Vaillant integrated controls - worth the upgrade?

[jdp80]

Currently have a ecotec 637 and unistor 310 - rads and towel rails on two CH circuits switched by a Honeywell stat and a UFH circuit with three zones and its own pump, manual mixing valve, Polypipe controller.

It's all newish but has been wired up using conventional 240v switching so I guess I don't benefit from any of the clever stuff like the NTC temperature detection and variable flow temps etc. As a result it seemingly spends a lot of time at full pelt trying to bankrupt me.

Would it be worth 'restructuring' and installing the Vaillant 470F + 61/2 + motorised mixing valve + whatever else to allow the zones to run at different temps?

Not sure how our third circuit for towel rails would work, or how the three UFH zones would work with it - seems like Vaillant only supports two CH zones?

Is it something worth investigating further or am I just tinkering at the edges?

 

[GasSafeRoss]

The boiler will modulate anyway, you have control over different areas of the house with the separate zones. Have thermostatic rad valves for each room.
I believe that its more efficient to have your flow temperature at around 70-80 degrees as the radiators still need to convect that heat out in to the room and if you don't want the room too warm then set the thermostatic radiator valve low.

 

[D_Hailsham]

I believe that its more efficient to have your flow temperature at around 70-80 degrees

So it doesn't matter if the boiler never condenses?

 

[GasSafeRoss]

Nah It would take a lot of condensing to earn your money back that you spent upgrading

 

[D_Hailsham]

Nah It would take a lot of condensing to earn your money back that you spent upgrading

We're not talking about upgrading, which is a pointless exercise as all replacement boilers now have to be condensing, but about the best way of running an existing condensing boiler.

My boiler's spec
18kW input at 80C/60C produces 17.6kW
18kW input at 50C/30C produces 19kW

So you get an 8% improvement in output just by condensing. Are you saying that's not worth having due to the increased convection when running at the higher temperature?

 

[Dan Robinson]

Highly unlikely the OP needs 37kw anyway

 

[jdp80]

Highly unlikely the OP needs 37kw anyway

It tries its best to!

 

[Dan Robinson]

If anything that proves my point even more.

 

[jdp80]

I do like the idea of Evohome - as we have temperature and time requirements (rooms used occasionally, some rooms with setback etc). Also we have four different temperature controllers right now and consolidating would make holidays etc less faff.

I also like the idea of Vaillant's VRC470 - as it just doesn't make sense to me to send 70deg C around the house when it's Spring, only for it to arrive back at the boiler at 65deg because only a few TRVs are open; but to turn it down to 50degC means our hot water will never get above that.

I can't quite work out whether they could work together though. The VRC470 does its own 'indoors' temperature detection doesn't it?
I guess that's where Opentherm was supposed to bridge the gap. Maybe on the next generation

 

[simond]

You can run Evo and VRC470 together, we have done a couple over the last 2-3 years.

However, we haven't found a way of integrating hot water into Evo with this combination.

 

[simond]

Vaillant are unlikely to ever offer OT in the UK. All it would do is lessen the number of controls they could sell.

Generally speaking, the manufacturers who offer OT either;
- Don't have the R&D budget to develop their own
- Have a manufacturing base or large customer base in the Netherlands, where OT compatibility is compulsory

 

[Dan Robinson]

Don't have the R&D budget to develop their own

You mean pinch the protocol and write their own additional commands that make proprietary stuff not want to work without gender benders

Call me a synic.

 

[D_Hailsham]

Generally speaking, the manufacturers who offer OT either;
- Don't have the R&D budget to develop their own
- Have a manufacturing base or large customer base in the Netherlands, where OT compatibility is compulsory

That's a UK urban myth.

I made an enquiry on a Dutch website (normally better English than on here!) where OT is frequently discussed and was informed that OT is not compulsory. It's just that they don't see any benefit in reinventing the wheel.

 

[jdp80]

You can run Evo and VRC470 together, we have done a couple over the last 2-3 years.

However, we haven't found a way of integrating hot water into Evo with this combination.

I saw on some previous threads - was that from leaving the VRC470 installed but linking the Evo's boiler relay to the 240v port on the boiler?

Is the hot water not controllable if you connect a VR61?

 

[simond]

Via Evohome?