Boiler is it the right size?

[Steven Broadbent]

Hi everyone and thank you for any advice and suggestions in advance.

We moved into our property 4 years ago and had the CH upgraded to a system boiler and tank system. It has never warmed the house properly but we just thought this was due to renovating e.g odd rad off wall, bare floor boards, old windows that need replacing.

Whilst looking for new rads I came a cross a site that worked out the btu for each room in total 93,234 btu this is for a large 6 Bedroom house with 2 living rooms and large kitchen. However after checking the output of the boiler (Worcester Bosch greenstar 24cdi) 81,891 excluding any btu for hot water, it seems the boiler is not powerful enough. What do you all think?

 

[Harvest Fields]

Put a bigger boiler in. That can cope with the demand of the radiators.

 

[Last Plumber]

My advice would be to ignore the app's and get a Heating Engineer to look at it. You might need to pay if all you require is calcs but there is a lot to be said for experience.

 

[ShaunCorbs]

Copper cylinder?

 

[Last Plumber]

A Heating Engineer will be able to tell you everything you need to know in a report.
Things such as Heat losses, Boiler size, required emitter sizes, what output you have from what's in place already etc etc.
That's my advice.

 

[ShaunCorbs]

A Heating Engineer will be able to tell you everything you need to know in a report.
Things such as Heat losses, Boiler size, required emitter sizes, what output you have from what's in place already etc etc.
That's my advice.

Also chances are the expansion vessel and pump are undersized

 

[Last Plumber]

Also chances are the expansion vessel and pump are undersized

Yes indeedy.

 

[doitmyself]

I came a cross a site that worked out the btu for each room in total 93,234 btu this is for a large 6 Bedroom house with 2 living rooms and large kitchen.

Online rad calculators are notoriously inaccurate. Frequently provided by rad manufacturers/retailers, who want to sell their products.

The Baxi Whole House Boiler Size Calculator uses the method developed by the Building Research Establishment to calculate the total heat loss from the house, including an allowance for hot water.

 

[Harvest Fields]

Do people still use mears calculators??

 

[ShaunCorbs]

I do, still have my imperial ones

 

[Steven Broadbent]

Thanks to all that replied and thanks once again for the advice. I’ll get a heating engineer to do a report. Does anyone have any recommendations for one near barnsley/sheffield area?

 

[Last Plumber]

Do people still use mears calculators??

Yes.
If you want my opinion you won't go far wrong by using them either.

Whole house method, I do not like and found it a waste of time!
My opinion

 

[king of pipes]

I would say almost certainly your undersized what cylinder to you have ? Set your hotwater timing at a different setting to your heating that way the full output will go to the rads turn down any unused bedroom rads and uninhabited areas , system boilers are renowned for running out of pump power rarely fit them myself preferring a seperate expansion vessel and unvented kit and a properly sized pump . kop

 

[jtsplumbing]

Do people still use mears calculators??

Yes I do

 

[Chalked]

Do the whole house calculation.
But your boiler does look small for a 6 bed house. It also could be a problem with undersized pipework and installing a larger boiler would not make any difference.

 

[Harvest Fields]

Yes.
If you want my opinion you won't go far wrong by using them either.

Whole house method, I do not like and found it a waste of time!
My opinion

I fully agree mate. That’s why I don’t have set prices for installs and I visit every house that wants me to put a quote together.

 

[Chuck]

It has never warmed the house properly but we just thought this was due to renovating e.g odd rad off wall, bare floor boards, old windows that need replacing.

If the boiler has 'never warmed the house properly', which is what you said, it is probably an issue with the circulation, emitters, or controls. If the 'house is okay until the really cold weather comes' then the boiler gets added to the list of possibilities.

A useful piece of information when investigating such issues is to record how much gas you use over a week and the average temperature for that week. There is no need to calculate the losses for your own house, you can just measure them directly.

 

[gmartine]

It does sound undersized, when it's cold shut down the TRVs in three of your large bedrooms and see if that makes a noticable difference.

 

[Last Plumber]

Thanks to all that replied and thanks once again for the advice. I’ll get a heating engineer to do a report. Does anyone have any recommendations for one near barnsley/sheffield area?

I don't know anyone over there but when you find someone, in addition to everything that has been mentioned they should look at pipe sizes.
Out of curiosity what are they leaving the Boiler now?