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Safety valve & anti-vac valve question in old londinium
When replacing the anti-vac valve in an 2012 londinium, is it also necessary to replace the safety valve? I understand the purpose & function of the anti- vac valve, but am clueless as to what the safety valve does, and if its function is connected to the anti-vac valve? (I am leery of damaging the boiler messing about replacing the safety valve if it isn’t a necessary mod.)
These important parts are now probably 8 years old and it's probably good practice to replace both.
Two weeks ago I had an issue on my nearly 9 years old Rocket E61 machine. Anti-vac did not close fully and I decided to replace anti-vac, safety valve and big pressostat.
The safety valve opens when the pressostat has a problem and keeps the heating element on permanently. As the boiler pressure then keeps increasing, one does not want it to blow up and therefore the safety valve would open and let out steam until the element is in a dry boiler, overheats and either tripping the heat fuse or melts and trips your home safety circuit breaker.
If the anti-vac and safety valve and pressostat are new and in great condition, they can do their work smoothly for years.
there is no relationship between the anti-vac valve and the safety valve, indeed early espresso machines did not have an anti-vac valve, and instead the machines with started with the steam wands open
you know what the pressure switch does presumably, it is a switch that is actuated by pressure, turning the heating element for the boiler on and off.
the safety valve is very important, as frans has already detailed; it prevents the pressure in the boiler increasing to the point where you create a bomb and the boiler ruptures, a potentially lethal situation. for this reason the safety valve should be replaced when the pressure switch is replaced
the anti vac valve is more in the refinement category than the safety category, as it prevents a vacuum forming in the boiler with the machine is turned off. that said it is important in a thermosiphon architecture as it will cause the group to behave erratically if it is not in good running order