Viessmann 111-w

[1982cp]

Hi, I am considering purchasing the 35kw version of above boiler. What have been your experiences with this boiler?

I am also considering purchasing the weather compensation sensor. Does anyone else have this on this particular model? I know that the weather compensation on the 200 range is more sophisticated but is the weather compensation on the 100 range a true benefit.

Finally what controls are you using with this boiler? Ideally I would like the boiler to reduce the room temperature at night and during the day during the week, would this defeat the benefits of weather compensation and modulation and would I be better off simply maintaining 20-21c day and night?

The property is a 60's double glazed 3 bed semi, currently one bathroom, there will be a loft conversation with en-suite in the future and a ground floor extension with underfloor heating so I want to buy a boiler that will keep up with the changes to the house.

The boiler will be installed in an uninsulated garage (flow and return pipes insulated), how much will this impact the flow the temperatures and will this cause the boiler to think the house is cooler than it is?

Sorry, lots of questions but I cannot find too much info on Viessmann boilers (and especially not the Viessman storage boilers), it seems most people install Vaillant or WB, however, neither of them sell storage combis with such a generous tank.

Thanks

 

[1982cp]

Anyone?

 

[simond]

So what is it about the 111 that floats your boat?

Are you aware that Viessmann are one of the most respected German boiler manufacturers in Germany? Yes, I thought so.

Are you aware that their small domestic stuff hasnt been so warmly received here? That their earlier units were a car crash in reliability?

Did you know that the '1' series is a budget range that is not sold in Germany?

 

[1982cp]

I like the fact that it has the internal storage tank, I know it isn't very big, but it will be better than a combi boiler without a storage tank. I originally was going to get an unvented cylinder, but then a friend of mine told me that he has the 222 in his house and how he hasn't had any issues with it since it was installed. His house is much bigger than mine (3 bathrooms, underfloor heating on two of the four floors and 4/5 bedrooms from memory) so that got me lookng a their boilers. Not having a separate tank is a massive plus as space is very valuable.

Yes, I am aware that the early boilers had some issues and it was mainly the 100 range, however, I have not recently heard/read of any problems.

 

[Agile]

It does not matter much how big the property is.

What matters is how many people live there! And that they dont all want to shower at the same time.

Do you realise that the flow rate will limit now many hot outlets you can use at the same time?

More so than on an unvented cylinder.

Have you measured the dynamic mains flow rate or are you rushing out to buy something that just takes your fancy?

Odd how you casually ask if anyone here has this and that. The professionals who give advice here fit all sorts of combinations.

Tony

 

[1982cp]

Apologies, I didn't mean to offend. I am sure all sorts of combinations have been fitted, however, scouring the Internet and multiple forums I have found few posts about the 111w.

Currently two people living in the house, although possibly a baby or two will join us in a few years time. Having two showers running at the same time will not be a very common occurance so I can live with some pressure drop, although the internal storage tank will hopefully avoid this to a certain degree.

Currently there is a 15mm pipe coming into the property, Flow rate is approx 15l per min. When we extend the ground floor we will have the drive dug up and a bigger pipe fitted. For now we will have to live with it as no point digging it up now and then again in 12-18 months time.

I am not rushing out, I looked at the vaillant 938 and also the wb highflow. The vaillant internal cylinder is small in comparison to the viessmann and is comparable in price, the wb is considerably more expensive and can't be wall mounted.

 

[Agile]

No one is offended but I wanted you to be aware that you are not asking homeowners here, but some of the best heating engineers in the country who give their time free of charge to help people.

Your 15 li/min is an open pipe flow rate. To operate a shower properly you need to have some residual pressure to force the flow out of the tiny holes in the shower head. The dynamic flow rate would probably only be about 10 li/min @0.5 bar.

That's adequate for a normal shower! As the only outlet in use! Open the kitchen tap as well and the shower flow rate will become a dribble.

So don't go and buy a 15 li/min rain shower head!

You probably don't see much about the Viess 111 because its rather the entry level model. Viessmann are seen as a rather upmarket boiler and most wanting a storage boiler are not that concerned by the initial cost and go for the 222 with significantly better performance.

Some of the boiler makers are rather naughty and quote a single flow rate for their storage combis. It has to be understood that is only a high flow rate until the store is exhausted after which the flow reduces to a typical combi value. Most are suited to filling a normal depth bath quickly.

The flow rate for any combi boiler or unvented is totally dependent on the dynamic flow rate available from the mains supply.

Tony

 

[1982cp]

I appreciate the input, the three installers that have quoted so far have all quoted for what I have asked for rather than suggesting alternatives.

I like the 222 but I think that if I am going to buy something that size then perhaps I am better off with a separate boiler and unvented cylinder as the space requirement is going to be similar, cost will be similar and the unvented cylinder will provide the benefit of an immersion heater if something goes wrong with the boiler.

Unfortunately as the pipe coming into the property is 15mm I do not know what the dynamic flow rate would be when the pipe is upgraded to 32mm. Do you know if this something Thames water could tell me?

 

[Agile]

Thames Water can usually tell you roughly what the static pressure in the street is. But it is easier and more accurate to measure it in your house.

Then a lot of guesswork comes into play.

You really need to measure your current dynamic flow rate. You need a gauge and see how much flow you can take whilst maintaining say 1.0 bar residual pressure.

Then compare the cross section of your existing 15 mm pipe with the cross section of the proposed 32 mm tube.

Its only approximate but a very good guide.

I am surprised that Viessmann don't put an electric immersion heater into their 222 cylinder. A similar design by Ideal on their Istore has one, but their boilers are far less reliable than Viessmanns so its much more important. As Viessmann give a five years warranty when fitted by a trained installer, than that's because they believe their boilers are reliable.

Tony

 

[DP]

A similar design by Ideal on their Istore has one, but their boilers are far less reliable than Viessmanns

To compare two boilers using different components and dissimilar numbers cannot paint a true picture. Ideal heat engine is alloy, viessman has stainless steel; Viessman is thin on the ground yet ideal was a boiler of choice for builders, developers and anyone looking to buy cheap, so one will certainly hear of more ideals failing as oppose Viessman. IMHO there are no bad boilers, only bad installers cutting corners, resulting in end product that fails exponentially

By the way, I have several ideals that have not missed a beat, yet one client with a Viessman had a few issues

 

[Dan Robinson]

What is dynamic flow rate?

 

[Agile]

Its only 15 li/min open pipe so the current flow rate is less than the 35 kW boiler can heat.

Until the mains supply pipe is upgraded in the future.

Tony

 

[Dan Robinson]

But what is dynamic flow? How does it differ from static flow?

 

[1982cp]

I will check when I get home. I will also call Thames water later to see what the static pressure on the street is. Looking at the Thames water website it seems that they will replace the incoming pipe if it is lead and the water contains a certain level of lead.

Viessmann also offer 5 year warranty on the 111w even if not fitted by one of their certified installers. Two of the three quotes I received were from viessmann accredited installers and one wasn't, the one that wasn't is most likely the guy that I will be using as he has previously completed gas/plumbing work for me and the work was carried out to a good standard.

 

[1982cp]

Thames water were less than useful, they said they did not know and that they legally have to supply one bar of pressure. I just measured the the flow again from the garden tap and it is 14.63, I then fully opened the kitchen cold tap, flow dropped to 12.55. I also asked how much the connection charge would be for when I do upgrade the pipe and they said roughly £500. Seems like a shocking amount for not doing much.