question on direct or in direct systems

[garykelly123]

hi all im still at college and just wondering about the above.
how do people tell when going to a job weather its a direct or indirect system that they are going to be working on.
i understand 110 litre cwst for direct system yet 220 for the indirect. but do you really need to get up there to check the size to find out or is there other ways of knowing?
have been told that you can go upstairs and put the bath on full flow and put your thumb over it, and if its mains it will spray out yet if on indirect it will stop is this true?? just wondering how other plumbers out the tell?
also what if an indirect system yet someone has had a extension built and done this with mains pressure.is this possible if so then two systems in one house how do people tell or know as maybe the customer would not know or inform you this themselfs.
and help would be greatfull

 

[PlumbBobBob]

basically indirect cylinders have coils in to heat the water, direct doesn't. size doesn't really come into it. direct can also be low pressure like indirect. hope this helps.

 

[samh]

It depends, do you mean hot water or cold water?

 

[garykelly123]

so how would you know steve if that cylinder had a coil inside or not,and to the last post what if it is cold water, would you just check all taps or what??

 

[PlumbBobBob]

if it had a coil you would see two pipes connected to the side you wouldn't have these with a direct cylinder. direct and indirect only apply to hot water. the cold water will be either tank fed or mains.

 

[dancinplumba]

sometimes direct will have two pipes into the sides, usually from old back boiler but they are usually close together, indirect has two storage tanks, one for dhw and one for heating system.
steve

 

[garykelly123]

thanks