Central Heating Recommendation

[Foncused]

Hi Guys,

I would like some advice please and would like to ask for your forgiveness before I put my foot in my mouth and say something completely inept.

I want to install a new central heating system in a five bedroom house with 2 bathrooms and one ensuite. The current static pressure is 3bar the dynamique pressure with one tap running is 1.8bar and the pressure with two taps running is 0.6 bar. The current mains coming into the house is 15mm and therefore I will upgrade this to a 25mm or 32mm to improve the flowrate which is the issue at the moment.

The demands for hot water in the house are immense! There could potentially be two showers running (ideally want 12 l/pm showers), a sink for the washing up and someone brusing their teeth. This therefore results in a lot of demand of water. I want to know how I can put in a system that could potentially handle all of this.

Do I need an unvented system? If so will this meet the demand? Also will there be sufficient flow rate and if not will I need some form of expansion vessel (not too sure if this would be ok), and could this expansion vessel be applied to just the showers?

I am really confused guys and would appreciate the help. So far I have had plumbers come round and tell me I need a worcester bosch with an unvented system and one guy recommend the alpha flowsmart 50 (given that this is only 18 litres per min I don think its ideal!)

I appreciate any help that is provided and welcome all your help!

 

[gas4you]

The most you could expect out of a powerful combi eg the Vaillant 937, would be 20 l/min on a good day.

I feel you need an unvented cylinder and a system boiler.

I would look at a 300 litre cylinder, possibly a twin coil if you want the option of solar later.

If you want the solar option, have the space and want the best domestic system on the market at present, take a look at the ATAG Q solar.

It is everything fixed to one jig (if you want it to be).

Apart from that a Santon/Megaflo 300 would be good.

You MUST get the incoming main increased as you say. You would be best to go for the next one up from 25mm and run at least 22mm to the unvented cylinder.

 

[Foncused]

Cheers for the reply. I am definitely going for the unvented and I will look at the megaflo. Only issue is that I am only getting 1.8 bar into the house and the minimum for the megaflo is 1.5. If the pressure ever dropped below that then I would be stuffed. Can you recommend any other cylinders? and boilers? I have never heard of the ATAG is there any other conventional boiler you could recommend. I really appreciate your help.

 

[snb]

once you have increased the supply pipe diameter then your pressure drop should be much less and somewhere nearer around the 2 to 2.5 bar.

megaflows will work below 1.5 bar but the flow rates will be lower than quoted