viessmann 050-w and viessmann generally

[Desktop987456]

Hi, ok thats good then, it didn't come on last night, my night setting was 18 deg, so obviously it wasn't required, overnight temps outside were 11 deg. during the day it used about 28kwh and the house felt really comfortable. It'll be a bit of a learning curve according to weather, can always alter the weather comp curve to suit if required. Yes you are correct, EPH is just an on/off switch.

@bobbyt - Didn't want to hijack someone else's post (PM me if you can) but could you please let me know the heating load (how many rads) you are running on CH with 28kwh per day consumption? That's really low, I am interested to know and compare it to my system which is also Viessmann Vitdodens 100-w heat only boiler. I am not in UK though.

 

[Knappers]

It's difficult to advise without seeing the system and getting a good idea of what you want.

It's a good idea to future-proof but it could be done in different stages. Just make sure that whatever your putting in is up to future spec.

Most boilers aren't setup for HW priority (with dual flow temps) and its a fairly niche install.
I think Intergas, ideal & Vaillant have options tho.
(I've just completed one with a Worcester 4000 but I can't reccomend it as not technically allowed).

I think the point that was being made before is that your probably better off with a good reliable local engineer than with (what some may consider) an over complicated installation.

I guess the question is how much do you want to spend?

Yes a system boiler with a high gain (dual coil) UV HW cylinder, resized rads for 50°C flow temps, HW priority and load/weather compensation would be ideal (also zoning/smart TRVs may be an option)!
But they can also all be done independently without any issue...

Regarding pressurising your system, I think your best taking advice from your engineer but it would have to be a particularly ropey system for it to be an issue. As said the pressures aren't very high.

glad you are happy with your system. i've decided that weather comp is over-hyped. not saying it doesn't do anything, it's just diminished returns; your savings are going to be because it's a modern condensing boiler with low flow temps. the weather comp doesn't do much in addition to that, and i assume the EPH controller is on/off mode as it can't work in opentherm mode at the same time as weather comp.

i am going with a main eco compact 25kw and eph cp4 control. i think that'll get me 95% of the way there.

have you thought about what would happen to your bills if you turned it off at night?

Over-hyped!
Manufacturers have been hyping online control and WiFi with little emphasis on weather comp.
The only 'hype' I see is from old guys like me and other experienced engineers.
Domestic market is probably 30 years behind commercial with regards to weather comp - its hardly a new fad!
I stand by my opinion that altho literature will only state 1-2% efficiency gains, the added comfort would actually allow the economy-minded consumer to drop their temp atleast 1deg and maintain the same or better comfort level.
Then your looking at 10-15% saving.
It's one of the few truly usefull advancements in any of the modern controls (IMO)