recommendation And advice are welcome.

[Old Account]

hi lads,

I just went today to a customer which wants me to convert his back boiler and hot water cylinder to a sealed system. He wants me to install a Vaillant 938 with 11 rads ( most of them are large 1400x600 ) and future 2 bathrooms.
He is worried that the pressure will drop significantly but I assured him due to my experience and based on Vaillant that it won’t happen and that the 938 will be fine. He is upgrading the mains water supply to 32 mdpe.
Will this type of boiler enough for future zoning? He is planning on splitting the zones in to 3 zones which are ufh downstairs, upstairs rads, downstairs rads.

However, at the moment his last radiator in the bathroom upstairs is only working half way ( vertical radiator). The difference between the F&E tank and the vertical Rad is about 10-20cm at max. Is that the problem why it doesn’t work in full?

Thank you for your help

 

[Best]

Should still work.
System dirty, or not balanced, or not piped with big enough pipes, or pump not up to job?

 

[Scott_D]

I would go for an unvented cylinder

 

[Best]

I just realised there are several questions

 

[Old Account]

Should still work.
System dirty, or not balanced, or not piped with big enough pipes, or pump not up to job?

Tha k you very much Gary. To be fair, I believe you are so right about dirty system as it never has been serviced and flushed in the last 50 years. The next thing is the central heating pipes from the boiler are starting in 22mm but after 2 m it reduces to 15mm.at the moment they only have downstairs rads and one added upstairs bathroom. The rest of the property has those old type gas heaters in the wall ( never seen them before ). Surely not balanced either. I was thinking air could be trapped too.

 

[Old Account]

I would go for an unvented cylinder

What’s your experience with storage combi boilers? Have you fitted some before to multiple bathrooms?

 

[Harvest Fields]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

 

[Old Account]

Because the mounted 20-liter storage behind the initial boiler makes as much as a conventional 70-liter storage cylinder therefore I’m thinking it should be well enough

 

[Old Account]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

Really? What problem are you facing mate?

 

[Harvest Fields]

Because the mounted 20-liter storage behind the initial boiler makes as much as a conventional 70-liter storage cylinder therefore I’m thinking it should be well enough

I believe you to be miss informed here mate.

 

[Harvest Fields]

Really? What problem are you facing mate?

Hot water cutting out with no fault code or error message.

 

[Old Account]

I believe you to be miss informed here mate.

I spoke to Vaillant a few times back in Germany and we have the same boiler but with less kw. If you scroll down you will see in the description there is clearly written what the boiler is capable off.
Wandheizgerät ecoTEC plus VCI - Produktinfos | Vaillant

However, what size of property is it? Have you spoken to Vaillant yet? For how long is that going on for and is it since the beginning?

 

[Harvest Fields]

I spoke to Vaillant a few times back in Germany and we have the same boiler but with less kw. If you scroll down you will see in the description there is clearly written what the boiler is capable off.
Wandheizgerät ecoTEC plus VCI - Produktinfos | Vaillant

But that isn’t what you said mate. You referenced to the storage vessels. They are not 20 litres. They are 15 between them. The 20ltrs refers to the possible flow rate.

 

[Harvest Fields]

Boiler 3 years old. 4 bed 1 bath 1 shower. Yes to Vaillant who can only offer possibilities and about 6 months.

 

[Old Account]

Boiler 3 years old. 4 bed 1 bath 1 shower. Yes to Vaillant who can only offer possibilities and about 6 months.

But the boiler should be under a certain warranty and therefore Vaillant could come out to access the job.

 

[Harvest Fields]

But the boiler should be under a certain warranty and therefore Vaillant could come out to access the job.

To do what?? They have said unless there is a fault occuring the job is chargeable and mg customers first point of call should always be me.

 

[Old Account]

To do what?? They have said unless there is a fault occuring the job is chargeable and mg customers first point of call should always be me.

That’s weird with being charged though. If you already have paid for warranty that should be all covered. There is clearly an issue with the boiler ... have you checked the pump at the back for the cylinder ? That’s one of the faults which is quite common. It’s a little bit awkward to get to but you should be able to check that.

