Vaillant 831 + vrc470f - Hints and tips?

[ALEC1]

thats right delta t drops to about 6c with compensation controls..

Range rating doesn't appear that important either with compensation controls...thats because everything is temperature based, rather than out put based...

 

[MisterG81]

thats right delta t drops to about 6c with compensation controls..

Range rating doesn't appear that important either with compensation controls...thats because everything is temperature based, rather than out put based...

But surely the rules should still apply to a 10-20c temp drop across a rad? (ok maybe less of a delta with a lower flow temp)

At the moment the house is mainly fine with lockshields fully open and TRVs on full probably because the rads have apparently been rightsized for the rooms even down to accounting for lower temps in the bedrooms..

Im merely trying to get the system working as efficient as possible and just wonder if there are (marginally) more savings to be had from more condensing getting the return as low as poss.

 

[ALEC1]

no... the weather comp always maximises the efficiency by running at as lower temperature as possible..

I am afraid the rules as you call it are just the imagination of a few marketing technicians in the UK to sell boilers, not really rules at all..

using the vrc 470 you are using the technology as it was designed in Germany, they too care about efficiency...

the best way to enhance efficiency is to get the curve as low as possible..

 

[MisterG81]

Just to update...

The curve is currently at 1.7 as it has a habit of overshooting in the evenings, with controls set to modulating.
Its currently been taking about 2 hours to get from setback (16c) to the comfort level (19c) in the lounge where the 'stat is.

Ive still got some work to do with rad balancing and flow/return differential, as currently im only getting 3-5c difference at the boiler.
It seems the trade off with trying to restrict flow at the rads lead to noisy lockshield valves though

Is there any way in the diags to see what output the boiler is actually running at? - would be curious to know how far off minimum burn it is

 

[ALEC1]

3-5c differential at the boiler and rads is gone with these controls... You don't balance to get a specific delta t, but to ensure heat is adequately distributed through the house and system

 

[ALEC1]

At that delta t, and with these controls the boiler will be at minimum output.. But one d code will show the fan speed.