Lofty718

I have a VR71 and Sensocomfort with my gas boiler, it's a very good bit of kit but quite complicated with many different settings that even the installer barely understood himself but I worked it all out for myself.

I think oversizing is less of an issue with your boiler since Viessmann 200 modulates to 1.9kw, I don't think theres much difference if you got a smaller Viesssmann

@JohnMo CCT's on my boiler are installed like in the video.

Using a high temperature UFH blending valve with a heat pump is insane if you can avoid it. @JohnMo what do you think?

Is the ivar unimix an electronic mixing valve? I can't find much info on it but looks to be a standard mixing valve

The best way to control UFH is with an electronic mixing valve rather than one on the manifold, they are crap Look into esbe valves, I have one controlling my UFH.

Can you not run the UFH on pure weather compensation rather than using a stat? it doesn't sound like good design Ideally the UFH and rads should all run off one pump at the same flow temp

You shouldn't use CCT's at the manifold. Seperation should be under the boiler not at the manifold

If you get a boiler setup with hot water priority and use a heat pump cylinder with a large coil you could probably use a tiny 100l cylinder depending on the size of your property

https://www.sanctuary-bathrooms.co.uk/designer-3-control-shower-valve-pack-with-head-and-handset?stockcode=46155 I got this set, but were 100 quid cheaper when I bought these valves also allow both outlets to be used at the same time

I've got Crosswater all round and I like them

I've heard being FENSA/CERTASS registered doesn't mean much anyway so you will probably be relying on the good will of the installer to come back and fix this. Unless there's an issue with the construction I don't see how it can't be their liability and considering this is your second issue it points to a badly done install. Were you able to get the issue with your roof resolved?

We are getting a lot of wind driven rain at the moment and this could be exposing the issue. Get the installer back to rectify this, I imagine those windows cost a fortune to buy and install, water ingress so soon is unacceptable. Is the installer FENSA / CERTASS registered?

My 'Plumber' wanted to zone everything off wit heatmiser aswell. But luckily after a bit of research I realised he was clueless

The kudos connect2 shower trays I bought. have the option of two different waste positions Check them out https://www.kudosshowers.co.uk/connect2-shower-tray/

Have you considered upgrading your incoming water main? (if it's lead)

You could acheive hydrauilic seperation by using closed couple tees under the boiler, this is what I have on my Vaillant

@nod I swear you wrote in a recent post that you're not a builder😄

I think this would happen on a standard manifold mixing valve but I have my UFH controlled by an electronic esbe mixing valve wired directly into the Vaillant wiring centre so it offers much better control. I've only run the system on pure weather compensation so far but I'm going to try it with room influence this winter and see how it goes.

Vaillant controls allow a mixture of pure weather compensation and also room influence. I have sensocomfort with WC on my gas boiler

Why on earth would you need to do this? total nonsense lol

It depends how your house is heated, a weather compensated low flow temperature system is a different type of heating to what most are used to and having all of the rooms at the same temperature is not an issue, it's much better and more comfortable.

Most gas boilers aren't running at 100% efficiency, more like 80%

UFH should not be zoned at all and kept as open loop as possible. One zone upstairs one zone downstairs