 

[Old Account]

I believe it’s called shunt pump

 

[Scott_D]

What’s your experience with storage combi boilers? Have you fitted some before to multiple bathrooms?

No but once the 20 litres of stored hot water has gone it’s just a Vaillant 838 Combi so about 15 lpm of hot water available

 

[Harvest Fields]

When I am there it all looks like it is doing what it is supposed to mate. Only happens about once every 2 weeks

 

[Old Account]

No but once the 20 litres of stored hot water has gone it’s just a Vaillant 838 Combi so about 15 lpm of hot water available

The cylinder won’t run empty. As explained earlier it’s capable of making as much as a conventional cylinder.

 

[Old Account]

When I am there it all looks like it is doing what it is supposed to mate. Only happens about once every 2 weeks

Just have a look next time harvest. It’s a common fault that the shump pump has an intermittent fault.

 

[Last Plumber]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

What's the issue? (curiosity).
EDIT:
Sorry just read the thread!

 

[Last Plumber]

Does it cut out or do they just struggle to get DHW?

 

[Harvest Fields]

The cylinder won’t run empty. As explained earlier it’s capable of making as much as a conventional cylinder.

No it isn’t mate. Once the 15ltr store is empty it shifts into combi mode

 

[Harvest Fields]

Does it cut out or do they just struggle to get DHW?

Runs cold then they have to turn the tap off and back on again. The only thing I can think of is the flow switch isn’t recognising the demand from store to combi

 

[Last Plumber]

Runs cold then they have to turn the tap off and back on again. The only thing I can think of is the flow switch isn’t recognising the demand from store to combi

Do they have any mixer valves?
Showers, TMV's etc?
Could it be a passing valve?
You might have ruled that out already but I thought I'd mention it as I came across a similar issue the other week.

 

[Harvest Fields]

Do they have any mixer valves?
Showers, TMV's etc?
Could it be a passing valve?
You might have ruled that out already but I thought I'd mention it as I came across a similar issue the other week.

All of them. And isolated each 1 by one. All brand new as I put them in. What was your issue.

 

[Last Plumber]

All of them. And isolated each 1 by one. All brand new as I put them in. What was your issue.

Did you try turning the cold to the Boiler off underneath and running a hot tap? there should be nothing flowing as you will undoubtedly know.

My issue was that the Hot water was running but more often than not tepid. Occasionally it was hot and OK.

The Boiler appeared to be running OK and doing what it should do and at first I suspected other things. Turned out to be a passing valve. Not always the same though due to fluctuations in pressure.

 

[Harvest Fields]

It is a 938 mate so with no taps on the stores still empty.

 

[Last Plumber]

It is a 938 mate so with no taps on the stores still empty.

What do you mean?
I meant that if you turned the water off to the Boiler and water still runs from a hot tap, it must be getting in elsewhere. If that is happening, when you run a hot tap with the Boiler working, it will mix and cool the DHW. It can also out balance the hot totally and allow only cold to run, depending on the system. There will always be slightly more resistance through the Boiler than direct.

If we are talking at cross purposes, let me know?

 

[Harvest Fields]

I miss understood. When the boiler cold is isolated the 2 x storage vessels empty then the water stops is what I meant. Sorry.

 

[Last Plumber]

I miss understood. When the boiler cold is isolated the 2 x storage vessels empty then the water stops is what I meant. Sorry.

Oh I see. If the flow stops then no you're right, it won't be a passing valve lol.

 

[Scott_D]

The cylinder won’t run empty. As explained earlier it’s capable of making as much as a conventional cylinder.

Do you mean with a blending valve it’s the equivalent of a conventional tank?
It won’t run empty but once the 20 litres is used it just works as an 838 then reheats the cylinder when it gets chance

 

[sammathias]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

Don't talk dirty about our beloved vaillants.

What's wrong with it?

 

[Harvest Fields]

Don't talk dirty about our beloved vaillants.

What's wrong with it?

It’s all detailed in the previous posts mate. I would never bad mouth Vaillant’s. They are all I fit normally.

 

[Old Account]

Do you mean with a blending valve it’s the equivalent of a conventional tank?
It won’t run empty but once the 20 litres is used it just works as an 838 then reheats the cylinder when it gets chance

That’s correct I may misunderstood you scott. Yes it would be equivalent to a conventional tank of 70l

 

[Harvest Fields]

That’s correct I may misunderstood you scott. Yes it would be equivalent to a conventional tank of 70l

Am I missing something here?

