Will my new boiler be overloaded???

[tz105]

Hi everyone,
can I please start by saying that plumbing is not my forte, in fact I know very little about plumbing and so far have been relying on my plumber to spec everything correctly.
But I have some concerns, and would like to gather more information.

We have very recently had a new Grant Vortex Pro 26KW Combi Boiler installed. (This was installed as part of an extension project we are currently undertaking, so not all our radiators are installed yet ).

When I add all the sizes of our current and new radiators, they come to 29KW. This boiler has a max of 26KW, so can you please tell me what the implications of this are.

I am worried that I will have issues with radiators, and they will not work in the winter when I have them all on at same time. Am also worried that I will not be able to upgrade or replace any radiators in the future, eg replace some of my old single radiators with doubles.

Please has anyone any advice on this

Much appreciated

 

[doitmyself]

We have very recently had a new Grant Vortex Pro 26KW Combi Boiler installed.

Combi boilers are sized so the provide the required hot water flow rate. This means they are often oversized for central heating.

Use Whole House Boiler Size Calculator or Baxi Whole House Boiler Size Calculator to find out the heating requirement of your house. You may have to do this for the original house then add in the new extension (which should have been calculated when applying for Building Regs approval.

It doesn't matter if the rad total is greater than the heating requirement. It just means that the system will run at a lower temperature to supply the required amount of heat. This is a GOOD THING as the boiler will run in condensing mode more often, which reduces fuel consumption and SAVES MONEY.

 

[steadyon]

I think you perhaps need to concentrate more on the space heating requirements of your house. This is essentially the amount of heat required to keep your property at its chosen temperature, allowing for the heat lost with an outside temperature of (normally) -1 degree, and also allowing about 10% more for heating up from cold.

If this value (there are various calculators available on the internet) is less than 26 KW you'll have no problems. You could re-do the calculation with some imaginary extensions to allow for more space.

Don't forget that the radiators you have may be able to "supply" 29KW, but that doesn't mean you need that much heat.

 

[Millsy 82]

How big is your house?

 

[lame plumber]

if your house is insulated properly and upto recent buildings standards you will probably find that your rads are far to big and you'll not notice any problems in the first place. You should be more concerned at getting the right sized rads in the first place.

get your heating installer to explain his calcs if your worried, remember a little knowledge is dangerous, it can cause friction between you and your installer if he is correct in what he is doing.

 

[tz105]

thanks all for your great replies.
am confident the rads are correct size as plumber calculated room sizes, heat loss etc.
will wait to all radiators installed and hopefully there will be no issues.
Will have a nosey at the Heat Calculators and not concentrate on just rad output

 

[Nostrum]

Must be a fairly substantial property to have a heat loss of 26kw