in 2 weeks time then i will run another isolation test. But now I am wondering how reliable isolation tests are if there is auto air venting. I will have to run the test without filling it back up with water (as that would put air back in the boiler)

 

[Cazza]

I forgot to say I only use 5 out of those 10 radiators tho. Keep the other 5 off.

 

[John.g]

I wouldn't advise that as it's inside the boiler.

I did point that out in my post above and IMHO the Bosch service man should have shut off the air vent, stayed around for a few hours and if the pressure increased slightly then vent again.
I spent many years running and maintaining large industrial boilers and various pressure vessels and carried out many pressure tests for leakages, some of these vessels had auto vents but in all cases once all the air was expelled then the auto vents were shut until the pressure test was completed.

Yes please be careful on what you post!

Double post.(above, mine)

 

[J Davies]

I find all the above interesting as someone trying to decide between a WB Highflow 550 and a Viessmann 222F. One installer who quoted for me (and who installs both makes) told me that WB customer service was really good, which was making my decision difficult as for various reasons I prefer the Viessmann boiler over the WB. The comments by Rob F now make me wonder if there is another reason the installer wants me to choose WB and not Viessmann. Perhaps a better profit margin, or maybe Viessmann customer service is worse than WB. Are WB easier to install than Viessmann? Decisions, decisions!

 

[Cazza]

I don't know anything about Viessmann but I was speaking to a boiler service man a year ago and he said he only now installs Valliant boilers as he has had too many problems going wrong with the WB. In my first house I had a Valliant and it was fine (but I was only there 7 years). I don't think i'd get WB again. Although the new WB ones come with a 10 year guarantee, but even still if you can't trust their service men to get to the bottom of any issues what good is their guarantee, just a load of stress.

 

[Millsy 82]

I did point that out in my post above and IMHO the Bosch service man should have shut off the air vent, stayed around for a few hours and if the pressure increased slightly then vent again.
I spent many years running and maintaining large industrial boilers and various pressure vessels and carried out many pressure tests for leakages, some of these vessels had auto vents but in all cases once all the air was expelled then the auto vents were shut until the pressure test was completed.




Double post.(above, mine)

How long do you think they get at each job? They are probably limited to say an hour per job then may have to travel inbetween.

 

[Cazza]

I was told they get two hour slots

 

[Riley]

But I think the point is that not all jobs take two hours and anyone would be naive to think otherwise. That’s not a stab at you cazza im just saying. The expectation and demand on these engineers is sometimes unrealistic

 

[Millsy 82]

I was told they get two hour slots

You will get a 2 hour slot they will have to drive from the last job in that 2 hours if they hit traffic that could affect their time on site.

 

[Cazza]

Yes this is true and must affect their ability to be thorough. The crazy thing is because of their system of trying to save time on visits and repeat visits end up actually spending more time and money in the long run. If they had spent more time diagnosing and finding the isolation valve leak they wouldn't have replaced a heat exchanger! Perhaps Bosch should allow their engineers more time on a job (a stitch in time saves nine). I did find though all the Bosch men that arrived in pairs spent a lot of the time chatting between themselves about personal stuff, rather than fully concentrating on the job.

 

[Millsy 82]

When my dad was in hospital the nurses talked about their holidays to each other, when I go to a shop all the staff chat to each other about personal stuff. Everybody speaks about personal stuff.

I charge a fixed price for diagnosis because on average I spend about 20 minutes on breakdowns but sometimes a leak is extremely difficult to find.

 

[John.g]

If you suspected a boiler leak then with the apparent view that isolation valves don't hold, its obviously going to take longer than 20 minutes if you have to start blanking off.

 

[Cazza]

I've been in hospital before and seen patients wanting nurse attention ignored because nurses were too busy chatting. But yes of course colleagues will chat to one another and they should, what I meant was they didn't seem that motivated to fully diagnose the pressure loss. I think the ideas given in this thread says the Bosch men could have done more, things like test the isolation valves for leaking or block the airvent and see if there was a pressure rise. But they just seemed to want to do the bare minimum as quickly as possible, not to come back and move onto the next client. Even shouting at me almost that they can't come out again and saying I could have my money back, rather than get to the bottom of the issue as they promised they would if the gauge showed a drop in pressure, which it did.

 

[sammathias]

If half of your radiators are 'turnt off' then how can you test for a pressure loss successful?

 

[Cazza]

Hi. I'm not an expert, I'm no plumber and don't understand why this would make a difference as there is still water sat in the pipes. All the radiator valves have been checked for leaks (about 5 times) and there aren't any. The pressure loss test carried out by Bosch with the large gauges was on a (so say) isolated boiler and also on the radiator system at the same time. So at least it shouldn't have made any difference to the boiler test?

