New Boiler - Open Vent or System?

[dk1uk]

Hi - just looking for some advice on a new boiler (current one is 20 years old and starting to cause problems).

I current have an open vented system. Recently got a heating engineer in to fix a problem with the current boiler and asked him for a quote for a new boiler. He has recommended the Vailant ecoTEC 637 - this is a system boiler which he's quite rightly pointed out would remove the need for a tank in the loft.

Should I be wary of going from an open vent to system boiler? Is there any reason why he wouldn't have just suggested an open vent system? For example, is it easier to install a system boiler and is he just recommending a system boiler to come in cheaper than another quote? I'm just cautious of changing the configuration of something like this in case it leads to other problems.

I'd be grateful of anyone's thoughts.

Many thanks.

 

[neiltheplumber]

the main differences are there will be no need for the tank in the loft because the system boiler will have an in built expansion vessel which means your central heating will be pressurised, also the pump will be integral to the boiler. the new boiler will by more efficient due to being a condensing boiler.

I would be happy with the recommendation you have but you could always get other quoted, be carefull of people flogging you a combi!

 

[dcawkwell]

System boiler everytime. I don't install any open vented
boiler.
A vented system has no place in a modern heating system.

Sealed system keeps all the air out of the system.

If you have a large number of radiators or large radiators have an addition expansion vessel fitted at the same time as the boiler.

 

[mickyg]

37kw?? crikey, how big is your house??

 

[dk1uk]

Great - thank you. There are 20 rads in the house hence the boiler size. The engineer said the Vailant 630 would be OK but said that for another £100 the 637 wouldn't a bad investment. Should I just go for the 630?

Current boiler is 15kw - the house has been extended twice since it was installed and the previous owners didn't bother to upgrade the boiler with the house - we have really felt it this winter!!

 

[ALEC1]

do a heatloss calculation..20 rads is probably about 24kws tops...

 

[Whitespirit66]

You need to do the maths.

http://calculators.baxiknowhow.co.uk/boiler-sizing/

No doubt boiler is undersized, but increasing by 2.5 times sounds a lot.

 

[mogget]

37kw?? crikey, how big is your house??

My thoughts exactly!

 

[ALEC1]

www.idhee.org is another calculator, The baxi one tends to over size too....

 

[swbjackson]

On the subject of sealing the system, I will not do this if there are pipes laid in solid floors, too much chance of a leak.