Atag or Viessmann

[jonCar]

Hi, replacing tanked system and want a good high flow combi.
4/5 bedroom semi-12 rads.
1 bathroom 1st floor
shower room 2nd fl/loft
Boiler going under stairs on ground floor.
Current flow rate mains about 18l/min, 3 bar.
As i've searched on here and can't really find a current opinion can anybody give me an idea either way-

Atag A325ecx supplied and fitted £2300

Viessmann Vitodens 100-W 35kW Combi Boiler s&f £1800

Will the Viessmann suffice or just go for the Atag?

Any advice will be much appreciated.

thank Jon

 

[Gasguru]

Neither...a house that size deserves better than a combi. Go for a traditional system with a cylinder, you then have the immersion heater to give you hot water when the boiler breaks down (they all do).

When choosing a boiler remember the backup and parts availability can be as important as reliabilty...both Atag and Viessman are hopeless for both. Few merchants stock the parts and even fewer want to work on them.

 

[jonCar]

To be honest that is where my first thoughts lay, unvented system as you say.
After talking to builder, heating engineers etc, they seem to think a high flow combi will work adequately.

That said, Gasguru, could you suggest a system boiler and cylinder for the job? would a 180litre cylinder be adequate?
thanks

 

[spireview]

Neither...a house that size deserves better than a combi. Go for a traditional system with a cylinder, you then have the immersion heater to give you hot water when the boiler breaks down (they all do).

When choosing a boiler remember the backup and parts availability can be as important as reliabilty...both Atag and Viessman are hopeless for both. Few merchants stock the parts and even fewer want to work on them.

I do not have any difficulty obtaining Viessmann product or spares. There are Direct next day companies specialising, just google. To say supply is an issue is not accurate and misleading imo. Perhaps 5 years ago but things have improved considerably

 

[Gasguru]

The problem with all combi boilers is the fact that when they pack up you are likely to loose the hot water. Heating's not so bad since a couple of fan heaters will get you by. At Christmas you can wait weeks for a repair or the parts. Immersion backup is must for me in such a property. It's your choice not the builder/installer.

System boilers are only really designed for small properties....the expansion vessel (and sometimes the pump) are too small for larger houses. Manufacturers never tell you this and most installers just don't understand heating systems that well to realise this. A heat only boiler's better with a separate vessel, safety valve, pump etc. Worcester CDi classic would be my choice of boiler given it's a well proven boiler with excellent backup.

Builders are generally completely clueless about heating systems. Whatever you do NEVER pay the builder to have the system installed. They are notorious for subbing the work out and not paying the gas installer (that they may pay peanuts). You're guaranteed to get a complete lash up.

Most builders and installers will want to throw in a combi as few understand how to design and install a proper traditional system.

Depending where you are in the country depends on Viessmann service. Having worked on Viessmann I know they are agro and as an rgi can't be bothered to wait days getting parts and dealing with the poor service. Going to the local merchants who stock parts is far better than relying on couriers...and don't assume these minor players will even have the parts in their UK warehouse.

 

[transam]

fit alot of veissmann heat only boilers

fitted 1 veissmann combi

The all plastic/ rubber combi boiler more plastic than u would have found at a tupper ware party

u can picture the scene at the veissmann R&D dept . How will we connect the heat exc to the plastic manifolds ?? Hmmm

& the answer is

send Otto down to to the german equivalent of halfords to pick up some rubber hoses & 4 hose clips , German engineering at its best

probably all designed & built exclusively for the UK market i.e lets dump our carp into the UK

The above i.e plastic & rubber hoses could be applied to that other german company vaillant ?? (may be ?)

Superior german engineering / quality

b*****ks

 

[jonCar]

Ok, so I go for heat only boiler with cylinder. Would that be unvented then?
Don't want a gravity fed shower etc.

 

[Corgigrouch]

Yep, I'd suggest an unvented too....No problems with ATAG parts, I needed a part that my wholsaler didn't have....Atag sent their own guy through bank holiday Friday traffic to me with the part.

 

[newbuildinstaller]

unvented on 18l/min!!!!

POINTLESS

combi or mains water upgrade or accumulators. 18/lmin would be no better than a combi

oh and ATAG

 

[Gasguru]

unvented on 18l/min!!!!

POINTLESS

combi or mains water upgrade or accumulators. 18/lmin would be no better than a combi

oh and ATAG

Immersion heater backup is essential for a large familly home IMHO. Stuff your combis. If the pressures good then add an accumulator to sort out the flowrate...plenty around for a few hundred quid.

 

[newbuildinstaller]

unvented on 18l/min!!!!

POINTLESS

combi or mains water upgrade or accumulators. 18/lmin would be no better than a combi

oh and ATAG

Immersion heater backup is essential for a large familly home IMHO. Stuff your combis. If the pressures good then add an accumulator to sort out the flowrate...plenty around for a few hundred quid.

Have another quick read of what I wrote...

 

[Dan Robinson]

E325EC pishes all over the Viessmann offering.

Viessmann 200 series are cool... 100 - not so much.

 

[jonCar]

Thanks for the input.
I'm looking at getting the lead pipe replaced, which runs from outside main to stop cock. This would increase flow rate to around 22l/min (so i'm told).

 

[markocosic]

2 bathrooms is the annoying one. "Just about there" with a combi but not quite.


Kid brother looked at:

WB Greenstar 42CDi Classic
(has the gas supply cranked up to 11 to make more hot water than usual)

Atag A325ECX
(has flue gas heat recovery to make more hot water than usual)

Viessmann but the 111-W not the 100-W
(has a modest cylinder built in to make more hot water than usual)


WB unit is physically small but build quality/serviceability was poor and efficiency in hot water mode is poor. The ATAG is a brute of a thing to find space for and a wall to hang it on (timber frame) and the Viesssmann even more so. The ATAG would be cheaper to run but the Viessmann would have the edge on running two showers at once or filling a bath.

Not a lot in it on price on the face of it, but I suspect that installers get bigger discounts on the WB units than the others:
http://www.boilers2go.co.uk/worcester-bosch-greenstar-42cdi-combi-ng.html
http://www.boilers2go.co.uk/atag-a325ec-combination-boiler.html
http://www.plumbnation.co.uk/site/viessmann-vitodens-111-w-35kw-storage-combi-boiler/

He went with the ATAG for ongoing operating cost. (water supply 3 bar static & >20L/min @ 2bar dynamic FWIW)


Having a tank/immersion isn't a good reason to put in a separate unvented cylinder.

You have a dishwasher for the kitchen. Washing machine for the clothes. Use kettle/hob and a camping shower for washing. A 40L one is a perfectly usable shower:

http://www.ebay.co.uk/itm/20-40L-Li...or-Hiking-Water-Heated-Camp-Bag-/141053408130

(40C is good; worth using a thermometer)

 

[jonCar]

Thanks.
this could be a good option-
http://www.plumbnation.co.uk/site/viessmann-vitodens-111-w-35kw-storage-combi-boiler/
do you know if it has an immersion heat element for backup like the Atmos Multi(beast)? It doesn't say anything on the link.