 

[John.g]

No it shouldn't but with "proper" isolation and two pressure gauges it should differentiate between the two systems, with both gauges falling together it certainly points to isolation valve(s) passing but doesn't tell which system is leaking.

 

[Riley]

This to and fro is kind of going in circles. If the OP gets nowhere with WB following this latest fix and contacting CEO then they will need to enlist an independent. Simplest option would be cut two ISO’s into the F & R temporarily if the ISO’s on the boiler are suspect. By the sound of it they’ve been replaced so I’d be dubious as to their failed functionality so soon . If you already have a primary filter on the return then you could isolate there.

 

[Cazza]

I'm going to leave it now for 2 weeks, to allow air to vent. If it drops down as low as 0.9 bar (from 1.3) then I will run an isolation test. If it still drops, then with it still isolated I will drain 250 ml from a radiator and watch the gauge to test the new isolation valves. If no further drop then I will assume its the boiler.
If the isolation valves are leaking I will assume it is the pipes (as my boiler sits higher than the radiators being on 2nd floor; so where the last isolation test showed both boiler and radiator leak I doubt a boiler leak would have shown up as a radiator leak).
The previous isolation test was done with a new right isolation valve, and an old left isolation valve. Now both are new. So I can't rule out the previous test had an isolation valve leak.
Thanks for all your thoughts everyone, I will put a note on my calendar to update this thread in a couple of weeks as so many have been interested. Feel free to comment further, but apologies if I don't reply as I need a break now from thinking about it ;-)

 

[sammathias]

Open 'all' the radiators...vent all the air out of radiators, when system is cold put pressure upto 2bar then isolate boiler....no drop over a day or 2 then boiler is fine, when isolation is turn back on and there's a drop then it's your rads or pipework.

 

[Cazza]

I will open all the radiators but I didn't want to put the pressure back up to 2 bar as by doing this aren't I adding air back into the boiler (which I would have just taken 2 weeks to let vent)? This would give a false pressure drop reading. I was just going to test it with 0.9 bar pressure.

 

[johnduffell]

around 50 litres is going to show a much bigger pressure loss with a cup full of water compared to a 10 rad system running at 100 litres

That's not true as water is incompressible for all practical purposes. The only bit that can expand when water is lost is the air in the expansion vessel.

I've had a system where the combi was in the loft in a bungalow, and bleeding a cup full of water out a radiator was enough to drop the pressure to nearly zero. So in my opinion, depending on the size of OPs system, yes a few drops from the isolation valves at the boiler is enough over a week, to drop 0.2bar of pressure.

That will have been a specific case where the expansion vessel no longer had any water in it. At the moment when the last water leaves the ev, the ev is full of air, so the air pressure has no effect on the system. This means the pressure on the boiler is the static head of water above the boiler. Which would be practically zero if the boiler is at the top of the system.

If the air in the ev was unconstrained, the pressure would carry on dropping smoothly.
Hope that is useful, even though irrelevant to the op.

 

[John.g]

I will open all the radiators but I didn't want to put the pressure back up to 2 bar as by doing this aren't I adding air back into the boiler (which I would have just taken 2 weeks to let vent)? This would give a false pressure drop reading. I was just going to test it with 0.9 bar pressure.

Just to be sure that we are talking about the same thing, pre pressure is the pressure at the air end of the E.vessel when its unconnected at the other (water) end, the filling (or test) pressure in your case is the pressure as shown at the boiler panel, you say you have a pre pressure of 1 bar, so if you just pressurised the system until exactly 1 bar then you will have no water (reserve) whatsoever in the E.vessel and theoretically if you drained a eggcup full of water from the system then that pressure will fall to 0, so how are you proposing to test the boiler at 0.9 bar?.
As stated above, assuming a prepressure of 1bar, a filling pressure of 2 bar will give you 2.67 litres of water (reserve) in the E.vessel, you will have 2.18 litres remaining when/if pressure falls to 1.75bar, 1.6 lires @ 1.5bar, 0.89 litre @ 1.25bar and 0 litres @ =or< 1.0 bar.

 

[Cazza]

Thanks John. I thought a Bosch guy said to me the gauge on the front of the boiler is showing you the water pressure, that the 1 bar pressure of air in the expansion vessel you can only measure with a meter connected to the expansion vessel. So I was thinking the two are separate and the gauge just measured the water sat in the heat exchanger part of the boiler. If I add water to the system until its 2 bar then I am adding air into the heat exchanger as well as water which will auto air vent and drop the pressure. I thought water only goes into the expansion vessel as the heat exchanger heats and expands the water, giving it somewhere to go.

