I am going to go for an intergas combi boiler. ( I am not fitting it0. I am a little confused on a few of the outputs. For instance the have a 36/30, which you would assume has an output of 36Kw has an output of 26.6kw? Is that correctthat is has an output of26.6 kw? I usualy thout that combi boilers were named at their rating.
Intergas combi boilers
- Thread starter tony_m
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What has the installer recommended?
Why worry about such things?
Those figures are the Inputs, not outputs.
Why worry about such things?
Those figures are the Inputs, not outputs.
The installer recommends a 30kw boiler. The boiler choice is mine. Just wanted to make sure I was buying the right boiler.
I would be checking the heat requirements of the property a bit more thoroughly. Do you need 30kW or is it to maintain a certain level of hot water performance?
Has the difference is Kw for heat needed, minimum output and hot water performance been explained to you?
Has the difference is Kw for heat needed, minimum output and hot water performance been explained to you?
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I am open/grateful to an explanation.
Do you KNOW what the heatloss is on your house/property?
Do you understand the different hot water performances/flow rates of the different combi boilers?
For heating, max output is pretty irrelevant. If you are having a combi then you will not need even 24kW to heat your home.
So it boils down to how much water you expect.
9, 11, 13 litres a minute from the 3 main output levels (all makes and models are roughly the same).
That being decided minimum output to heating is second most important. Most places only need their calculated heatloss kW's for a few days a year.
My 4 bed detached house with double glazing and cavity insulation needs 11 - 12 kws to heat when -5 outside.
As I type; with the rooms reaching temperature my controls have set the boiler flow rate to around 45 degrees and the boiler is ticking along at its minimum output of 4kW. Max output is around 15 - 17 depending on what I fiddle with.
It is only cycling on a off periodontally. This is better than having an ovesized boiler going on-off-on-off-on-off all the time.
Do you understand the different hot water performances/flow rates of the different combi boilers?
For heating, max output is pretty irrelevant. If you are having a combi then you will not need even 24kW to heat your home.
So it boils down to how much water you expect.
9, 11, 13 litres a minute from the 3 main output levels (all makes and models are roughly the same).
That being decided minimum output to heating is second most important. Most places only need their calculated heatloss kW's for a few days a year.
My 4 bed detached house with double glazing and cavity insulation needs 11 - 12 kws to heat when -5 outside.
As I type; with the rooms reaching temperature my controls have set the boiler flow rate to around 45 degrees and the boiler is ticking along at its minimum output of 4kW. Max output is around 15 - 17 depending on what I fiddle with.
It is only cycling on a off periodontally. This is better than having an ovesized boiler going on-off-on-off-on-off all the time.
Can you edit your original post and get rid of the link? It is making it hard to read on a tablet? 
We can all find the data for the boiler if needed.
If you don't know your heatlosses then there are plenty of calculators on line and it has been discussed here no end.
We can all find the data for the boiler if needed.If you don't know your heatlosses then there are plenty of calculators on line and it has been discussed here no end.
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1 - Max Heating output as close to property calcs as possibly.
2 - Min Heating output as low as possible given requirements for maximum required.
3 - Hot water performance as required, but no point having any more than needed given 1 & 2 above.
With combi's hot water will always need more kW's than heating. But if you only have one shower then a 30kW combi is pointless. If you can live with a relatively slow filling bath 24kW is best.
What type of property do you have and how do you use your hot water?
1 - Max Heating output as close to property calcs as possibly.
2 - Min Heating output as low as possible given requirements for maximum required.
3 - Hot water performance as required, but no point having any more than needed given 1 & 2 above.
With combi's hot water will always need more kW's than heating. But if you only have one shower then a 30kW combi is pointless. If you can live with a relatively slow filling bath 24kW is best.
What type of property do you have and how do you use your hot water?
Its a ground floor 2 bed flat from a traditional 9" brick built 1900 house. One bath with large shower head and additional hand held shower haed. There is an open plan extension of about 40sq meters with has wet underfloor heating and 3.6m doors.
The extension is cavity wall insulated.
The rest of the exterior wall are insulated plasterboard backed. 40mm. I don't have the u values of the insulated plasterboard.
The extension is cavity wall insulated.
The rest of the exterior wall are insulated plasterboard backed. 40mm. I don't have the u values of the insulated plasterboard.
Right, the 24kw will obviously be loads for the heating. So - measure 9 litres per minute running into the bath and see if that's Acceptable.
If not then try it will 12.
If still not happy then the combi option isn't for you.
If 9 litres is enough then your heating will be slightly more efficient as the boiler can modulate ambit lower.
The boiler is also physically smaller,.
If not then try it will 12.
If still not happy then the combi option isn't for you.
If 9 litres is enough then your heating will be slightly more efficient as the boiler can modulate ambit lower.
The boiler is also physically smaller,.
What are your REALISTIC hot water expectations.
There are only so many ways I can lead you through the same questions.
If you are happy with 9, go for the 24kW. If you really want 12 litres then the 30.
Personally I wouldn't want a combi, but then I demand my bath to fill in <5 mins.
I also happen to have the space for water storage and can get away with a 15kW boiler.
There are only so many ways I can lead you through the same questions.
If you are happy with 9, go for the 24kW. If you really want 12 litres then the 30.
Personally I wouldn't want a combi, but then I demand my bath to fill in <5 mins.
I also happen to have the space for water storage and can get away with a 15kW boiler.
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