Hot Water Systems.

[GameBreaker]

Ive got a exam on Hot Water soon and i need to know a few things. I understand how the system works and everything but im unsure of the names of pipes etc.

So these what im unsure of:
1 - What is Primary Circulation.
2 - Where is the Primary Circulation pipes.
3 - Where is the Secondary Flow pipe.
4 - Where is the Secondary Return pipe.

Also if you want to add a little more information on anything that could be in the exam please put it in.

Thanks.

 

[stevetheplumber]

primaries go from boiler to cylinder through the coil and back
secondaries are hot water from cylinder to taps larger places have a secondary return to keep water near taps hot thi goes back to the cylinder normally on a tapping about one third down or it can if no tapping is available go back in the cold feed