Cold Water Storage Tank Question

[AJL Plumbing]

Hi All,

Wonder if you can help, went to look at a job yesterday, quite straight forward, moving a indirect 1200x450 cylinder and replacing the cold water tank,questions are-

tank is 100 gal, old absestos, incorrectly supported and bowing the ceiling, this needs replacing but i think 100 gal is to big, is a 3 bed with one bathroom, soon to be a 5 bed with two bathrooms. So first question is do you think a 70 gal coffin tank will be a better option?

Second question is, all pipes off of tank are run in 28mm, cold to cylinder, cold to house, and hot out of cylinder, i would like to replace this all in 22mm, i know this means volume is cut slightly but think again 28mm is over the top?

Any help apreiated, just needed some other opinions!

Thanks, Andrew

 

[justlead1]

Hi. If the system is being extended leave the 28 mm. (the performance will reduced by up to 40 percent is changed to 22 mm ) The client will notice the difference, which may well concern regard your ability. Good Luck

 

[Bernie2]

Hmm!

The bigger size pipe helps with low head, it gives more flow which helps compensate for low pressure.

Just as a pointer and not working it out. In our are, before they took the cold off the main, the standard was 70 gallon nominal 60 actual for a one bathroom house. The pipework was in 22mm, except if the working head was low then it was increased to 28mm on the cylinder cold supply.

So your going to need that 100 gal if you are going to have more bathrooms.

But then, if their cold comes off the main you can recalculate again.

 

[AJL Plumbing]

Thanks for the replys,
the new proposed tank would be mounted in the loft on a platform, with aprox 10 ft of head from bottom of cold tank to bottom of hot water cylinder which is mounted on first floor. Do you think 70 gal tank would be enough?

Regards Andrew


Only one downstairs w/c on mains, the existing bathroom and propossed new bathroom are and will be gravity fed

 

[bobpape]

I suspect that the 100gal tank was installed because at the time there was an issue
with recovery,
So consider the current flow and pressure before making the decision to downsize

 

[justlead1]

Hi. If you have concerns fit a 3/4 inch ball valve the flow rate will fill quicker to compensate for reduced storage. `good `luck

 

[david williams]

do any plumbers get taught about pipe sizing flow rates etc these days.the amount of central heating systems i see nowdays virtuly all run in 15mm plastic(useualy unclipped with big dips}the custermer complaining of lack of heat in rooms at end of system.boiler has usualy gone off by time they get slightly warm.question how much energy (btu/kw ) can you get through a 15mm tube per hour.2 bathrooms ,utility room ,cloakroom all feed off of 22mm.poor training poor workmanship is on the increase

 

[AJL Plumbing]

Yes i did learn about pipe sizing and flow rates whilst at coledge for 4 years, but that was 5 years ago! Forgive me for forgetting, its ok i will consult my coledge paperwork and notes,i thought the idea of the forum was to ask, and get different advice, thank you to those who have helped

Rgds Andrew

 

[david williams]

only 5 years ago and you have forgotten ?.yes it is but you should be able to retain what you have learned longer than 5 years.

 

[AJL Plumbing]

only 5 years ago and you have forgotten ?.yes it is but you should be able to retain what you have learned longer than 5 years.

Mr Williams, are you honestly telling me that you go through every job without ever looking or needing to look at any rule or regulation or calculation? I find this hard to believe, you never need to refer, or refresh your memory? You must either have an elephant memory, or a big head!

 

[david williams]

i have had 40 years to memorise what i do for a living.if you cant remember basic plumbing i feel sorrey for you,as to all the new regs no not at first but as you work under them you assimulate them into everyday practice and have to remember them ,you cant carry all your books with you as for memory yes i have a very good one.big head i dont think so but thats my opinion

 

[bobpape]

If you are all so smart how come no one has answered the question
13000 for half inch and 60000 for three quarter
As they say now... duh

Sorry folks I couldnt resist

 

[AJL Plumbing]

Well done that man !

 

[david williams]

bobpape i see you to are still imperial

 

[Hoopey]

if its an indirect system a 230 litre tank will do, a 130 litre tank for a direct system. 10 meters head will give 1 bar pressure, so maybe keep your bigger sized pipe.

 

[migoplumber]

there are that many formulas and rules to remember, it does become difficult to remember. some calcs that i use everyday stick in my head, others dont.
as ive said before thats why i carry half a library around in the back of my van.
its better to check the book, than remember it wrongly.

the forum is for everyone to ask questions, no matter how stupid the question or answer is.

 

[AJL Plumbing]

there are that many formulas and rules to remember, it does become difficult to remember. some calcs that i use everyday stick in my head, others dont.
as ive said before thats why i carry half a library around in the back of my van.
its better to check the book, than remember it wrongly.

the forum is for everyone to ask questions, no matter how stupid the question or answer is.

I agree totally and i to have have a libary in the van, a quick look at a book is better than hoping youve remembered it correctly,
thanks to all for your help, have decided how i am going to do this now
Regards Andrew