Lelit MaraX steam pressure gauge nonzero when off

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
NebulousWoe

#1: Post by NebulousWoe »

Hi,

I've noticed an issue with my MaraX - when the machine is off, the steam pressure gauge does not return to zero, even after any residual water is released by turning the steam knob:



Attached is how the gauge appears after the machine has been powered off for some time. As you can see the steam pressure reads just above zero - does anyone know why this might be, and what could be done to fix it?

Note that aside from this, nothing is apparently wrong with the steaming function. It steams milk very well. Also, I've had the machine for approximately 1 year and it is probably due to be descaled.

I emailed 1st-Line Equipment's tech support, and received the following response:
The machine will need to be descaled. However, it will need to be overfilled to reach the gauge. After the descaling, we can also learn that the gauge is permanently damaged by the water.

To overfill the boiler, the white wire needs to be removed from the rod on top of the boiler. Machine be cold.
Could anyone help me understand this in more detail? How will the descaling procedure need to be modified from the one prescribed by Lelit?

Thanks in advance,
Zach

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HB
Admin

#2: Post by HB »

That happens when the boiler depressurizes and the vacuum breaker doesn't open. A vacuum forms and pulls the gauge needle against the pin, changing its "zero" location. The vacuum breaker may be sticking due to scale build up, hence 1st-line's recommendation to descale. Descaling won't fix the gauge since the needle was permanently moved. If the gauge can be opened, you could reposition the needle, but often they're sealed. For what it's worth, the gauge is fully functional, you just have to subtract the new "zero point" from the actual reading.

This diagram and discussion from Can someone please explain false pressure? explains how the vacuum formed:



As for descaling, you need to "overfill" the steam boiler by disconnecting the wire to the water level sensor. The pump will then fill the boiler with descaler above the normal water level where scale forms. I haven't read Lelit's specific instructions, but descaling one espresso machine is basically the same as any other (search on how to descale an espresso machine). Assuming you're reasonably handy and follow basic safety rules like "unplug the espresso machine before removing case", you should also check the vacuum breaker is clean and functional.
Dan Kehn
★ Helpful

Pressino

#3: Post by Pressino »

Did the gauge read zero when you bought the machine? It could have been off when it was built...otherwise it got knocked off the zero point as Dan said though there are other ways (like jarring the machine) the needle could have moved off zero. As Dan said it's nothing to worry about...you just subtract about 0.125bar from your gauge reading. You won't be reading steam boiler pressures anywhere near the gauge maximum, so there won't be any problem reading the pressure with this small offset.

NebulousWoe (original poster)

#4: Post by NebulousWoe (original poster) » replying to Pressino »

Thanks for that very informative post, HB! I also found the following exchange on 1st-Line that seemed helpful:


Yes, the gauge definitely read zero when I bought it. Assuming the gauge does not return to zero after "overfilling" the boiler when I descale (and I'm still not entirely sure how to go about that aside from disconnecting the white fill level wire, or what special precautions I should take if any), and that I can't re-zero the gauge otherwise, I could just replace the gauge, right? I'm not sure it's actually worth $55 for a non-functional repair, I just have bad OCD. :lol: