open vented close coupled fully pumped heating system

[Franksmith]

hello can u help? what is the likely problem arising from a bypass not being fitted to an openvented closecoupled fully pumped system controlled by 2 x 2 port valves on the heating and hot water curcuits?

 

[Billy Bob Bob]

numatic noise is the most likely cause of not having a bypass

 

[Puddle]

hello can u help? what is the likely problem arising from a bypass not being fitted to an openvented closecoupled fully pumped system controlled by 2 x 2 port valves on the heating and hot water curcuits?

Not sure were close coupled bit comes from unless you have connected heating to w/c seat for added comfort
However not having a by pass before the 2 2 port valves would mean that when valves close down ,boiler pump over run would keep pump on until boiler cools thus pump would be pumping against closed valves causing possible burn out
Also as pump could not circulate hot water from boiler when valves closed(remember when flame turned off,there is a tempurature increase spike) boiler could over heat causing over heat stat on boiler to kick in and stop boiler working until reset
Also auto by pass valves and gate valve sales would drop considerably

 

[Franksmith]

Thank you for your help.

I'm on a course for plumbing and the teaching is a bit, well, wet! I've got an exam tomorrow and this was part of my prep, but i've found the answers... would you have got it?
What is the likely problem arising from a bypass not being fitted to an open vented close-circuited fully pumped heating system controlled by 2 X two port valves on the heating and hot water circuits?


a) 'sucking down' and 'pumping over' the open vent pipe
b) Blockage occurring in the cold feed pipe
c) Rapid pinhole corrossion of the radiators
d) No cool water from the f&e cistern if the system overheats


Answer............





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