15 radiatrors which size of pipe

[pantsmachine]

Hi,

First post so bear with me please. I am doing a loft conversion at the moment. Part of this is going to be a complete heating system. At the moment i run a warm air gas system. Anyway that's getting junked. In total the new system will have 15 radiators to cover the whole house(can't be more technical yet as not read enough to work out specific room requirements). I am planning on a combi boiler with a mains pressure hot water cylinder. The cylinder is mostly to feed an existing power shower(i'll scrap the pump) and fit a new all singing/dancing water extravaganza in the loft conversion(plus the bath downstairs). That's the ground work so what i would like to know please is when i rough in the pipes should i go for 15mm for radiators and 22mm for showers/bath.

Any advice on what i should look out for in a brand new system(i.e good boiler manufacturer) or advice on steel versus copper mains hot water clylinders would be massively appreciated. Finally can anyone tell me where i can get a formula to work out my radiator requirements vs room air volumes?

Thanks in advance. Enjoy your Friday night!

 

[kevplumb]

15 for the rads is just a tad under


calculator here

 

[oilman]

Advice? yeah, get a decent warm air system, or read all of the posts on this forum about problems with wet central heating systems. Would you think there is a little piece of information hidden in all those queries?

 

[kevplumb]

ahh oilman what a little ray of sunshine you are

 

[doitall]

Nothing wrong with a wet system If its designed properly.

Talking about 15mm and 22mm pipe sizes makes one weep for starters.

Combi

you should be looking for at least 28mm from the boiler, pump would probably be a 16/60 but again it all depends on the system, it is impossible to say of the back of a forum

 

[pantsmachine]

Kev thanks for the calculator. Warm air is not an option in this house, existing gas flue coming straight through my new bedroom(couldn't be more dead centre in the room if i planned it so its gotta go. I had read and been told that a 200/250 ltr mains pressure hot water cylinder combined with a good combi boiler would give me all i need as in SPLOOSH for 10 minutes in a 4 jet shower with a 10" ceiling rose. Don't understand 28 mm? Do you mean 28mm pipe running to all radiators? Excuse my ignorance.

 

[kevplumb]

you need to work out all your rads first

then you will know the size of the boiler

then you start on pipe sizing

why a combi if using unvented cylinder

 

[pantsmachine]

Buggered if i know, i thought one went with the other, blunt but honest.

 

[kevplumb]

work on a system boiler

lot less hassle

size of the system it might be worth zoning the floors as well

controlled seperatley

 

[pantsmachine]

Neve thought of that, nice one upstairs will be a cooker most of the time. Thanks. Anticipate steep learing curve.

 

[ChrisR]

Seems to me like there's a lot to be found out before anyone can decide what's best for you. Mains pressure and available flow for a start.

As you're not near me I can advise you to abuse some local plumbers like people do everywhere - get a few quotes, with a lot of asking about what they'd do. Then you'll understand a lot more and may be able to do it yourself.

 

[oilman]

As you're not near me I can advise you to abuse some local plumbers like people do everywhere - get a few quotes, with a lot of asking about what they'd do. Then you'll understand a lot more and may be able to do it yourself.

Just as well it's gas then, just in case you're near me. "cos I don't do gas

 

[traineegasman]

Advice? yeah, get a decent warm air system, or read all of the posts on this forum about problems with wet central heating systems. Would you think there is a little piece of information hidden in all those queries?

as pleasant as ever, thought you`d left??

 

[Agile]

In spit of what some have said, there nothing wrong with warm air or wet systems provided they are well designed.

Combi boilers are fine providing the incoming water supply is adequate as Chris implies.

Depending on the power of the combi, and 28 kw is nowadays the minimum, the heating circuit should start in at least 22 mm and the rule of thumb is rads should be fed with a distribution in 22 mm up to the last 4 kW although each individual rad is fed in 15 mm.

It is not clear if you are planning to do all this work yourself or get a proper heating engineer. Be aware that gas pipework and the boiler installation will normally have to be done by a CORGI registered engineer who can arrange notification to your Building Control department.

Tony Glazier

 

[fitz1]

Have a look at the potterton powermax. Its aboiler and cylinder combined , with good flueing options and depending on size, a hot water supply rate of upto 48 litres per minute at 3 bar pressure.Also , efficiency is about 95 %.