 

[Last Plumber]

Am I missing something here?

Lol.

 

[Harvest Fields]

The store on a 938 is 15ltrs. How will that be like a 70ltr tank?

 

[Scott_D]

The store on a 938 is 15ltrs. How will that be like a 70ltr tank?

You just add 55 litres of cold 😀

 

[Harvest Fields]

I am just putting this out there before I completely get confused.

The storage on a 938 is 7.5 ltrs a vessel, so 15ltrs total, producing upto 20ltrs/m. Once the vessel is cold it switches to a combi @ approx 16ltrs/m.

 

[Last Plumber]

I am just putting this out there before I completely get confused.

The storage on a 938 is 7.5 ltrs a vessel, so 15ltrs total, producing upto 20ltrs/m. Once the vessel is cold it switches to a combi @ approx 16ltrs/m.

Yes.

The combi is an 838. It will only perform with the same ability as the 838 (because that's what it is), but with the additional pre heated (secondary water) store.

In theory as you draw off water the store is being replenished and therefore there is a delay in time before you get to be using purely the combi's performance.

There are figures about that state the performance being the same as an unvented cylinder but I personally tend to ignore the magic figures and see it for what it is..... A combi with a bonus!

My opinion.

 

[Harvest Fields]

Cheers @Last Plumber I thought that I was going mental

 

[Last Plumber]

The next thing is the central heating pipes from the boiler are starting in 22mm but after 2 m it reduces to 15mm

Those 15mm pipes will only carry 22000-25000 Btu's comfortably in my experience. At a push you may get 30000 but you will be lucky. It will present problems and noise is one of them.

 

[Last Plumber]

15mm.at the moment they only have downstairs rads and one added upstairs bathroom

What outputs?
You need to add them up and work it out.

 

[Last Plumber]

( most of them are large 1400x600 )

What kind? P1, P+, K1 or K2?
It all makes a difference especially if it's off 15mm

 

[Last Plumber]

Combi's are fine and even large ones like the 938 and they do perform well whilst the store is there but they are still only combi's once it has gone.
In houses with more than one bath / shower room and families, I would always advise having a modern unvented cylinder. The reheat times are very good as you all know and the back up of an immersion heater is there too. If sized, fed and piped correctly, you can run what you like without issue.

 

[Old Account]

Am I missing something here?

Yeah I did a mistake in terms of saying it would not run empty obviously it does that’s the writing mistake I made.

 

[Old Account]

The store on a 938 is 15ltrs. How will that be like a 70ltr tank?

Mate, just have read online... it’s german I know but I don’t know how else I can explain that. It’s clearly written that’s equivalent to a 70liters cylinder

 

[Harvest Fields]

Yeah I did a mistake in terms of saying it would not run empty obviously it does that’s the writing mistake I made.

You also said the store was 20 ltrs mate. Anyway it doesn’t matter I still wouldn’t fit one.

 

[Old Account]

You also said the store was 20 ltrs mate. Anyway it doesn’t matter I still wouldn’t fit one.

It’s fine, I made a mistake which means I am not flawless. However attached I will show you what you could perhaps translate. Perhaps it makes sense to you. I don’t want to argue just stating the fact which is dated by me but by Vaillant itself.

 

[Harvest Fields]

It’s fine, I made a mistake which means I am not flawless. However attached I will show you what you could perhaps translate. Perhaps it makes sense to you. I don’t want to argue just stating the fact which is dated by me but by Vaillant itself.

View attachment 36832

I understand Ron but that is Germany and this is England and if I’m honest I don’t care about Germany. I do not live or work in Germany. I live and work in England where our regs and boiler spec are different and as far as Vaillant have told me the stores on an 937 are 7.5ltrs each and once cold all you have left is an 837 combi boiler.

 

[Old Account]

I understand Ron but that is Germany and this is England and if I’m honest I don’t care about Germany. I do not live or work in Germany. I live and work in England where our regs and boiler spec are different and as far as Vaillant have told me the stores on an 937 are 7.5ltrs each and once cold all you have left is an 837 combi boiler.

