# Espresso Machine Pressure Drop



## Scott145 (May 24, 2020)

With a fully warmed up, 4 month old, well maintained Lelit Mara single boiler heat exchanger espresso machine, when I pull the lever to make a shot of espresso, the machine starts pumping and tries to build pressure. But often the machine generates a very audible mechanical "click" at about four bars of pressure (2-4) seconds into the shot) and simultaneously drops pressure to 2-4 bars. The machine will occassionally get past this low pressure mode and get to 9-10 bar for a good shot but usually not. When in this low pressure pumping mode, when the lever is rotated down to stop the process the machine will not shut off and I have to turn off the power switch.


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## DavecUK (Aug 6, 2013)

The click is the autofill solenoid opening and trying to fill the boiler at the same time as your pulling a shot and it's why the pressure drops. The machine doesn't shut off when you move the lever down because it's still filling the boiler (most good prosumer machines run a timed overfill of the boilers to prevent the pump cycling on/off all the time when steaming.

By switching it off, you are cancelling that timed overfill and ensuring a much higher possibility of the autofill coming on during a shot again. Additionally, if you have a little habit of a small water draw from the water wand, enough to warm a cup  but not enough to drive an autofill then your chance of this happening during a shot is increased again.

Doesn't sound like there is anything wrong with the machine.....


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## NewboyUK (Jul 14, 2018)

Can the board be programmed not to fill during a shot? But sounds normal to me as @DavecUK says


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## Scott145 (May 24, 2020)

Davec and Newboy,

Your explanation sounds extremely reasonable to me - thanks. So the best way to prevent this is to not use some hot water to warm the cup before brewing? The other thing that I do is remove the portafilter to add the coffee and just before reinstalling and pulling a shot I would pull the lever to release some "extra" hot water since this is a heat exchanger machine. Maybe the "extra" hot water is Ok since it hits room temp coffee and cools quickly. I haven't tasted any difference in the shots or in the temp of the shots if I do this. Are there any other ways to minimize or prevent the auto refill pressure drop from happening?

It is nice to know that my machine is working properly. The operator is not working properly.

Scott


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## DavecUK (Aug 6, 2013)

NewboyUK said:


> Can the board be programmed not to fill during a shot? But sounds normal to me as @DavecUK says


 In MaraX full shot protection is programmed in a the auto fill is suppressed during a shot.

No way I know of to get Mara non X board programmed by users or retailers


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## Scott145 (May 24, 2020)

Today my boiler stopped filling on my Lelit PL62T.

I pulled shot on my warmed up machine then drew some hot water from the wand. This has always actuated the pump to refill the boiler but not anymore. The pump still actuates when I lift the shot lever however. I tried this quickly as I know the water level in the boiler is low. Turning power on and off did not help.

I don't know what has failed. Is it likely the boiler level probe at the top of the boiler or the electrical connector to it? I have always used pretty soft water and have not descaled the machine in a year.

Any help would be appreciated.

Thanks.

Scott


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