Overpressure when first turn on machine early morning. La marzocco linea pb x. Any solution


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Apr 5, 2024
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Where can i learn more about espresso machine? iany channel or books about machine.
I have issue when machine turn on first early in the morning. The pressure gauge goes up to 15bars before it slowly come down 9 bars. How can i set it not goes to 15 bars. Just want max up to 12 bars? Is it this overpressure valve adjustment?


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When you turn the machine on and the pressure goes up high, what happens if you open the group-head valve and let a little water run though the group-head? Does the pressure drop? And what happens if you open the steam or hot water wand valve(s)? My reason for asking is I think you have something like a vacuum in one of the lines (only in reverse) and you just need to clear it.
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The pressure drop when i let water run through the group head. Steam does not change anything because different boiler. What is something like a vacuum? What is that? How do i clear it?
When you open the valve and water runs through the group head and the pressure drops, does it go back up after you close the valve or does it stay down?
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This happens because the technician of la marzocco came saying they were doing maintenance job even after my warranty expired.
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I asked them to fix, but they keep declining to fix. Saying it is normal. This never happened before on the factory setting when i first got the machine
Do you back flush the machine regularly? Has it ever been descaled?

The simple answer is to open the group head valve and let the water flow for a few seconds when you turn it on. I think it's just left over pressure in the line from the last time it was used and it's certainly not causing any real issues...BUT if it hasn't been back flushed in awhile I would do that AND if it hasn't been descaled I would probably do that too to see if it helps.

Surprised to hear that la marzocco tech won't fix it. You could try writing to la marzocco corp and complain (nicely) and see if that gets attentions. La marzocco isn't a cheap machine and they should repair it.
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I back flush my machine everyday before closing. I have not descale the machine because just bought the machine for 1.5 year.

I need to keep doing it manually everyday so that the pressure goes down?
Are there any other way to fix it. What are the real problems?
La marzocco corp won't respond either. I tried emailed them nicely regarding this matter with no replied.
My first thought is the expansion valve needs to be adjusted. The valve should not allow the boiler to build up that much pressure but if it was the expansion valve when you ran some water through the group head within a few minutes it would build the pressure back up. In any case, I would look into how to adjust the expansion valve and lower its setting. According to La Marzocco's manuals the boiler pressure should never exceed 12 bar. There is a section in the La Marzcco manual on how to adjust the valve.
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Where can i get the manual for la marzocco? I will adjust the expansion valve. I remember reading from forum about 9-12 bar range for the boiler pressure, not to exceed more than that range. That is why i asked them to, but they insisted that it should be on 15 bar when first open. I will try again for the expansion valve.
Now the pressure gauge broken as they make it to 15 bar. I asked for replacement but they asked me to buy even though they came in expired guarantee.
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Thank you for your manuals, very appreciated.
Here in my country, the technician and the company from la marzocco distributor very not good. i had asked the distributor and la marzocco corp to settle the matter. The la marzocco corp do not respond.
i had adjusted the expansion valve just now, but forgot to close the steam valve. I will try again this afternoon.
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I have tried it, turn release the expansion valve. It is 12.2 now, i think it is okay now. it goes up to 12 & stay at 12 when i do not brew. And drop to 8.9 bar when brewing.
However, the pressure gauge has been damaged. Thank you