Best way to run new Combi boiler.

[Unklian]

Hi All.

Thanks for all previous advice.

I'm finally replacing my old Glowworm Spacesaver 40B with a Vaillant Combi.
Can't remember the exact model number but......
I've downloaded their pdf instruction manual and I notice that as well as being able to change the DHW temperature, I can set the Heating water temperature.

My question......Is it better set "low" e.g. 45 degrees so the pump will be running longer pumping cooler water round or, set at 75 degrees so the pump will run for shorter times with hotter radiators.

My thought is, lower would give me a more stable house temperature.

Any suggestions please?

Not available to reply to this topic after tonight, so I'm not ignoring anybody by choice.

Thanks.

Ian.

 

[ALEC1]

you are right... but if its a vaillant why not install the 470 for houses of the 392 for flats..

There are many benefits to these controls, enhanced comfort, reliability (its makes condensing boilers do things they are designed to do) and fuel efficiency... where I have upgraded controls from numpty on-off controls to these type savings have been reported by my customers of up to 20%.. that may be just because they got more parameters to vary..and actively engaged with the controller...

 

[Unklian]

Ah......

So presumably, if it is fairly warm outside, say 14 degrees, the boiler will run "cool".
If it is minus 5 outside, the boiler will run hotter?

I'll have a word with the installer, but is this an automatic way of......
Turning boiler flow temperature down in summer, up in winter?

I can see the reasoning behind the device.

Ian.

 

[ALEC1]

thats the way it works...it does create a more stable temperature inside (assuming that the radiators are correctly sized, which most are) which is more conformable to live in...


Many installers don't like this type of controller, I am never sure why.. I only install these type of controllers and my clients love them, in so far as any one loves heating!!

 

[Unklian]

Cheers ALEC1.

I'll have a word with the installer.

Can go away from the computer enlightened.

Ian.

 

[ChrisR]

You'll be going away from the computer partially misled.

Don't expect to notice your house with a "more stable temperature"; even with old controls and ancient boilers it should be well within a degree. I've measured a lot.
And don't expect savings anything near 20% over the same boiler with the standard control, expecially if you turn the radiator temp up a bit in the autumn and down a bit in the spring.

Something under 1 in 1000 boilers gets these sort of controls installed, and a surprising number are removed - reasons vary.

 

[ALEC1]

People who live with weather compensation and have done for over 25yyrs and take the time and effort to understand what it is doing and why, invariably end up absolutely wedded to it! I regularly get jobs just because of this technology..others just pooh pooh it presumably because they don't understand it

I would make you own mind up...

 

[ChrisR]

Do make your own mind up.
From surveying installers responsible for thousands ( probably about 5000) of installations over the last 4 years, it appears that these controls are fine for a remarkably small proportion, and plain wrong for some. Divorces (it's taken out) to weddings running 100 to 1? Be cynical and demanding of those selling things who make claims without independent evidence.

"Because they don't understand it", does not cover all those who choose against. Salesmen would say that, wouldn't they.