Refurbishing a 9 bedroom bed & breakfast, bedrooms have a bath/shower in each, central heating uses two C55 Keston boilers, hot water will be three 300 litre unvented cylinders supplied via their own boiler/s.
Could you please give me a rough idea on the size of boiler to supply these cylinders?,would like to heat them within 30 minutes.
Thanks.
Lets call it a 10 bedroom for simplicity and that may have excluded the owner/staff bedroom anyway.
If they are all double there will potentially be 20 people living there. Using the rule of thumb of 50 li of hot per person that will need 1000 litres of stored water. You apparently have 900 li which is fine.
What would surprise me is if you really have a dynamic supply flow rate of 100 li/min @ 1.5 Bar which would be needed to operate that system. But you did not ask about that so we can leave that big problem out of the equation.
That stored water should be adequate to reheat at a leisurely rate. As the cylinder coils probaby do not absorb more that a maximum of 10 kW each then a 28 kW boiler would therefore be totally adequate.
Not only is it not possible to reheat the cylinders in 30 minutes but its not required with normal water usage in a B&B. I dont know quite why but the actual HW usage in hotels is far below what would normally be expected.
However, I can so no reason why the two Kestons should not be able to manage the HW as well as the CH. Its normal to reheat water before the CH comes on in the morning and to keep it topping up as required during the day.
It is not relevant what current gas assessments someone holds. It is what knowledge and experience he has. A domestic qualification can enable installation of any number of boilers up to 60 kW output each operated together.
When asking for advice its always best to listen politely to all the advice given. Its usually pretty obvious who is giving good advice!
Tony Glazier
