Hi, I have since yesterday a steam overpressure issue with my Mara X. The steam goes way beyond 3 bars during warm-up and the safety valve kicks in. The machine is not usable in those conditions so I had to switch it off and start doing some troubleshooting. As far as I read across the internet, a faulty temperature probe (the one fitted on top of the boiler) may be the cause. I have probed the connector of the temperature sensor with a multimeter and I just read a very bog resistance. I have to move the scale to Megaohms to start reading a 0.4. This looks too much resistance to me for a temperature probe what do you think? It is not an open circuit but not so far from it.

@"repetto74"#p72100 The best bet is to replace the temperature probe.

Thanks DavecUK. Indeed, it should be one of the main causes although this could be also due to a faulty SSR or worst a bad Gicar board. Last two are more pricy :-). I heard also that the probe may not work properly due to corrosion on it. I will start by giving a clean to it and if no changes moving on and replace with a new. I have also checked the SSR relay at least how it behaves. The relay looks different compared to the spare part available with the same Lelit code 9600028. It is black with only on red led lighting up when the machine is turned on. The spare part is a white SSR with a green led lighting on a few seconds after the machine is turned on. The red light on shows that the relay has turned on the heating element but the light stays on all the time. Is the relay supposed to cut the heating element at some point to regulate temperature ?(red light off). Thanks.

@"repetto74"#p72107 If the SSR has failed closed, the boiler will simply overheat…if it's failed open, it won't heat at all. However, if the SSR is getting the message to keep heating…it will do so and may not have failed.

Totally agree :-). Probe may be faulty, the SSR may be faulty in closed position or both may be faulty. I will start with temperature probe cleaning and see what happens :-).

@"repetto74"#p72125 Just make sure it's being tested correctly

Lelit Mara X PL62X steam overpressure

repetto74

I have some news.

I unmounted the steam temp probe. It looked just brand new. I probed the connector and measured a steady 65k resistance. Then I asked someone in the house to keep the probe in the palm of his hand while probing with the multimeter and the resistance went slowly down to 50k. This makes me conclude that the temperature probe is not the issue unfortunately. I cleaned and brushed the probe anyway, mounted it back and confirmed that the issue is not fixed with a test and steam pressure rising up above 3 bars.

During the test I unmounted the bracket where the SSR is sitting to have a clear view on the led.

Here is some pics taken with the steam pressure at 0.5, then 1.5 and finally 2.5. The red light goes on as I turn on the main power switch. I do measure 12V DC on one side and 12V AC on the other.

I am surprised anyway by not seing this led turning off to indicate that the heating element has been cut. On a Lelit video here we can clearly see how the relay is supposed to work:

The SSR in the video is a little bit different but the green light turns on around 5 seconds after pushing the power button. The SSR red light on my machine immediately turns on on power and stays on all the time which seems a bit suspicious.

Coming back to the temp probe, I do not have the light fault combinations to indicate that the probe is faulty or disconnected so I consider this item as good and working.

I decided to disconnect the SSR Relay and probe it out of circuit. On the 12v DC side I measure OL so open circuit and on the 12V AC side I have continuity. This is odd as a good relay should measure Megaohms or no continuity on the AC side when not powered. It is like this relay is stuck open. I may have the culprit here :-).

I may at this stage try my luck and order a replacement relay?

DavecUK

repetto74 Just make sure it’s being tested correctly

repetto74

I followed a guide on youtube to test those SSR. No way there should be continuity on the two pins of the AC side when not powered from the DC side :-).I should read OL on the multimeter while here I have a nice beeper sounding! It is indeed stuck in the open position so it will just say to the heater to stay on continuously.

