Viessmann or ATAG ??

[Brucec1]

Hi,

I'm looking to replace an old Keston boiler in a large 1913 detached property (14 rooms, 16 rads) & am looking for thoughts on replacement options... After ongoing issues with the Keston, reliability is high on the agenda, as is efficiency - any thoughts on Veissman or Atag ??

Thanks.

 

[Deleted member 261]

I used to fit Worcester as they WERE bullet proof but now will only recommend Remeha Viessmann or ATAG. I actually have a Viessmann fitted in my home and if I had the option I would fit an Atag hands down. The problem with these boilers in the past was spares but you can get the parts next working day now. The only problem with ATAG is they are not well known. But who cares? They do make the best boilers

Where did you get the recommendation for ATAG and Viessmann from?🙄

 

[Brucec1]

Thanks for the feedback - apprciate it.

I actually started looking at Worcesters, but heard various reports along the same line as yours (not as good as used to be etc), so widened the search. Atag & Viessman came initially from searching forums like this & their names came up several times as being good/well built boilers - but, as you say, not so well known etc...Sounds like things have moved on and will definitely take a longer look at ATAG.

Cheers.

 

[matty]

We have an Atag boiler. I wouldn't recommend them. Very few heating engineers are familiar with them, and they are quite different in wiring/control etc from other makes. (Eg AIUI the boiler modulation logic makes it unsuitable for use with S Plan or S Plan Plus systems; the way the weather compensator works is not explained well in the manuals; the BrainQ "intelligent" controller is far from intuitive to operate.) This makes it difficult to find someone willing and able to service/upgrade your system.

Even if you do get hold of an Atag-approved engineer, it's become obvious to me that a lot of them don't know what they are doing. Eg we just discovered that our system should have had a low loss header. The first two "Atag-approved" engineers who installed/serviced it didn't know this (even though I later discovered it was in the installation instructions). The next three names I was given by Atag either didn't cover my area or "didn't do" low loss headers. And of course when I finally found a local engineer who knew how to fit one, he had to spend hours on the phone to Atag having its wiring oddities explained to him.

We've just had so many similar problems with our Atag boiler over the last 3 years that I really wish I'd bought a more mainstream brand instead.

 

[oldplumber]

low loss header, explain please heard of not come across yet

 

[matty]

There are some detailed descriptions around on the internet (eg Low Loss Header (what it actually does) on Flickr - Photo Sharing!). It sort of decouples the flow for heating the water from the flow for distributing it, and eg allows you to add an external (powerful) pump pushing a lot of water round all your radiators. The boiler's internal (feeble) pump just pushes water through the heat exchanger into the header, from where the external pump takes it on the other 90% of its journey.

 

[Plouasne]

low loss header, explain please heard of not come across yet

Its just a poncy term for an external mixing manifold, seen lots of them in France

 

[joe plumber]

fitted a few atag's (combi) they seem likea well produced and well thought out unit. my only criticism would be its an ugly beast

 

[Blackcatgas]

We have an Atag boiler. I wouldn't recommend them. Very few heating engineers are familiar with them, and they are quite different in wiring/control etc from other makes. (Eg AIUI the boiler modulation logic makes it unsuitable for use with S Plan or S Plan Plus systems; the way the weather compensator works is not explained well in the manuals; the BrainQ "intelligent" controller is far from intuitive to operate.) This makes it difficult to find someone willing and able to service/upgrade your system.

Even if you do get hold of an Atag-approved engineer, it's become obvious to me that a lot of them don't know what they are doing. Eg we just discovered that our system should have had a low loss header. The first two "Atag-approved" engineers who installed/serviced it didn't know this (even though I later discovered it was in the installation instructions). The next three names I was given by Atag either didn't cover my area or "didn't do" low loss headers. And of course when I finally found a local engineer who knew how to fit one, he had to spend hours on the phone to Atag having its wiring oddities explained to him.

We've just had so many similar problems with our Atag boiler over the last 3 years that I really wish I'd bought a more mainstream brand instead.

