For a few years now the industry has put up with the expansion vessel & it's very short life, it's time for a change - time for something else that's more reliable.
Why are all expansion vessels so cr#p!!
- Thread starter Richardthe3rd
- Start date
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I don't know why Dickie is saying that!
Most boilers with built in expansion vessels ( EXV ) are never checked for 5 to 10 years and yet still continue to function correctly.
A conscientious engineer will test and repressurise at the annual service.
But perhaps that's only 15% of engineers doing annual servicing? The standard British Gas "safety check" only measures flue gas composition and does not look at the EXV.
But then to make things worst many home owners don't get their boilers serviced annually.
Tony
Most boilers with built in expansion vessels ( EXV ) are never checked for 5 to 10 years and yet still continue to function correctly.
A conscientious engineer will test and repressurise at the annual service.
But perhaps that's only 15% of engineers doing annual servicing? The standard British Gas "safety check" only measures flue gas composition and does not look at the EXV.
But then to make things worst many home owners don't get their boilers serviced annually.
Tony
Tony, where did you get 15% from ?
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That is my own assessment. Probably less than 15% really.
The CC members are not typical RGIs and I would hope that most will check EXVs on a service.
Unfortunately from my experience is that BG hardly ever check EXVs and many are not very good when there is a problem with them.
A friend had to pay me to sort her's out even when she had BG cover. A few weeks ago she had further problems and needed two BG visits and for the second I had to give her the instructions so she could tell them what was needed.
Tony
The CC members are not typical RGIs and I would hope that most will check EXVs on a service.
Unfortunately from my experience is that BG hardly ever check EXVs and many are not very good when there is a problem with them.
A friend had to pay me to sort her's out even when she had BG cover. A few weeks ago she had further problems and needed two BG visits and for the second I had to give her the instructions so she could tell them what was needed.
Tony
Ah, your annual supply of condoms Danny Boy. Please pass on my regards to your wife's sister.
Not my experience Tony. All expansion vessels are of very poor quality.
Ah, your annual supply of condoms Danny Boy. Please pass on my regards to your wife's sister.
And how would you know about SIL Dicky boy?
. You sneaky lurker you They look a little small in width to me!
The only problem EXVs that I have become aware of is with many Worcester boilers, even very new ones, that either dont come correctly charged ( lets face it virtually no installers bother checking them ) or leak air after a very few years.
Tony
The only problem EXVs that I have become aware of is with many Worcester boilers, even very new ones, that either dont come correctly charged ( lets face it virtually no installers bother checking them ) or leak air after a very few years.
Tony
Zilmet vessels have been awful, 2 years is a good age for one.
All the wholesalers stock them, because apparently most of us in the trade 'just want whatever's cheapest'.
Vaillant ecoTECs have Zilmet*, and if you work on these nothing more needs to be said.
We use the Altecnic Reflex, which is a German vessel. However, I have to order these in from our merchant because they only stock...Zilmet!
*noticed their latest replacements are a slightly different shape so I assume they've seen the light and changed supplier.
All the wholesalers stock them, because apparently most of us in the trade 'just want whatever's cheapest'.
Vaillant ecoTECs have Zilmet*, and if you work on these nothing more needs to be said.
We use the Altecnic Reflex, which is a German vessel. However, I have to order these in from our merchant because they only stock...Zilmet!
*noticed their latest replacements are a slightly different shape so I assume they've seen the light and changed supplier.
The main problem has to be that they are too small for the systems they serve. Also, those fitted in boilers very often get too hot. Where a reasonably sized vessel is sited on the system, I find them very reliable. As regards testing, many gas boilers, and some oil, are impossible without dismantling the boiler. When they fail, the only option is to take the boiler off the wall, or put another vessel elsewhere, as recommended by Ravenheat for many of their range of boilers.
The main reason is that they don't get checked each year and when installers claim to do so they aren't dropping the pressure and doing it properly.
I've had to replace very few vessels over the years but I constantly find vessels very low on pressure despite the service log being filled in the year before...and you get the usual from the customer when you get the pump out...."that's never been done before"
I'd say 90% of so called boiler services do not have the vessel checked....there's plenty of MI that forget to mention a vessel check in the servicing.
How many installers check the vessel at installation time? I used to find plenty out the box with low pressure.
The Reflex vessels are a trade name of Winkelmann and Pannhoff....all the older Vaillants used W&P vessels and they can last 25 years or more. Perhaps W&P are one of the few genuine German companies that still have quality to their name....I guess far too expensive for Vaillant these days.
I've had to replace very few vessels over the years but I constantly find vessels very low on pressure despite the service log being filled in the year before...and you get the usual from the customer when you get the pump out...."that's never been done before"
I'd say 90% of so called boiler services do not have the vessel checked....there's plenty of MI that forget to mention a vessel check in the servicing.
How many installers check the vessel at installation time? I used to find plenty out the box with low pressure.
The Reflex vessels are a trade name of Winkelmann and Pannhoff....all the older Vaillants used W&P vessels and they can last 25 years or more. Perhaps W&P are one of the few genuine German companies that still have quality to their name....I guess far too expensive for Vaillant these days.
I have also found new boilers with very low pressure and sometimes wonder if thats to encourage installers to check and increase the pressure.
One of my easiest jobs was when a customer got BG to replace the failed EXV on an older Ideal. They fitted an external one but it did not absorb the expansion at all and so the landlord called me to sort it out.
The fault was so simple! They had been supplied at 3 bar air pressure and the BG guy had not bothered to check the pressure when he fitted it.
Tony
One of my easiest jobs was when a customer got BG to replace the failed EXV on an older Ideal. They fitted an external one but it did not absorb the expansion at all and so the landlord called me to sort it out.
The fault was so simple! They had been supplied at 3 bar air pressure and the BG guy had not bothered to check the pressure when he fitted it.
Tony
At a show once I was chatting to the MD of a vessel manufacturer and getting on well just chewing the fat.
I then said I suspect vessels are not as good as they used to be and don't last the life of the appliance.
His face froze and said "don't give me that, we've made vessels for years, it isn't rocket science, it's two sheets of metal, a thick rubber diaphram and a shraeder valve. If a vessel fails withiht the lifetime of the appliance it's usually too small for the system or contaminated water. We get them back and open them up"
Maybe you'd expect a manufacturer to say that but it isn't rocket science and 6,8,10 litre vessels are put on 35KW boilers maybe handling up to 20-30 rads. An 8 litre vessle will handle around 70 litres of system volume; when was the last time most guys worked out, even guessed the system volume?
I then said I suspect vessels are not as good as they used to be and don't last the life of the appliance.
His face froze and said "don't give me that, we've made vessels for years, it isn't rocket science, it's two sheets of metal, a thick rubber diaphram and a shraeder valve. If a vessel fails withiht the lifetime of the appliance it's usually too small for the system or contaminated water. We get them back and open them up"
Maybe you'd expect a manufacturer to say that but it isn't rocket science and 6,8,10 litre vessels are put on 35KW boilers maybe handling up to 20-30 rads. An 8 litre vessle will handle around 70 litres of system volume; when was the last time most guys worked out, even guessed the system volume?
This may help the hard of thinking;
https://www.flamcogroup.com/files/calculationtools/ins_exp_flexcon_calculation.pdf
https://www.flamcogroup.com/files/calculationtools/ins_exp_flexcon_calculation.pdf
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