old rother boiler cylinders

[hotpants]

i have come across two old rother boiler cylinders connected in parallel. the vents meet and terminate in adjacent loftspace. but before they meet they both drop (pipe drops) towards the ground beside the cylinder. the pipes are open at the end and seem to serve some safety function. a safety valve on the other side of each cylinder drops towards the ground in a similar fashion also. can someone tell me what these devices are and the funtion they serve?

i would really appreciate a detailed answer as i do not understand their purpose.

thanks a lot for your help guys!

 

[stevetheplumber]

usually these were three way valves so you can isolate one or other cylinder without cloing it of from the vent valve is either from cyl to vent or from cyl to open end
that way a cylinder cant be closed of while still being heated by the boiler

 

[hotpants]

steve the plumber can you descibe this a bit better or if you would could you draw me a diagram of what you mean to [email protected]

i would really appreciate that!