Viessmann make excellent boilers, (apart from the mk1 uk only Vitodens a dumbed down product using cheaper paryts for the uk market) The Atag is also a fantastic boiler but very expensive and a little too complex for uk installers (myself included).In Germany to become a heating engineer they go to university and are held in higher regard than the uk, the Germans are 20 years ahead of us in the technology that they are using too. This is my opinion btw I dont want to upset anybody.
It can start getting complex with things like low loss headers for any domestic installer.

 

[tackleburger]

I use Viessman & Vaillant both very good not familiar with ATAG. You shouldn't worry about barrier heat exchangers or low loss headers in a system with 16 radiators. Both Viessman and Vaillant have weather comp available with the Viessman you can't use 240v S plan controls though. You can with the vaillant but need to by their VR 65 control box in order to make it work. You can't go wrong with either my opinion of course.

 

[migoplumber]

low loss header.
just a large bore pipe connected to your boiler in a circle, typicall 2" pipe. maybe just 2 metres long, the boiler pump circulates heat through it, and just enlarges the stored heat capacity and reduces boiler modulation.
your primary heating circs are then tapped into the header. not poncy

 

[Blackcatgas]

I use Viessman & Vaillant both very good not familiar with ATAG. You shouldn't worry about barrier heat exchangers or low loss headers in a system with 16 radiators. Both Viessman and Vaillant have weather comp available with the Viessman you can't use 240v S plan controls though. You can with the vaillant but need to by their VR 65 control box in order to make it work. You can't go wrong with either my opinion of course.

I connected one up the other day?

 

[tackleburger]

Really ! i was told by their technical guy on a course you had to 4 pipe the boiler if you use weather comp? Has that changed. In fact I have heard of numerous problems with people who have done that and found it not to work properly. I though the weather comp system cant prioristise hot water without their controls ie boiler may not run hot enough.

 

[Blackcatgas]

Really ! i was told by their technical guy on a course you had to 4 pipe the boiler if you use weather comp? Has that changed. In fact I have heard of numerous problems with people who have done that and found it not to work properly. I though the weather comp system cant prioristise hot water without their controls ie boiler may not run hot enough.

Sorry Tackleburger I mis understood your post, Ive only ever fitted weather comp to thier combi boilers so Iam totally unaware as to wether you can run an S-plan with the weather compon a sytem/open vent boiler., I thought that you meant that you cant run a viessmann on an s/y plan! doh!😱.

 

[tackleburger]

That's okay mate. I am sure you need to buy the Viessman valve, 4 pipe the boiler and use their cylinder stat to enable a system boiler to work with weather comp. With Vaillant you can use 240v controls if you use the VR 65 control box which is a piece of P to wire up.

 

[Blackcatgas]

I'm a Do It Yourselfer and able to take care of most of my plumbing and other repairs around my home (3rd SFH). We had a kitchen upgrade/remodel in mid-Dec 2006 with granite countertops and stainless steel appliances, one which involved a gas cooktop reconnection.

___________________
Steam shower | Bathroom vanities | Faucets

The reason my company is called Black Cat Gas is because I have a big black cat called Hamish.

 

[safc]

Having worked on ATAGs on and off for the last 9 years i would not reccomend them. Every 3 years you need to replace the burner gaskets and the air vent and safety alve are bound to leak within a couple of years. They have now changed the water pressure sensor with a new type as mst of the old ones always seem to play up. I would go for a lochinvar CPM boiler

 

[tackleburger]

Bit over the top for that his requirements surely - 60KW?

 

[charlie frederi]

Hi safc

wonder if you could advise me fitted new atag condensing combi works on hot water no trouble but wont fire on heating not finished job yet i know most combi boilers have a link you remove to fit the room stat.
would i be right in thinking the atag does not
have a link an you have to fit a room stat to make boiler work in ch mode

thanks for your help

Having worked on ATAGs on and off for the last 9 years i would not reccomend them. Every 3 years you need to replace the burner gaskets and the air vent and safety alve are bound to leak within a couple of years. They have now changed the water pressure sensor with a new type as mst of the old ones always seem to play up. I would go for a lochinvar CPM boiler