That’s fine, I appreciate your opinion. You can trust me that this boiler as well as the green IQ, ecotec plus 825 are equivalent to german boilers. I do understand what you’re saying and agree that is slightly different in terms water pressure etc. Perhaps that would make a huge different in many cases. If I am honest I would fit an ecovit or ecoCOMPACT but unfortunately it doesn’t exist here in uk. Done take me in the wrong way mate

 

[Harvest Fields]

That’s fine, I appreciate your opinion. You can trust me that this boiler as well as the green IQ, ecotec plus 825 are equivalent to german boilers. I do understand what you’re saying and agree that is slightly different in terms water pressure etc. Perhaps that would make a huge different in many cases. If I am honest I would fit an ecovit or ecoCOMPACT but unfortunately it doesn’t exist here in uk. Done take me in the wrong way mate

I haven’t mate. I just go off what Vaillant tell me thats all.

 

[king of pipes]

Not my boiler of choice for that job Ron you need to be ripping out all that pipework there will be so much magnatite in there it will wreck the valliant even if you fit a mag filter, and I would at least get the rads off and flush them through outside if possible ideally replace them to and all the valves you do seem to get em bud. Good luck with it kop

 

[Harvest Fields]

That’s fine, I appreciate your opinion. You can trust me that this boiler as well as the green IQ, ecotec plus 825 are equivalent to german boilers. I do understand what you’re saying and agree that is slightly different in terms water pressure etc. Perhaps that would make a huge different in many cases. If I am honest I would fit an ecovit or ecoCOMPACT but unfortunately it doesn’t exist here in uk. Done take me in the wrong way mate

More to the point mate. You shouldn’t be using German boiler data to fit boilers in England anyway. One has nothing to do with the other.

 

[Old Account]

Not my boiler of choice for that job Ron you need to be ripping out all that pipework there will be so much magnatite in there it will wreck the valliant even if you fit a mag filter, and I would at least get the rads off and flush them through outside if possible ideally replace them to and all the valves you do seem to get em bud. Good luck with it kop

You KOP, you advise in the same way as I do but customer apparently spent his whole money for the house and has to safe up for a new refurbishment. I just told him yesterday that he needs upgrading all radiators as this boiler is in there for 50 years. Upstairs there is no central heating at all it’s kind of old gas fires for each room but they are installed in the wall never seen something like this before. Furthermore the central heating supply downstairs which has about 5 big radiators including the added one upstairs in the bathroom have all 15mm supply. From the boiler it goes in 22mm for about 1.5m the rest all in 15mm. He even wanted me to fit more radiator los upstairs but it will not work without me installing a new supply in 22mm. All windows are either 1.5 or 2m long and require a minimum of double panel due to the high ceilings and room sizes. I did tell him that about the pipes being too dirty for a new boiler and a flush would not help to get rid of all.

As you k ow the customer k ones always better than you do.

Thank you for your kind advise it’s definitely appreciated

 

[Old Account]

More to the point mate. You shouldn’t be using German boiler data to fit boilers in England anyway. One has nothing to do with the other.

It’s equivalent so there is no difference in data. But that’s ok I do not want to keep arguing with you.

 

[Harvest Fields]

It’s equivalent so there is no difference in data. But that’s ok I do not want to keep arguing with you.

If the German 938 has a 20 Ltr store then it is not equivalent! You just need to admit that the uk version has a 15 ltr store and I will leave you alone mate.

 

[Harvest Fields]

@Matchless.plumb as I know you have seen my message but not replied. I am just going to leave this picture here. Please stop misinforming customers by using data that is not of any relevance in the uk. Start using the correct Vaillant data book. If you do not have one call the rep they will send you one.

 

[Old Account]

@Matchless.plumb as I know you have seen my message but not replied. I am just going to leave this picture here. Please stop misinforming customers by using data that is not of any relevance in the uk. Start using the correct Vaillant data book. If you do not have one call the rep they will send you one.

View attachment 36834

I will get back to you shortly. I agree I have read your reply but due to my research I did not reply as i want to avoid MISINFORMING people. I will get to the bottom of it. If I am wrong I will apologise but I really doubt that these 2 boilers are not identical!

