Viessmann/Worcester/vaillant (threads merged)

[shaaya]

I have done a extensive research and watched hours of videos about all of them and looking for the most suitable boiler for our house.

The house is 5 bed, 4 bathrooms, 20 radiators and maybe in future underfloor heating, 5 people living here and very rarely we use more than one bathroom. Flow is a big thing for me as all showers have a huge rain shower which I have not been able to use as our current combi is small one with flow rate of no more than 12 L/M, so I am looking at a minimum of 18L/M

I know most of you would say I should go for system boiler however due to lack of space I am keen to stick with combi, however I thought maybe storage combi would be a good compromise even though it doesn't work like a system boiler.

Worcester Greenstar 8000 Style 50kW is on the other is very powerful and I was not sure if its power would be able to compensate for the lack of storage unit.

Valliant ecoTEC plus combination store 938 and viessmann 111-W and 222-F both have a storage however I am aware the work differently.

There is highflow 440cdi or 550cdi there as alternative option if you believe that is better.

I have been thinking of 222-F as it has around 100 litre storage, it seem to superior to 111-W however it is twice the price and I am not sure if the price justify its quality. I am aware after the storage depleted it takes about 10-20 min for the tank to heat up and the flow rate revert back to 14 L/M but thats still better than what I get now.

I have heard they are different models of 222-F, are there any model I have to avoid or look for?
Are they worth the price? Do you think 222-F is suitable for our house or should I go for one of the cheaper models? are they as reliable as their manufacture claims? are their customer service good if something does go wrong? is 222-F compatible with NEST, is it even needed as it has its own app?

I am also going to install magnaclean pro 2 and power flush the system and put cleaner and inhibitor products to make sure the warranty doesn't get voided.

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[muggles]

I presume as a first point of call you've checked that your incoming water main can actually handle the flow rate you're wanting? There's absolutely no point going for a big powerful boiler if your mains can't keep up.

I'd go for the Viessmann 222-F of the ones you've listed. It's got the best real-world efficiency, provided the correct controls are fitted of course. Don't fit a Nest, that'll ruin it, use Viessmann's own control. You'll get the best hot water performance from the 32kW, and the heating performance is essentially the same for all three models by the time it's set up correctly. I do have to ask though - if you've got space for the 222F, why haven't you got space for a separate boiler and small fast-recovery unvented cylinder? They'd take up the same amount of room, do many of the same things, and cost much less to buy. For example, an Intergas Xclusive 36 connected to a 125L Joule High Gain on a hot water priority setup would do the same job in about the same amount of space as the 222F for about £800 less, and you'd get a 12 year warranty on the boiler and 25 year warranty on the cylinder as opposed to Viessmann's 5 years

 

[D_Hailsham]

The first thing you need to do is measure the incoming cold water flow rate, at either kitchen cold tap or garden tap. This will tell you the maximum flow rate you will be able to get from a hot water outlet.

 

[Gasguru]

Measure the pressure at various flowrates.
A combi (whether with storage or not) is a mad idea in such a large house...make the space for a cylinder and do it properly.
Storage combis...I'd never have one.
Forget system boilers unless you are in a new build...unless the radiators are very small you will normally have to add an additional expansion vessel and pump.

 

[shaaya]

I am sorry if it is obvious however what is the actual difference between the two.

what are are the advantages and disadvantages of storage combi over system for a big 5 bed house 4 bathroom and 20 radiators, no more than 2 bathrooms will be used at the same time. vitodens-222-f-35kw have 130 litre storage and will provide 18L/M pressure.

https://cdn.plumbnation.co.uk/site/...--100-hc2a-/viessmann-222-f-product-guide.pdf

Am I right to think system boiler would give me a option of larger cylinder, let's say 300 and that would be the only advantage, of course it would be a little cheaper as well but since we have a combi at the moment storage combi might end up cheaper overall.

The flow rate of my house from kitchen tap is around 15 L/M, so if I had vitodens-222-f-35kw does that mean i get 18L/M for 130 litres then it drops back to about 14?

130 Litres would be more than enough for us specially when I know it get heated up in less than 15 min.

If you believe system boiler must be used could have a little technical details so I could understand it myself. as from my understanding vitodens-222-f-35kw is the same as system boiler with smaller cylinder that in built in.

 

[muggles]

You can't get out more than you put in. If you're incoming mains is only running at 15l/min, you'll only get 15l/min out of your storage cylinder. You're right in saying the main advantage of a system boiler & cylinder is that you can have a large cylinder. A separate cylinder will also have a 25 year warranty, whereas the 222-F has 5 years IIRC.

 

[shaaya]

I had a plumber visited my property and he said 222-f are very complex and expensive to fix if they go wrong and he doesn’t think they would last a long time, maybe 10 years.

He suggested Vitoden 200-w with ACV cylinder and he said he can be sure that this system will last a lot longer as there are a lot less electronics and less things that can go wrong and will take the same amount of space.


Also he said 222-f have the vitodens 100 w with a cylinder which didn’t make sense to me,

Also he said the Vitodens 200-W are probably the best and their heat exchanger is twice the thickness of the competitors, im not sure if this is advantages anyway.


Also he said they magnetic filters are not always recommended with Viessmann as the restrict the flow however he will put one that is compatible with this setup.


Also he suggested ACV over more common unvented cylinders, he said ACV get heated up all around therefore they get heated up in 15min so a small unit would be sufficient for a big house.


