Vaillant VRC430 - what works and what doesn't?

[MJN]

I think we're talking at cross-purposes. There has got to be some benefit of familiarity when diagnosing faults whether that's on a boiler, car or whatever. It is this premise that favours the more 'popular' manufacturers.

I've just been reading a thread discussing issues with somebody's Vaillant and the ensuing discussion centred around particular configuration values. There was common agreement on how these should be set in practice and terms like 'this boiler works better with x set at y' and 'I always start with value z and work down', or 'try setting abc at def - it's hard to explain how it functions but it often solves this sort of issue' etc... These were reflections of familiarity and experience with the particular boiler in question and were not something you'd find in the installation manual.

Mathew

 

[D_Hailsham]

There has got to be some benefit of familiarity when diagnosing faults whether that's on a boiler, car or whatever. It is this premise that favours the more 'popular' manufacturers.

I wouldn't disagree with that. However, most faults tend to be unrelated to the particular make/model of boiler installed - pump, diverter valve etc - and what you need is an engineer who can quickly diagnose the cause without relying on the expensive "I'll change xxx and see if it works" method.

I've just been reading a thread discussing issues with somebody's Vaillant and the ensuing discussion centred around particular configuration values.

But those discussions are very much the exception and are usually the result of badly designed/installed systems, wrongly sized boilers etc.

 

[MHOL]

Can the VRC430 be setup to act as a simple programmable room thermostat, ie. not using the WC, but modulating the boiler to achieve a set room temp only?

Would your system work better if you did this? I am thinking of buying a Vaillant 618, VCR430f and VR65, but I don't want the sort of hassle you seem to be having. My thought is that dropping the WC might be a good fall-back if all else fails.

I do this whenever I want to increase the room temperature significantly. For example on return from a holiday. The minimum temperature setting in the VRC430 can be set to a suitable value for the current outdoor temperature and desired heating rate. Also set the heat curve to a very low number (like .5) to stop the controller using anything higher than the minimum. This is like using the temperature control knob on the boiler front. Your intuition is used instead of the controller's. The controller will then always use the minimum temperature as the boiler target temperature and work pretty much as a room stat. Of course this is more fiddly than you might like. Also it can't be programmed for the morning heat up when it would be the best approach.

Once the boiler has been told what temperature to operate to it will modulate or not according to what the return water temperature is.

The heating curve together with the minimum temperature are your tuning knobs for determining how the VRC430 responds to the outside temperature. The handbook doesn't discuss the minimum temperature. This presumably exists because there are temperatures for any installation below which it does not work even though the heating curve may be satisfactory for lower outside temperatures. Using the minimum temperature effectively switches off WC below that temperature. I have 45C as my lowest minimum setting and that corresponds to an outside temp of 5C with a heating curve of 1.5.

I'm clearly below the lower limit of heat demand for sensible operation together with some difficulties caused by microbore and few switched on radiators. Only "hyper-tuning" can make it work. The bigger the house and the fatter and more open the pipes you have , the better you can expect it to work.

We don't have very much to go on beyond that.

Please let us know how it works out.

 

[Modokon]

-snip-
Agreed the high output of the ecoTEC 415 in the first minute can cause overshoot on the flow temperature when WC is used. It can be altered in software but officially thats a job for a very knowing Group Service senior engineer who has expert Vaillant knowledge

And how does a normal bod get this software mod? Seems it should be standard for any Ecotec/430f install given how stupidly it behaves.

 

[Modokon]

-snip-
I'm clearly below the lower limit of heat demand for sensible operation together with some difficulties caused by microbore and few switched on radiators. Only "hyper-tuning" can make it work. The bigger the house and the fatter and more open the pipes you have , the better you can expect it to work.

We don't have very much to go on beyond that.

Please let us know how it works out.

You would think so, but I have 2300sqft, 20 rads and 22mm reducing to 15mm everywhere, but still, have had silliness from this system.