 

[John.g]

The E.vessel contains a rubber "bladder" (called a diaphragm) like a heavy duty baloon, this is pumped up with air to whatever pressure is required, ie 0.5 bar to 1.0 bar depending on the E.vessel duty. The diaphragm will then be resting hard up against the opposite end of the E.vessel where the water connection is attached so in this state will contain 8 litres of air or whatever its capacity is.
You then open the filling valve and no water will be admitted to the E.vessel until the water side pressure is > than the prepressure, in your case (if it has been pumped up properly) 1 bar, the E.vessel will contain a certain amount of water based on this differential pressure and will compress the air on the opposite side of the bladder. Again in your case a 8 litre E.vessel with 1 bar prepressure and 2 bar filling pressure will contain 2.67 litres of water. As the boiler/system water heats up then the expanded water will be forced into the E.vessel and add to the existing 2.67 litres and the E.vessel (+boiler) pressure will rise further. There is no mixing of water and air in the E.vessel.

 

[Cazza]

Thanks for your reply John. I am still not sure what the gauge on the combi boiler is showing me exactly. Is it just the water pressure or boiler pressure (i.e. air in the expansion vessel plus the water pressure in heat exchanger and expansion vessel) ? Or is it just measuring the expansion vessel pressure water ?

 

[johnduffell]

Just to pick up where the other John left off, under normal working conditions the two will be identical. It's only setting the initial charge that it needs to be only air in there. Once your charge is set correctly and confirmed correct, you only need to worry about the overall system pressure.
The guage measures the water pressure though, hence when when the ev becomes empty it no longer reads the air pressure.

 

[Cazza]

So if the boiler gauge is only reading the water pressure and I'm doing an isolation test with the boiler off (so no water going into the ev) then I should be able to start the test with 0.9 bar water pressure

 

[Riley]

I am not being rude but this is getting needlessly complicated

 

[Cazza]

Can you not just answer my question Riley?

 

[Riley]

Yes I’ll happily give more free advice!! Seriously, remember people are giving their time here for nothing. Again I’m not being rude Cazza, this thread has leapt from one extreme to the other originally you were complaining about WB, then you were going to contact the CEO, which were it me I’d still do irrespective of whether they’ve fixed it this time or not because of appalling customer service. Now we have got to the fine tuning of a boiler which you can’t do and the chaps giving advice above should really know better as you can’t take your boiler case off as you’re not Gas Safe.

Quite simply you either have a leak or not. Leave it the two weeks you said you would and see if it’s lost pressure. As said above let the system be completely cold before setting your pressure then just monitor it. You haven't even given this latest fix a chance yet. If they have replaced the two valves on the boiler then I’d be very surprised if they are not shutting off properly for potential future isolation tests.

Ultimately this comes down to what you sort with WB as I still feel that the buck stops with them. But if they wash their hands of it then enlist a local recommended engineer to come in and look for you and build a rapport don’t go on the attack with him. Sometimes finding a leak requires a couple of visits, it’s not always incompetence

 

[Cazza]

I know people are giving their time and I thanked everyone in one of my last posts and said I wanted to leave it 2 weeks. But then John came back saying it won't work. So now I am just trying to understand why that is. Thats all Riley! No need to patronise me or say I am ungrateful. I take offense you are saying to me not to go on the attack with a new engineer. I was extremely patient with all the 8 Bosch visits to my property always being polite and offering many cups of coffee and tea. Never once raised my voice or criticised. Yet I do feel I was unfairly treated by them.
Like I keep saying I can't top it up to 2 bar because that is putting AIR into the boiler which will give a false reading.
I thank again all the people trying to help me on this forum and its a shame some people's motive for helping seems to belittle and put others down (as often happens on internet forums just to make themselves feel better because they are having a bad day)

 

[John.g]

So if the boiler gauge is only reading the water pressure and I'm doing an isolation test with the boiler off (so no water going into the ev) then I should be able to start the test with 0.9 bar water pressure

So if the boiler gauge is only reading the water pressure and I'm doing an isolation test with the boiler off (so no water going into the ev) then I should be able to start the test with 0.9 bar water pressure

So if the boiler gauge is only reading the water pressure and I'm doing an isolation test with the boiler off (so no water going into the ev) then I should be able to start the test with 0.9 bar water pressure

Because water is incompressible then if you do the test at 0.9bar, the pressure should drop to 0 as soon as the tiniest amount of water leaks or is released. In practice, there is all ways some small amounts of air entrained in the water so this will act as a sort of E.vessel in itself, the point is that you will have no idea what amount of air is entrained so the pressure may drop to zero very rapidly or very slowly. That is why it is advisable to pressurise higher than the pre pressure as air is compressible and you can get a accurate feel (time wise) for any drop in pressure as the amount of water released will be exactly the same each time.
OK, if you pressurise only to 0.9 bar and you then have NO subsequent fall off in pressure then it would be hard to argue that there is any leak present.

