BTU rating for shower, bath, handbasins?
- Thread starter Mike2007
- Start date
H
holty
if you mean what to add for boiler sizing, for dhw e.g cylinder. just add 3kw=10236btu
Sorry if I did not explain properly.
Sizing the boiler to run at its best...underfloor heating running at max, rads running at start up max. Customer turns on a tap for a bath and combi has had enough!
Trying to judge if its to be 18-25kw or 25-32kw ??
Sizing the boiler to run at its best...underfloor heating running at max, rads running at start up max. Customer turns on a tap for a bath and combi has had enough!
Trying to judge if its to be 18-25kw or 25-32kw ??
When there is call for HW on a combi system, the CH is essentially switched off whilst the combi heats the water - ie. the two are never working simultaneously, so what you're saying shouldn't be a problem.
Combis tend to have two ratings, but the one that's usually quoted will be for the HW, not the CH. The CH rating will usually be more than adequate (likely, but will obviously still need checking).
When sizing a combi boiler, you need to take into account how many bathrooms/HW outlets there are and how likely it is that more than one will need to be used at once.
I would imagine that a combi rated between 18-25kW will be suitable for properties with 1 bathroom and the flow rate will be fairly low. One rated at 25-32kW will obviously provide HW at a faster flow rate, but you'll still be struggling to provide a good rate to more than one outlet at once. Only the higher rated combis are reported to do this and even then, it's presumably all dependent on your incoming mains flow rate and pressure etc.
I'm only a DIYer incidently, so only have a basic understanding of all this. When you say 'customer' - does that mean you're a pro ? Better read up on combis quick-smart !
This will give you a starting point for rating a combi : www.worcester-bosch.co.uk/index.php?fuseaction=boiler.selector
Combis tend to have two ratings, but the one that's usually quoted will be for the HW, not the CH. The CH rating will usually be more than adequate (likely, but will obviously still need checking).
When sizing a combi boiler, you need to take into account how many bathrooms/HW outlets there are and how likely it is that more than one will need to be used at once.
I would imagine that a combi rated between 18-25kW will be suitable for properties with 1 bathroom and the flow rate will be fairly low. One rated at 25-32kW will obviously provide HW at a faster flow rate, but you'll still be struggling to provide a good rate to more than one outlet at once. Only the higher rated combis are reported to do this and even then, it's presumably all dependent on your incoming mains flow rate and pressure etc.
I'm only a DIYer incidently, so only have a basic understanding of all this. When you say 'customer' - does that mean you're a pro ? Better read up on combis quick-smart !
This will give you a starting point for rating a combi : www.worcester-bosch.co.uk/index.php?fuseaction=boiler.selector
If you fit a Vaillant then you can go as big as you like for hw then range rat the ch down to what you need.
The UFH part will look after its self with the UFH pump circulating and mixing the flow and return to acheive the lower operating temp required by the UFH.
I personally never fit less than the 31Kw combi, this gives 24Kw to ch if needed.
The UFH part will look after its self with the UFH pump circulating and mixing the flow and return to acheive the lower operating temp required by the UFH.
I personally never fit less than the 31Kw combi, this gives 24Kw to ch if needed.
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