I recently have the same issue described in this post with my Strega: Bezzera Strega pump not engaging/

If I turn on the machine fifteen minutes before I make coffee, the machine works perfectly fine.

If I turn the machine on an hour earlier, the pump may not work, including pressing down the micro switch and the auto refill of the boiler after I drain the hot water from the boiler for testing.

• Then if I turn off the machine, wait for a while(15 mins for example), and turn it back on, the pump work again and auto refill water into the boiler. the micro switch also can turn on the pump.
• But It won't work if just turn off and turn on again immediately.

It seems that the issue is related to the standby time or the machine becomes hot.

Because the original post can't reply, so I start a new post, hoping someone has found a solution and can help.

Thanks!

IMO, we don't have enough data to respond intelligently. Would you please hook your voltmeter to the pump leads and run the machine to create the failure condition? The pump is connected directly to the neutral and the pompa (pump) line of the GICAR. You/we need to know if the pump is getting power. If it is, then there's your answer; it's the pump. If it isn't, then it could be several things but don't assume anything, measure. For example, don't rely on hearing the brew switch click; put an ohmmeter on it and see if it goes on and off properly.

Thank you for your advice.

Today I finally had time to check the circuit according to your method (open the machine's case and connected the test wires at the pump's positive and negative sides). I found that the voltage is normal. When the switch is pressed, the voltage connected to the pump is always around 284V(The voltage display is too high, probably because the battery power of my multimeter is too low), no matter if the pump is working normally or not working.

So, can we say that the problem is in the pump?

bold wrote:Thank you for your advice.

Today I finally had time to check the circuit according to your method (open the machine's case and connected the test wires at the pump's positive and negative sides). I found that the voltage is normal. When the switch is pressed, the voltage connected to the pump is always around 284V(The voltage display is too high, probably because the battery power of my multimeter is too low), no matter if the pump is working normally or not working. So, can we say that the problem is in the pump?

Do I understand correctly that you took the case off, hooked the meter to the pump, and found that there is mains voltage on the pump; then you warmed the machine up well to create the fault where the machine does not run, and you still measured mains voltage on the pump? This is important because if I understand your post correctly, the machine runs fine cold but does not work when it is hot. If this is what you did, then there is a very high probability that it's the pump. There is a remote possibility that it could be something downstream of the pump, such as the boiler filling solenoid. You can test for this by heating the machine to the point where it does not work, removing the pump outlet hose (temporarily install another hose and aiming it into a bottle), and then creating a condition to cause the machine to autofill. Alternatively, if you are used to dealing with mains voltage, you can disconnect the pump wires and connect the mains directly to the pump. If the pump is running and generating flow (you can judge by measuring the no-load flow and comparing it to the ULKA table for your pump model), and if it is generating pressure (you can put your finger over the end and try to stop the flow...you should not be able to). Having confirmed that the pump is bad, then replace it. But if the pump is working, then we can talk about testing the solenoid.

I have never owned a Strega, so I hope that some Strega owners will jump in here and tell me if I'm off base!

I've had my Strega for over 10 years and have just experienced the same thing.

I found that my boiler filling solenoid was corroded and started to malfunction due to a small leak that developed at the base of the valve.

I replaced the solenoid and I'm not experiencing the issue any longer.

I will go in later to replace the leaky valve though because that is the ultimately the root issue that needs to be attended to.

Update:

I connected the water pump to the hose and then connected the hose to the bottle. However, I found that I could not reproduce the error no matter how long the machine was on, when I left the case off.
I decided to use the "ulka pump" instead of "strega pump" to do a search and found a lot of similar heat related problems.
like here:
Ulka pump problem
So, even though I couldn't pinpoint the cause to the pump, I decided to replace it.
After changing the pump, the problem disappeared.