 

[Riley]

Right I’m out. A leak is a leak. There’s no more benefit putting 2 bar in as there is 1.5 it’s maths. If it drops you have a leak. You have an automatic air vent on the boiler to deal with air. If the Ev is set correctly then you shouldn’t have issue there either.

Just FYI I wasn’t patronising. It’s very easy to vent into the guy coming in to fix someone else’s cock up. Was just giving you a heads up. But as you seem to think it’s now our fault you can’t get it sorted then I wish you luck

 

[Cazza]

Riley I never said it was anyone's fault on this forum.

Many thanks for explaining John. The pressure gauge hasn't dropped from 1.3 bar since Saturday morning (even with a firm flick). So i'm hoping replacement of the leaking valves has done the trick.

 

[SimonG]

Is this still ongoing?

I'm sure that a visit from a competent engineer would have had you sorted.

 

[sammathias]

How is topping up pressure to two bar adding a load of air into system. Please explain?

 

[Cazza]

UPDATE: The boiler gauge has still lost pressure from 1.5 bar to 1.2 bar within exactly a week. So I've decided to write to Martyn Bridges, top technical person at Worcester Bosch with all that's happened. I will let you know IF I hear back.

 

[John.g]

Not sure if this is with the boiler isolated or not for the week?. One way or the other the boiler or boiler/system is after losing almost 0.9 litres of water or else air is still being released through the boiler auto air vent.

 

[Cazza]

Hi. No not isolated, just normal. I've started an isolation test this morning. Not adding anymore water to it (1.2 bar start off) in case of adding back in any air. My gut feeling is it's not auto air venting, especially as i've got new lot of inhibitor in the system. The two new isolation valves don't appear to be leaking, so I think they fixed that. I have seen on google that if the pump setting is too high this can cause a pressure loss (something to do with cavitation don't really understand) so maybe its that I don't know if Worcester checked this.
It will be interesting to see, with the two new isolation valves, if there is any pressure loss whilst boiler isolated. But I wrote off to Marytn Bridges because like Bosch themselves told me it shouldn't be me still worrying about it, after Bosch found a pressure drop on the boiler gauge.

 

[sammathias]

Blah blah. Going around in circles and yet still don't listen to a word suggested.

 

[Cazza]

I've taken on board what everyone has said. Well I ran the isolation test for the last 24 hours and it dropped 0.15 bar at least. I've just taken 200 ml out of a radiator with it still isolated and it doesn't drop on the gauge. This is telling me its definately the boiler losing pressure. Whether that is because of air still venting 9 days later I don't know. But my guess is its still just going to keep on dropping as that's what its always done.
I wrote to Martyn Bridges but had an out of office reply that he is not back for 2.5 weeks. Just my luck.
I guess I will have to get out my own engineer and send the bill to Bosch because if there is a leak they've caused it?

 

[Cazza]

I've reversed the isolation test and i'm going to carry on giving it the obligatory two weeks, so if after the 18th April it keeps on dropping pressure then i'll know for sure its not just air venting and can update Mr Bridges with the information.

 

[Riley]

I've taken on board what everyone has said. Well I ran the isolation test for the last 24 hours and it dropped 0.15 bar at least. I've just taken 200 ml out of a radiator with it still isolated and it doesn't drop on the gauge. This is telling me its definately the boiler losing pressure. Whether that is because of air still venting 9 days later I don't know. But my guess is its still just going to keep on dropping as that's what its always done.
I wrote to Martyn Bridges but had an out of office reply that he is not back for 2.5 weeks. Just my luck.
I guess I will have to get out my own engineer and send the bill to Bosch because if there is a leak they've caused it?

I realise your frustration Cazza but seriously how have they caused it?? No one will set out to purposely cause an issue with your boiler. You do realise that there is a good chance that your boiler may just have had more than one issue. I went out to a WB the other day and there were three separate leaks on it. The third was an absolute nightmare to locate and I only found it because of a drip passing through the beam of my torch. Don’t be so aggressive and I’m sure you will get there. If you don’t then keep on at WB but I would not lead with them causing leaks as they will just not take you seriously. Be factual

 

[Cazza]

Well my conclusion is in the last 6 days it has not dropped (hardly anything anyway). Its now been over 2 weeks since WB last came. I've not had the heating on much. But if there was a leak it would have shown even switched off i'm guessing. When I put the heating on next winter if it starts losing pressure again then all I can think it is the pump setting is too high and causing air venting (would explain the vibration noise I get as well). So when I get it serviced next year I will ask them to check this and slow it down a bit. So i've no need to go back to WB. But I am glad I persevered with them and got them back out because on their very last visit they did fix the isolation valve leaks which needed to be done. I don't think my last post was aggressive, I even had a question mark as to question if they caused the leak. Anyway no point in arguing.
Thanks everyone for your thoughts, just glad I can leave it be now.