New house renovation: boiler and unvented cylinder advice

[Duality]

Firstly this a great forum, this is my first post but I been an observer/reader for a while! OK so back to questions at hand.

The house:
I bought a new house around 1970s build 4 bedrooms full refurb. New radiators and pipework. Plastic pipe under the floor leading to copper coming out of floorboards.

• The property has 2 bathrooms and 1 en suite
  • 2 showers with shower bars
  • 1 bath with shower mixer tap and separate shower bar
  • (so essentially 3 showers)
• Around 13 radiators
  • 3 towel rads
  • 1 kitchen tall rad
  • The rest double rads
• 2 zone under floor heating
  • Kitchen
  • Hall
  • Approx. Around 21sqm

The system
I'm wanting a system boiler with 300ltr indirect unvented cylinder.

Question no. 1 which boiler?
Boiler
Looking at vaillant 630 or 637
-or-
bosch 30cdi or 35cdi
I checked online at kW requirements and 1 site says 29kw other says 30kw. Any advice on bosch vs vaillant? Which should I go for?

Unvented cylinder
Q. 2 which unvented cylinder to get.

Looking at 300ltr but no idea which one to get. My builder is insistent on getting a joule cylinder. I've searched extensively on this forum for them but a lot of posts talking about them are very old and even a Google search doesn't give many results (hence my post)
Which unvented cylinder (at a decent price range - I know megaflo is to expensive but is it worth pursuing the extra?). I heard people mention fabdec is good?

Any advice please would be really appreciated! Total newbie.. Which boiler and cylinder to get. Something easy to get parts for and reliable please!

P.s sorry for the long post

 

[Riley]

Id go Vaillant id go 637 and rate it down however I would get your installer to properly size your system and there is nothing wrong with Joule cylinders. I've fitted a good few but stelflow are another favourite

 

[Duality]

Thank you for the prompt response. Really appreciated!

Do you know how Joule are for ok getting parts for? I tried calling a few plumber merchants to ask what they think of the system/availability, only to find most either hadn't heard of it or hadn't had any experience with it.

The last thing i want to do is spend so much money on a full system and then find its not maintainable in the future!! so a bit worried about it at the moment :s

A lot of the people i called suggested go for Fabdec as they originally made megaflo or pay the extra and just get a megaflo as its more reliable. Not sure if thats a good route to go down. Or would you suggest any other brands cheaper than a megaflo but good reliable units?

 

[AMW]

Also make sure your installer is G3 competent as not just anybody can fit unvented cylinders. The most recent unvented cylinder I fitted was a rm cylinder, personally I've not come across joule.

 

[Scott_D]

Matching Vaillant cylinder?

 

[Duality]

nks for all the advice guys. Looking at maybe going for a 'main' unvented cylinder now. I've been told they are made by Heatrae Sadia (Megaflo). Any one think thats a good enough choice?

 

[kozak1968]

I've fitted a few mains and they are o.k. My choice would be Vaillant because all the tappings are in the same area, ie the front. Telford Tempest are good quality aswell.

 

[macackau]

Plumb Center own brand unvented cylinder is also a Heatrae Sadia and as its a plumb center branded one it's a lot cheaper, it has an external expansion vessel. 30kw sounds quite a lot for a 4 bed house though?

 

[Scott_D]

Have you checked flow rates and pressure?

 

[Welder]

As scott is alluding to, there is far more to a decent system than the kit you have installed. You can have rolls royce gear put in, but if youve a water meter installed youll be able to pee quicker. My advice, get one of the reps to look over your installation and specify. Id try Ozo first as its reliable and spares are reasonable. Cant say that for any megaflo.

 

[Gasmk1]

I like OSO cylinders as all pipes come into the cylinder from the top so easily removed, if they are close to each other a viessmann boiler and cylinder. But as someone has pointed out you need to check the water pressure.

 

[walterwhite]

I'd go with a Vaillant cylinder with Vaillant boiler & Vaillant vSmart controls. Comes with weather compensation....