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Any point in over-speccing BTU vs. what is required?
- Thread starter S1llyB1lly
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I could have said a desired room temperature of 21C; though that should have been obvious.
Fooks sake.......
Those not qualified butt out, you know nothing.
OP, the combi your speccing is fine. The 28KW is power to the not water which will give you about 10 litres per minute from one tap.
The boiler may be able to be range rated for the heating which in any case is the installers job not yours to be worrying about
Those not qualified butt out, you know nothing.
OP, the combi your speccing is fine. The 28KW is power to the not water which will give you about 10 litres per minute from one tap.
The boiler may be able to be range rated for the heating which in any case is the installers job not yours to be worrying about
In the time you have over engineered the simplest of jobs I could have fitted the system!!!
= Combi sized to suit hot water forget about heating unless you live in a mansion normal house anything from 28-35kws will be fine
= Any rad valves will be fine you aint on a one pipe system (I hope?!?!)
= Rad sizing is easy Big room big rad small room small rad. You cant really over size if you fit TRVs.
Fire 22mm from the boiler to the middle of where the rads are and spew 10mm to each rad from there. Quite possible to 1st fix an empty stripped house and test it in a day. Plumbing aint big or clever dont over think it.
Saying that if you really want to have a system to be proud of....
Somethings you will need are a low loss header, an Intergash, crimp fittings, 6 pond stats and a 80's alarm clock. With these simple components you can have a system that will run at 150% efficiency.
= Combi sized to suit hot water forget about heating unless you live in a mansion normal house anything from 28-35kws will be fine
= Any rad valves will be fine you aint on a one pipe system (I hope?!?!)
= Rad sizing is easy Big room big rad small room small rad. You cant really over size if you fit TRVs.
Fire 22mm from the boiler to the middle of where the rads are and spew 10mm to each rad from there. Quite possible to 1st fix an empty stripped house and test it in a day. Plumbing aint big or clever dont over think it.
Saying that if you really want to have a system to be proud of....
Somethings you will need are a low loss header, an Intergash, crimp fittings, 6 pond stats and a 80's alarm clock. With these simple components you can have a system that will run at 150% efficiency.
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Bad day at the office sweetheart? 
Bad day at the office sweetheart?
Everyday is a good day!!
you forgot to mention the empty margarine tubs.
No. The individual room kW requirement is dependent on the rate of heat loss and the required temperature rise, e.g -1C to 21C =22C rise. If this works out at 1kW then you need rad(s) which produce 1kW. The problem is that a rad output is not a fixed amount, like an electric fire, it varies depending on three temperatures - Flow, Return and Room. British Standard BS EN442 specify the temperature to be used when testing a rad (75C Flow, 65C Return, 20C Room). This means you can safely compare rad outputs from different manufacturers.
The problem then arises: what happens if the rad is not running at BS temperatures?
The maths is a bit complicated, so I won't bother with it, but if a rad is running with 70C flow, 50C return and a required room temperature of 21C then the output will be 70% of the amount shown in the catalogues. This means that you need to install a rad with a catalogue output of approx 1500W to produce 1000W (1500 x 0.7 =1050).
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OR bang in a 27x45DC and be done then go to the pub
Don't forget to build in an allowance for solar gain and for latent heat from the neighbouring properties in your calculations. In fact if it has a concrete floor make sure you allow for the thermal mass of the property
Or you could take a step back, tell yourself it's a tiny flat and just fit decent sized p+ rads that look about right for the rooms.
Some on here have all day to Google and post drivel. The actual heating guys would've finished it by now
Or you could take a step back, tell yourself it's a tiny flat and just fit decent sized p+ rads that look about right for the rooms.
Some on here have all day to Google and post drivel. The actual heating guys would've finished it by now
Thanks to all for the help, radiators specced, I have gone with Quinn (also considered Stelrad and Myson, however).
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