vented or unvented?

[timekeeper123]

I wonder if someone can help? I am fitting four en-suites in four different rooms, each one is going to have a mixer shower. I have been told to fit a 300 ltr unvented indirect mains pressure cylinder and fit a 300 ltr cold storage in the loft. I have measured 18 ltrs per/min of water coming in on the ground floor. I have been told that I will need 40ltrs per/min if all the showers are used at once. My concern is that if I use a mains pressure boiler, and the full demand is used the pressure will drop too low. Should I consider using a vented cylinder instead and use some shower pumps.

 

[timekeeper123]

I would nice if someone who knows about unvented and vented cylinders gave me a technical answer. There must be some experienced plumbers on this forum. Some good advice would be appreciated.

 

[chantelle]

I have been told to fit a 300 ltr unvented indirect mains pressure cylinder and fit a 300 ltr cold storage in the loft.

Then:

I have been told that I will need 40ltrs per/min if all the showers are used at once.

My concern is that if I use a mains pressure boiler, and the full demand is used the pressure will drop too low.

What pressure? The pressure on your boiler indicator,what are you talking about?

Should I consider using a vented cylinder instead and use some shower pumps.[

Make sure it`s a big cylinder if you intend to pump 4 showers from it.
It appears you have already been given good advice already,what`s the problem?
I expect you want to pump each shower because it`s cheaper. Do you have a combi? Do you have a hot water cylinder/conventional boiler set up? What advice do you need other than what you have already been given?

 

[dcawkwell]

Unlikely that 4 showers will be running at once.

18 litres a minute is a bit on the poor side.

I would fit an unvented cylinder and an accumulator tank.
Feed all the showers from the accumulator and hot water tanks.
I would use an ACV tank as these have extremely fast reheat times
and can take all the power from the boiler and more.

Ensure you have a good static pressure of 2.5 bar on the cold mains.

 

[timekeeper123]

Yeah thanks for the advice on the cylinder. All the rooms are bedsit's with working people so it is quite possible that they might be used all at the same time. I don't think I will have 2.5bar mains on the top floor, more likely 1.5.
This is why I'm thinking about a vented with pumps. I just needed someone to give me the best choice with this scenario.

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to chantelle
I would switch to facebook for those KAFA comments.

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I love cheerios in the morning!!!!!!!!

 

[dcawkwell]

If you have fairly poor pressure and flow then go vented with a big
pump to supply the whole house.

Yeah thanks for the advice on the cylinder. All the rooms are bedsit's with working people so it is quite possible that they might be used all at the same time. I don't think I will have 2.5bar mains on the top floor, more likely 1.5.
This is why I'm thinking about a vented with pumps. I just needed someone to give me the best choice with this scenario.

-----------------------------------------------------------------

to chantelle
I would switch to facebook for those KAFA comments.

=============================
I love cheerios in the morning!!!!!!!!

 

[newbuildinstaller]

Booster set up for lots of water.

 

[timekeeper123]

Yes i was thinking of attaching 2x 3bar twin pumps, 1x 3bar pump for 2 showers. (4 showers in all)
Do i run separate hot and cold for the sink to avoid the shower supply so it does not run through the pumps.
Do you think this set up will work.