Solenoid Valve in Electric Shower? what is it for?!!

[jacobball]

One quick question for any experts out there who may know:

What is the point of a solenoid valve in an electric shower?

If the water flows through the unit and the pressure of the mains water going through it activates a micro/flow switch that puts the power on to the element anyway, what is the point/function of the actual solenoid????

 

[swbjackson]

The solenoid valve opens to let the water through.

 

[jacobball]

i know this - but why the need? how comes the dial is not sufficient enough, like for an instanteneous water heater? wouldn't turning the dial not just allow water through and do the same job? i don't get what the point of the solenoid is? ........

 

[swbjackson]

The dial doesn't shut off the water completely on most modern showers. If the flow is too low through the shower it's possible for someone to be scalded.

 

[jacobball]

oh i see, the dial doesn't fully shut the water off. ok, thanks for explaining that.

one other thing though: if the flow is too low, the element may not heat up (the pressure would be too low to activate the micro/flow switch).

so how does the solenoid stop people getting scalded then? sorry for all these q's!!

 

[swbjackson]

If the switch sticks you could end up with the heater on constantly and with a low flow the overheat cut out may not work. also a lot of modern showers now vary the power rather than the flow rate to adjust the temperature..

 

[jacobball]

ok thanks for the info. basically: with the shower off, the solenoid is closed and water cannot enter the shower unit. thus it is a safety device, as if the micro/flow switch sticks, then no water (even a small amount/flow) will be able to flow through it.

i thought that the element in the electric shower always heated up the same temp, but by turning the dial (to make it hotter) the fkow was reduced through ther unit, to allow it to heat up to the hotter temp. and thus a faster flow meant that the water wouldn't heat up as much.....

 

[swbjackson]

That used to be the case but with the advent of thermostatic electric showers it's a lot more complex. Cheapo ones are still like that.

 

[jacobball]

oh i see, the more complex ones, which have thermostatic control and thus are a lot more safer.

basically the shower then varies how many volts go to the element, depending on how high the temp is!?