 

[Harvest Fields]

Research away mate. They may look identical and sound identical. But uk rules are much more lax than in Germany and that is probably why they are different.

 

[Old Account]

Research away mate. They may look identical and sound identical. But uk rules are much more lax than in Germany and that is probably why they are different.

You buy those boiler in separate packs right? Where does the cylinder come from, Remscheid- Germany ? Or Kent ?
Is there written VIH CL 20?

 

[Harvest Fields]

You buy those boiler in separate packs right? Where does the cylinder come from, Remscheid- Germany ? Or Kent ?

Wolseley or city Plumbing

 

[Old Account]

Wolseley or city Plumbing

Alright, but they come in separate boxes?

 

[Harvest Fields]

Alright, but they come in separate boxes?

Yes mate. But doesn’t change the fact that they are 7.5ltrs each in the uk

 

[Old Account]

Yes mate. But doesn’t change the fact that they are 7.5ltrs each in the uk

It makes a huge difference if your supplier gets them from Remscheid as these are 20liter storage and not 15. 3 months ago I installed a few which came from Remscheid and it has 20liters not 15.
If you see the description VIH CL 20 then you can be certain it’s twice a 10liter storage.

 

[Old Account]

I’m just going to leave this picture here for you

 

[Harvest Fields]

That is clearly a typo Ron. As you can see from the picture I have uploaded, the diagram is for the 15 ltr version. Also if you type the part number into any uk based search engine it only brings up the 15ltr vessels. Vaillant only sell the 15ltr version in the uk as far as I am aware. Vaillant uk only market it with 15ltr vessels. If your supplier is giving you 20ltr vessels he shouldn’t be, as it is not for the uk market and I am sure it will void the warranty.

 

[Old Account]

That is clearly a typo Ron. As you can see from the picture I have uploaded, the diagram is for the 15 ltr version. Also if you type the part number into any uk based search engine it only brings up the 15ltr vessels. Vaillant only sell the 15ltr version in the uk as far as I am aware. Vaillant uk only market it with 15ltr vessels. If your supplier is giving you 20ltr vessels he shouldn’t be, as it is not for the uk market and I am sure it will void the warranty.

View attachment 36847

That’s typo Ron 🙂 I spoke to Vaillant today and he has confirmed that they get those tanks from Kent and from Remscheid. Which means the once from Remscheid are 10 Liters each. I have not got a specific supplier I order in different local stores so I am sure it’s not not illegal for them to sell those type of storage tanks.

 

[Harvest Fields]

You can lead a horse to water but you cannot make it drink. You believe what you will mate. As it sounds like you are going to anyway. I also spoke to Vaillant and they told me that the 938 has a 15ltr store so I’m happy that I am right. Good luck in what ever you do.

 

[Old Account]

You can lead a horse to water but you cannot make it drink. You believe what you will mate. As it sounds like you are going to anyway. I also spoke to Vaillant and they told me that the 938 has a 15ltr store so I’m happy that I am right. Good luck in what ever you do.

No point of arguing here harvest. What’s the point ? I don’t mind you being right ... I’m not here to fight or proof that you are wrong. I will keep misinforming my customers and you keep installing the 15ltr storages 🙂 let’s put an end to this and talk about something else.

 

[Harvest Fields]

I would love to mate. But I do not work like that. Especially when I know I am right.

https://www.vaillant.co.uk/download...2015/0020209593-01-ecotec-plus-938-559182.pdf

Vaillant’s manufacturer’s instructions for the boiler.

Page 9 top right hand corner. 3.1
also page 61 Shift load cylinder capacity 15ltrs

 

[Old Account]

I would love to mate. But I do not work like that. Especially when I know I am right.

https://www.vaillant.co.uk/download...2015/0020209593-01-ecotec-plus-938-559182.pdf

Vaillant’s manufacturer’s instructions for the boiler.

Page 9 top right hand corner. 3.1
also page 61 Shift load cylinder capacity 15ltrs

View attachment 36849

How do you know how I work mate? I do not think that I am doing bad jobs nor do I think I am cutt8ng any corners, ripping anyone off or false Information are given. Next time, I will take a picture of the storage I am installing. I have seen the manual and have seen the figures. Trust me, my work ain’t bad otherwise I would not have any customers nor would I work only on recommendations. I take too much pride in my work. However, it is ok if you want to be right that’s fine with me mate really I don’t mind to be wrong as nobody is perfect.

