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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.
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.
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.
What kind? P1, P+, K1 or K2?
It all makes a difference especially if it's off 15mm
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.
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.
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Old Account
Yeah I did a mistake in terms of saying it would not run empty obviously it does that’s the writing mistake I made.
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Old Account
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
You also said the store was 20 ltrs mate. Anyway it doesn’t matter I still wouldn’t fit one.
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Old Account
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.
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.
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Old Account
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.
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
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.
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Old Account
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
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Old Account
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.
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