Boiler advice

[tim matthews]

I'm currently totally refurbishing my house. I intend on installing a new central heating\hot water system from scratch.

The house is four bedrooms and each bedroom will have an ensuite shower room (no baths), I don't intend on fitting electric showers. The bedrooms are approx 2 at 4.5m X 5m, 2 at 4m x 4m and the kitchen and lounge are approx 5m x 5m.

What condencing boiler setup do you guys recommend, combi or system boiler with cylinder? What flow rates should I be considering to be able to service 4 showers (although probably not all going to be used at the same time). If going down the cylinder route what sort of size cylinder would you suggest.

I'm planning on having the system installed in my loft space with flue vented through roof.

Thanks for any advice you can give.

 

[EliteHeat]

System boiler with large unvented cylinder, if you have sufficient mains pressure and flow rate.

 

[tim matthews]

Thanks for your quick reply Elite.

How does the following configuration sound from Glow Worm?

Glow-worm 30sxi system boiler
Glow-worm 200 or 250 litre cylinder

If I've got the right sort of set up detailed above which other makes sound I consider?

Thanks again.

 

[Agile]

It depends how many people are to live there and how many/long showers they will want.

I would recommend at least 310 litre cylinder if there are more than two people.

I would doubt that you need more than 24 kW of boiler but that depends on heat loss. If terraced then probably 18 kW will suffice.

Tony

 

[pierrot]

dont get the glow-worm boiler, you will regret it.

 

[tim matthews]

There will be 5 people living there and most will take a shower in the morning around similar times. The evenings will be much more staggered.

So a 300 litre tank as a minimum?

Heat loss will be at a minimum as it is a terraced (with an extension out from the properties either side), also I've added to the insulation in the loft space, added insulation to all floors and external walls whilst replastering. So I take it that an 18kW boiler will suffice.

What is the problem with Glow-worm? What make(s) would you suggest?

Thanks for all your advice.

 

[Agile]

With five showers at 10 li/min they will only get a 10 min shower each even with a 310 litre cylinder. Thats probably enough if they are in a hurry.

But 50 litres/minute is likely to exceed the mains supply capabilities !!!

If its two floors terraced then I would expect the heating to be about 8-9 kW but ideally someone should do a heat loss caculation.

Tony

 

[tim matthews]

Thanks Tony.

That's a big help. There are only 4 showers so mains supply should be ok and hopefully we won't be using them all at exactly the same time!!!!!

I'll start looking around for prices now. Any suggestions on which make to look for?

The help here has been great. Thanks.

 

[ChrisR]

I don't think the penny has dropped. Your mains supply might be 15 litres a minute.
A shower I checked recently produced 40 litres/minute.
In ordinary situations one shower from an unvented cylinder will take water from it at 15-20 litres/minute.

Futher, an unvented cylinder might take all the energy from your boiler, up to about 25kW, to heat the water. During that time the central heating wouldn't be getting much from an 18kW boiler if you have 5 x 10 minute high-rate showers.

Somewhere along the line you may have to change your plumbing (new mains pipe?) your ideas (water storage tank?) or your usage spec, or compromise with a bit of each.