Hot water cylinders

[Dannyparty92]

I know a vented cylinder can implode went you bung the vent and let water out but why wouldn't this be the case on an unvented system if you shut the supply off and drain water out what's replacing the water? I only found out about vented cylinders imploding recently because as the vents blocked and if you let water out there is nothing to replace the water so could someone explain to me how come this does not happen to unvented cylinders? I guess the theory behind this is because nothing is replacing the water when you open a hot tap this creates negative pressure in the cylinder and the atmospheric pressure crushes the cylinder?

 

[buckley plumb]

not sure. could see draining would cause the same imploding but not just isolating then opening a tap

 

[Billy Bob Bob]

unvented stainless cylinders are generally a lot stronger than copper vented ones,can withstand higher pressures and dont tend to implode however if fitted by a numbnut can explode,bit like a bomb going off

 

[Dannyparty92]

I'm guessing because our only causing a small amount of water to be removed from the cylinder when you isolate and open a tap?

 

[SimonG]

Just search You Tube/Mythbusters/Unvented Cylinder can't beat a good bang

 

[Dannyparty92]

Thanks for the quick replys .

 

[buckley plumb]

unvented stainless cylinders are generally a lot stronger than copper vented ones,can withstand higher pressures and dont tend to implode however if fitted by a numbnut can explode,bit like a bomb going off

think the question is collapsing when iso is turned off and the hot tap opened not exploding mate

 

[Dannyparty92]

Yeah imploding rather than exploding but yeah the stainless steel comment makes sence cheers gas man.