Just plumbed in my ECM Synchronika. Manual says to shut off the water supply line when machine is off?? I've never heard of anyone doing such a thing.

I plan to run my machine 10 hours on, 14 hours off on a WEMO smart plug. Can anyone explain if it's ok to always leave the machine pressurized at 2 bar even when off, and why the manual has this line bolded in the instructions?

Odds are it's a CYA thing due to liability. If the fill solenoid fails open you could get a flood situation. This is true of any machine when plumbed directly to a pressurized water source. I had it happen once with my CMA single group. Completely flooded my kitchen counter and a good bit on the floor overnight.

I've had a machine plumbed in some manner for the last 20 years and only had that one incident that was due to a water level sensor that needed cleaned.

Leave my water pressure on at 2 bar. Only had it for 5 months so not a long term experience.

You could build a bund, like they use in oil storage facilities, on you bench if you are worried.

Simple solution would be to put a solenoid valve inline at the source and wire it to the machine's power switch. There are also leak sensors that can do that.

I too have had a defective solenoid cause a serious leakage problem with our plumbed-in machine. Fortunately my wife and I were right there to turn OFF the water line before there was serious damage.

I will install a leak detection device but until then to continue using our Wemo timer without fear of flooding, I fill the reservoir and when not using the machine manually switch it from 'Plumbed' to 'Reservoir' and re-active the low tank water magnetic water sensor circuit. That way I can continue using the Wemo and if there is a 'fill' demand at turn-on the reservoir will fill the boilers with little chance of severe flooding since the water supply is limited and there is no line water pressure. This also mitigates any possibility of prematurely burning out a boiler heating element due to a low water level within a boiler. It also allows us to us line pressure preinfusion when in use by switching back to water line while in use and with us being present.

YMMV