 

[Harvest Fields]

Ron. I didn’t say that I knew how you worked. I also didn’t say that you was doing bad jobs or cutting corners or ripping people off. I did however ask you to stop using the wrong data sheets and to not miss inform customers. I say this as I wouldn’t want it coming back and biting you on the bottom later on, that’s all. I know I have upset you and I honestly didn’t mean to. I was just trying to prove my point.

 

[Old Account]

Ron. I didn’t say that I knew how you worked. I also didn’t say that you was doing bad jobs or cutting corners or ripping people off. I did however ask you to stop using the wrong data sheets and to not miss inform customers. I say this as I wouldn’t want it coming back and biting you on the bottom later on, that’s all. I know I have upset you and I honestly didn’t mean to. I was just trying to prove my point.

https://www.vaillant.co.uk/downloads/ecotec-plus-937-spare-parts-manual-261488.pdf

Clearly states for model vih vl 15 s / 10liter each vessel ... that’s sold in uk. You can use the part number 0020039781 and you can get that online heating spares etc ...

 

[Old Account]

Ron. I didn’t say that I knew how you worked. I also didn’t say that you was doing bad jobs or cutting corners or ripping people off. I did however ask you to stop using the wrong data sheets and to not miss inform customers. I say this as I wouldn’t want it coming back and biting you on the bottom later on, that’s all. I know I have upset you and I honestly didn’t mean to. I was just trying to prove my point.

You really did not upset me.. I like discussing matters which is totally normal. I just don’t believe I’m so wrong ... I can see I can get the storage on English markets with the part number which indicates that you misunderstands the vih cl 15s that’s just the name of the boiler. If you type in the part numbers you can see that the storage comes up with 10 litres each. A lot of Vaillant
Engineers haven’t got a clue if you talk with the, on the phone. Just 2 days ago I spoke with one guy and he wanted to tell me I would need 3 bar mains pressure and 20l flowrates to be able to install this boiler. I had to call a different guy and he told me it was total boll.... the point I want to make is that I strongly believe that it’s the same boiler like Germany with a slight difference in kw output. We have 20 and 26 which is well enough but here in uk is 38kw

 

[Harvest Fields]

https://www.vaillant.co.uk/downloads/ecotec-plus-937-spare-parts-manual-261488.pdf

Clearly states for model vih vl 15 s / 10liter each vessel . that’s sold in uk. You can use the part number 0020039781 and you can get that online heating spares etc .

Ron. I am not saying that your picture doesn’t say 10ltrs. It does what I am saying is it is wrong code VIH 15 CL S refers to the 15ltr store and code VIH 20 CL S refers to the 20 ltr store. You may be able to get the 20ltr in the uk. But it is not supposed to be fitted to the boiler. As per Manufacturers instructions it states that the boiler has a 15ltr store. In the world of gas and gas engineers mate MI’s are god.

 

[Harvest Fields]

You really did not upset me.. I like discussing matters which is totally normal. I just don’t believe I’m so wrong . I can see I can get the storage on English markets with the part number which indicates that you misunderstands the vih cl 15s that’s just the name of the boiler. If you type in the part numbers you can see that the storage comes up with 10 litres each. A lot of Vaillant
Engineers haven’t got a clue if you talk with the, on the phone. Just 2 days ago I spoke with one guy and he wanted to tell me I would need 3 bar mains pressure and 20l flowrates to be able to install this boiler. I had to call a different guy and he told me it was total boll.. the point I want to make is that I strongly believe that it’s the same boiler like Germany with a slight difference in kw output. We have 20 and 26 which is well enough but here in uk is 38kw

The boilers in Germany from what I have been told are a lot more Efficient.

 

[Old Account]

The boilers in Germany from what I have been told are a lot more Efficient.

Soooooooo true 🙂 plenty of different type of boilers.. but again we aren’t in Germany. I get what you are saying above so let’s put an end now ? 😛😀😛😉