Load compensation

[Knappers]

I know this 'which boiler' thing has been done to death but with more manufacturers offering higher modulation rates I'd really like to get my head around it.
When it comes to reccomending the best im looking for high modulation and good load/ weather compensation options.
Whos leading the way when it comes to intelligent controls and at what point (if any) does 3-4kw min output become pointless?
What boiler and control packages can I expect to maintain the most constant temperatures, where I'm likely to find the boiler happily chugging along with a 30deg flow temp?
Which controls are going to automatically adjust their heating curves and which allow manual adjustment?
Which will use weather or room compensation and which use both?
I'm really fed up with looks, price, percieved reliability and fancy but mostly pointless wireless controls.
I can sell myself to my customers and think its my job to look at my boilers from a more technical perspective, the manufacturers don't make that particularly easy (atleast not to any depth).
I'm currently a worcester guy after getting frustrated with vaillants rubber hoses, pressure sensors and old fashioned controls, I'd consider viessmann but haven't seen enough to change over.
What are your thoughts?

 

[Scott_D]

Good post
I did try pushing better controls for a while but have given up for now and fit EPH combi pack 4 or nest/hive for smart stats.
Wiring outside sensors, setting curves trying to explain it all to the end user who doesn’t really care.
Most people want to turn on the heating and have a hot radiator within a few minutes and will complain it’s not working if this doesn’t happen.

 

[John.g]

If I was a customer I would like a boiler with a minimum output of 1.5/2kw and one that doesn't trip on a 30 deg detlaT between flow/return temps which may mean a SS Hx.

 

[Ric2013]

Agreed, John. We size systems for maximum output, but it's very rare that we need anything near that output. I see one of the Veissmann Vitodens 200 models claims 1.9kW running at 50/30.

 

[John.g]

Modulation ratio is the answer, years ago, I think it was a Vokera Mynute? had a 10:1 when most of the others were offering ~ 5 or 6:1. Someone posted on here quoting some manufacturer that is offering something like 1.9kw min output with a 36kw rated output.

 

[gmartine]

It's the 200-W that has a mod ratio of 17:1, trouble is not everybody wants to spend 2K otherwise that is all I would fit.

Try explaining weather comp to an elderly couple who doesn't think the heating is on because the radiators aren't hot. I have on the odd occasion bought some high viz thermostats to place in some essential rooms and just say look at those, if its 23 deg (elderly) its ok. I notice Viessmann have adopted Tado as their third party controller of choice, I like it but it can add up cost wise.

 

[Knappers]

Its good to have the options tho, I'm trying not to fall into the trap of chasing points with the manufacturers. Worcesters new 8000 has a good modulation and some decent sub menu adaptability on the 'easy control'
Can't deny the viessmann is more advanced but the cost is a little off-putting.
I like the idea of the 111-w too but never fitted one
Are there any others with a 10:1 or better modulation and some decent controls?
Is viessmann using open therm protocols then, does anyone know about the functionality on the tado or if nest have ever actually started to use the function properly.
(I wasn't impressed with the changes to the nest interface last time I fitted one)

I know customers aren't bothered or don't understand but that doesn't mean I'm going to stop making reccomendations.
Currently offer worcester as premium option and baxi as second but could do viessmann as premium, worcester as middle and baxi as 'budget'?
(Imo Ideal doesn't make the cut - its a job for someone else)

 

[Gasmk1]

the cost of the 200 is a bit off putting but having had one in my last house found the cost worthwhile, I don't think it is much more than the high end boilers but the controls tend to be. plus isn't the new 200 wifi already in the boiler.

 

[gmartine]

Yes 200-w has built in WiFi for use with the ViCare app but the rest of the range don't.

@Knappers

Tado utilise Open Therm on the Viessmann range without a problem. Obviously it is a modulated command limited by what the boiler max is set at however you can also request Tado set the max flow temp but this is a one time deal and obviously not ideal if you want to change it, Viessmann recommend 75deg.

 

[Knappers]

So is viessmann and WB it?
What happens when we move to system boilers?
At home I fitted a vaillant boiler and cylinder combo and was quite impressed with the interconnectivity with VRC 430 controller.
Has anyone in history ever fitted worcesters integral diverter (I've never seen one).
What happens with all the load compensation when HW is on, are we supposed to plumb s-plan with HW priority?
Infact I'm a bit disturbed by how little I know about the protocols on system boilers☺