We have a 5 bed 4 bathroom and 20 radiators and 15l/m flow and all gas pipes are 22m.


Over all I think he knew what he was talking about but I just wanted to confirm his comments with you all experts as well. Any advise of how I should do my set up?



Many thanks for your help.

 

[muggles]

Hmm, not much in the way of accurate information there I'm afraid. The 222-F is essentially a 200-W (definitely not the 100W) with a cylinder bolted to the bottom of it. Good setup where you've got limited space, but obviously the cylinder is only 100 litres and once it's depleted you're down to a lower hot water flow rate until it recharges. If you need more hot water capacity and have space for a bigger cylinder then that's the way to go. That being said, if your mains flow rate is only 15 litres per minute it's not really worth having a cylinder at all - the 200-W combi on its own will keep up with that flow rate. If you do have a cylinder, the ACV is a decent choice, but rather pricey, and the Joule Cyclone High Gain will more than match it for performance at a lower price point.

What setup do you have now? Tanks in the loft and a vented cylinder? You're not going to be able to run four bathrooms (or even two bathrooms) at the same time with a hot water flow rate of 15 l/min. I'd be investigating why your mains flow rate is so poor and finding out whether that could be upgraded before you pitch in to having a fully mains-fed system. You may well end up several thousand down and severely disappointed with the results. You've been advised to do this on both your previous threads you've started on this subject...

 

[shaaya]

What setup do you have now? Tanks in the loft and a vented cylinder? You're not going to be able to run four bathrooms (or even two bathrooms) at the same time with a hot water flow rate of 15 l/min. I'd be investigating why your mains flow rate is so poor and finding out whether that could be upgraded before you pitch in to having a fully mains-fed system. You may well end up several thousand down and severely disappointed with the results. You've been advised to do this on both your previous threads you've started on this subject...

I have a worcester combi boiler greenstar 30i, it doesn't cope with heating the house and shower at the same time, the water goes cold and hot hence we thought we change it.
I have also contacted affinity water to check the pressure coming to the property, waiting for them to get back to me, but apparently if we have 15l/m then thats good enough for them.
I was hoping to fit the 222-f or the 200-w with ACV, but I will go with your suggestion if we go with this system, 150L High Gain Indirect. would you say Joule Cyclone High Gain is better built and more reliable?

Apart from waiting for affinity water to get back to me what else I could do at the meantime, the 15l/m was measure from the cold water from the kitchen. I fill the container myself and measure the time.

 

[muggles]

I think you're missing the point here I'm afraid. With only 15l/min coming in, you're not going to see a significant improvement in performance over what you have now, even if you install a cylinder. You need to sort out your mains water supply issue one way or another before you pitch in to changing your system over. At the moment, a cylinder is totally pointless as it won't give you any more hot water performance than a more powerful combi boiler. You can get yourself a water pressure gauge and fit it to your outside tap to measure water pressure. If you have high pressure but low flow, it's possible that your incoming main is restricting you, in which case a new main would be the first step.

 

[shaaya]

I think you're missing the point here I'm afraid. With only 15l/min coming in, you're not going to see a significant improvement in performance over what you have now, even if you install a cylinder. You need to sort out your mains water supply issue one way or another before you pitch in to changing your system over. At the moment, a cylinder is totally pointless as it won't give you any more hot water performance than a more powerful combi boiler. You can get yourself a water pressure gauge and fit it to your outside tap to measure water pressure. If you have high pressure but low flow, it's possible that your incoming main is restricting you, in which case a new main would be the first step.

I think I did miss your point, thank you for highlighting that again. I will go to buy the water pressure gauge now and test it and update the details.

I was under impression that the flow wouldn't change regardless of the size of the boiler or cylinder but I was hoping a bigger one would at least give us a consistent hot water when showering.

 

[shaaya]

I think you're missing the point here I'm afraid. With only 15l/min coming in, you're not going to see a significant improvement in performance over what you have now, even if you install a cylinder. You need to sort out your mains water supply issue one way or another before you pitch in to changing your system over. At the moment, a cylinder is totally pointless as it won't give you any more hot water performance than a more powerful combi boiler. You can get yourself a water pressure gauge and fit it to your outside tap to measure water pressure. If you have high pressure but low flow, it's possible that your incoming main is restricting you, in which case a new main would be the first step.

ok I checked the pressure now and its is 2.7-2.8 bar, ok so where should I go from here? I checked it by connecting the water gauge to the outside tap that is attached to the kitchen I believe.

So it means I need a new main? is that something I need to get in touch with affinity water or I have to sort it myself and is this a specific plumber job?

 

[muggles]

You can't change your pressure by having a new main. Pressure is set by the water supplier - the only way you can increase your own pressure is to have a tank of stored water and a pump, something like this... https://www.anglianpumping.com/product/mains-pressure-boosting-systems/dab-e-sybox-with-e-sytank

 

[shaaya]

You can't change your pressure by having a new main. Pressure is set by the water supplier - the only way you can increase your own pressure is to have a tank of stored water and a pump, something like this... https://www.anglianpumping.com/product/mains-pressure-boosting-systems/dab-e-sybox-with-e-sytank

That's great thank you for the link, would water suppliers be able to increase the pressure themself so I wouldn't have to install one of these? otherwise i think we have to go for this system

 

[denso13]

would water suppliers be able to increase the pressure themself

No, they wouldn't do that.