DavecUK

repetto74 As you can source any suitable decent quality SSR, probably cheaper than an “espresso machine” one, should be a reasonably priced fix.

repetto74

For this one I will go with the original part. I am not very confident to search myself for an equivalent SSR with same specs just to save a few bucks. Hope this will be the one and only fault on this machine :-). Also spare SSRs are from a different brand so maybe those will be more reliable than this black one.

repetto74

I am getting mad trying to find the proper tool to remove both nuts keeping the relay attached to the heatsink. Cannot find any hex nut driver who can fit in the hole and grab the nut.

DavecUK

repetto74 Turn it over and photograph it

repetto74

On the other side the screw is riveted. Only possible way is to find the proper tool that can get through this U shaped hole on the relay and remove the nut.

repetto74

The hex nut is a 7mm but it needs a tool that has a thin profile in order to get into the hole. I think I found it on Amazon.

DavecUK

repetto74 The hex nut is a 7mm but it needs a tool that has a thin profile in order to get into the hole. I think I found it on Amazon.

Yes, I have various thin sockets that would fit..although I just think a deep socket set will do, I don’t think you need specialized thin wall stuff.

repetto74

I finally received the replacement SSR. Format factor is a little bit smaller than the original black one. I have probed pin 1 and 2 of this new SSR and there is no continuity compared to the assumed faulty one.

I can safely confirm now that the SSR has failed in the closed position.

DavecUK

repetto74 The Gavazzi is a very good SSR indeed ACS use Gavazzi ultra hi speed proportional SSR (in the Falcon I) and genuine Crydom in other machines..

fl13dl1c3

repetto74 Interesting, my Mara X purchased in 2021 has the Carlo Gavazzi SSR, not your black colored one. I saw a video on youtube from a Lelit reseller in the US say that the Mara X’s over the past year or so have been shipped with the black SSR that you have and that those have been failing at a high rate.

I have been having heating issues with my Mara X as well. After addressing the temperature probes and Gicar, I suspect my SSR failed as well. I have a replacement coming soon and can confirm after swapping in the new one.

repetto74

Well that didn’t do the trick unfortunately. I still get the SSR power light permanently on with this new SSR replacement and of course steam overpressure when constantly heating.

I probed the new SSR out of circuit and I do not have a connection between pins 1 and 2 compared to the original black relay. Quiet puzzling here, I probably have multiple faults. Original SSR is busted but the PID control box may be also at fault. With a good SSR I should NOT get the power light immediately ON as I turn on the machine. PID is sending constantly the 12V to drive the relay ON. Damned.

DavecUK

repetto74 I think, change the temperature probe as I suggested before.

repetto74

Well it could be indeed the temperature probe but when I probed it out of the boiler it looked totally fine. I had a resistance of 60k and this resistance was decreasing when the sensor was heated in the palm of the hand. I really could not identify any issue there.

Also the fact that the relay is powered as soon as I turn on the machine let me think that the temp sensor has nothing to do here but this is a PID fault (keeps piloting the SSR and turn it ON constantly).

The original SSR may have fried when the PID failed and kept it ON for a long time. Those relay just get burning hot when powered.

Any part here is not just a few bucks. Better at this stage if I gave this to a technician who can point to the faultly components. The new SSR I have it so this one will not be in the replacement parts list.

repetto74

I took my chance and ordered the Gicar PID control box.

Replaced the box and now the Mara X is running again like a charm. No more steam overpressure.

I had a double fault then. The PID control failed and kept the relay ON for a long time which has probably killed it also due to extreme heat pulled out by those SSRs.

Very disappointed on the quality of the electronic. This machine is just 8 month old, still under warranty but shipping costs to the repair center is just prohibitive and far above what I paid for those spare parts.

I will ask anyway to the seller if I can have the warranty cover at least for what I paid in parts :-)

Thanks again for your help!

DavecUK

I did suspect the Gicar Box, but it’s a much more expensive item…

repetto74

fl13dl1c3 you can test the SSR pretty easily with a multimeter. If you probe pins 1 and 2 you should read a high resistance in megaohms and same for pins 3 and 4. If you have a continuity/very low resistance between 1 and 2 or 3 and 4 then the SSR is busted.