Unvented cylinder efficiency

[Zagga]

Just decided on new heating system comprising of Vaillant system boiler and the latest Unistor unvented cylinder. The newer Unistor cylinders are B rated however OSO now do an A rated cylinder and was thinking long term the OSO should be a considered option. Going fully Vaillant I understand the boiler can communicate with the cylinder over ebus (?) to control the water heating demand/temperature more efficiently so making extra savings over the standard heat or no heat when using a none Vaillant cylinder.

I know savings using more efficient (Erp rated) products can be negligible but new product efficiencies are only going in one direction so we want to get the best we currently can. With this in mind, has anyone got any experience of the benefits of a totally Vaillant system (ebus communication) over a mix and match one regarding hot water efficiency?

Thanks for any help.

 

[Last Plumber]

You will be able to control your water ( cylinder) temp from the boiler with all Vaillant because you'll be able to use the two stats ( one water, one heating)
This means ( just as an e.g.) you could set your cylinder to 60 deg C, and your radiators or heat emmiters to 55 deg C. Due to them being independent controls.

Just one thought to get the ball rolling I suppose.

Whether or not it matters that much is down to your point of view.

I've got all Vaillant but I bought the Aurostore cylinder and piped the bottom coil too because it's bigger so it heats faster. You could add solar to that at a later date too and the price difference between Aurostore and unistore is not massive.

Worth another thought !

 

[Zagga]

Thanks for the reply.

So if I go OSO you basically set one temperature for the rads and that is then the same for hot water basically meaning rads have to be 60+ degrees to heat the water enough.

Thanks for the tip on the dual coil.

 

[kozak1968]

You would need to have the boiler flow temp set to 65 degrees c for the hot water and if you wanted a lower temp for the radiators then an internal divertor valve fitted in the boiler would be needed. At least this would be required for the Worcester bosch so I would presume the vaillant would be similar. Worth contacting Vaillant for more advise.

 

[Last Plumber]

I agree with Kozak.
Most things are achievable.

By using same manufacturer for all your equipment it's kind of all done for you (design, controls wiring etc).

Efficiency wise, if you do have all the right controls in place you can make the system work just as well using different products than you will using the same. It will possibly end up costing similar Either way to honest.

 

[Stoney Ground]

I agree with Kozak.
Most things are achievable.

By using same manufacturer for all your equipment it's kind of all done for you (design, controls wiring etc).

Efficiency wise, if you do have all the right controls in place you can make the system work just as well using different products than you will using the same. It will possibly end up costing similar Either way to honest.

And possibly more hassle cost if something fails.

 

[Last Plumber]

And possibly more hassle cost if something fails.

Which way ?

Which is more likely to fail in your opinion ?



All a matter of opinion and experiences I know but I'm curious

 

[Zagga]

Thanks for all the suggestions and I think we will stick with the full Vaillant system as it all seems to work together much more seamlessly rather than adding complexity to a mix and match system for a marginal gain in heat loss of the cylinder (0.44 kWh/d difference).

We'll be adding a smart controller to the system and the Vaillant VSmart seems to be pretty much top of the tree in that regard also at present with the added benefit of even more potential efficiency savings.

 

[ShaunCorbs]

Thanks for all the suggestions and I think we will stick with the full Vaillant system as it all seems to work together much more seamlessly rather than adding complexity to a mix and match system for a marginal gain in heat loss of the cylinder (0.44 kWh/d difference).

We'll be adding a smart controller to the system and the Vaillant VSmart seems to be pretty much top of the tree in that regard also at present with the added benefit of even more potential efficiency savings.

Be careful with vsmart few people have had problems

 

[Zagga]

Be careful with vsmart few people have had problems

How so?

 

[Gasmk1]

viessmman 4 pipe and viessmann unvented

 

[1Steven]

viessmman 4 pipe and viessmann unvented

Was just going to add that myself.

Controls hot water and heating separately as well. You can use non Viessmann cylinders with control box. Works out bit cheaper.

 

[Riley]

V Smart is a very clever product with built-in weather compensation. Very good product if wired correctly can cause a lot of headaches if not

 

[ShaunCorbs]

Or when it goes wrong

 

[Gasmk1]

Was just going to add that myself.

Controls hot water and heating separately as well. You can use non Viessmann cylinders with control box. Works out bit cheaper.

it does there are a couple you can use that have sensor pockets also so you dont need the control unit (think this comes with the cylinder anyway)

 

[Stoney Ground]

Which way ?

Which is more likely to fail in your opinion ?






All a matter of opinion and experiences I know but I'm curious

Just feel it is better to stick with boiler manufacturers own controls and system options, makes it easier to get tech support/info. And less hassle if something fails.

 

[Zagga]

Thanks for everyones help on this - really appreciate you taking the time to reply! :biggrin:

Decision made, we are going with the full Vaillant system as it just makes the whole package easier in the future I hope. Point taken about the VSmart but confident our installer knows what he is doing and while the Nest also looks like a good option I still think keeping everything Vaillant will work out great.

 

[Last Plumber]

Good decision !