D_Hailsham";p="1236895 said:
Sponsored Links
C
charliechaplinspants
You measure the rooms check the kilowatt range for every room then add 3 kilowatts for Hot water to get size of boiler 
That`s wrong isn`t it.
That`s wrong isn`t it.
Although all heating installers should have attended an Energy Efficiency course and done the assessment and received the Certificate there is a very common misperception of the power to be added for hot water.
The addition should be 2 kW as demonstrated in that on line calculator!
Anyone who states a higher figure is not following the official guidance which is designed to maximise the efficiency of a heating system.
Tony Glazier
Sponsored Links
C
charliechaplinspants
So a combi boiler is sized by measuring the incoming mains flow rate. A system boiler is sized by measuring rads because the hot water is stored am I getting somewhere near ? How do you measure flow rate per second then
How do you measure flow rate per second then So a combi boiler is sized by measuring the incoming mains flow rate. A system boiler is sized by measuring rads because the hot water is stored am I getting somewhere near ?
Not even close
You measure the room to get the right size radiator to heat the room, undersize it and you freeze the nuts off, oversize and you're throwing money away on the installation cost.
2 small rads spaced out can be better than one gert big thing taking up half the wall.
The DHW is sized for occupancy, a couple with 3 kids want more than a couple with no kids.
Most couples with 3 kids started off as a couple with no kids!
Someone I know who is over 60 has just become a father again in spite of his wife always saying she did not want any kids!
The couple with no kids could sell to a couple with 4 kids.
Whilst the existing usage should be taken into account so should the potential useage of that size of property.
Tony
Agreed Tony.
Also the number of bathrooms must be taken into account, A cylinder which is suitable for 2 baths one after the other, may be too small if 2 baths are run at the same time, and a bigger cylinder requires more energy.
Also the number of bathrooms must be taken into account, A cylinder which is suitable for 2 baths one after the other, may be too small if 2 baths are run at the same time, and a bigger cylinder requires more energy.
C
charliechaplinspants
Combi wise, is it sized by incoming flow rate for hot water or not?? How`s this measured???
Charlie, why is it wrong?
Option I would use is access heating load and stick a combi that can take care of that. Let the combi supply HW to kitchen/ utility room and UV cylinder can take care of HW needs (for now and future). Cannot see a couple specifying a small cylinder now and increasing the size as family gets bigger.
C
charliechaplinspants
DP, how is a combi sized for HW requirements? is it as D.Hailsham states, in other words is it sized on incoming flow rate? if so, how is this rate measured? If it`s not sized in this way, how`s it done?
Seem to be a lot of conflicting views here.
Seem to be a lot of conflicting views here.
Thanks for point out my mistake; I meant 10 litres per minute.Oh I'm not so sure
I always work in l/s as it makes the maths easier kW = l/sec x 4.18 x temp rise (K)
C
charliechaplinspants
So if your incoming mains, measured from the cold tap with a flow cup says that you`ve only got a flow rate of 10 litres it would be pointless putting a combi in that boasts 13litres per min Hot water delivery, is that right?
Not necessarily, it will depend on the static pressure as well, you may be able to install an accumulator for example and boost the flow to 15L/min, or even upgrade the service pipe.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
Similar threads
