Expobar Brewtus Steam Overpressure

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

#1: Post by MarRxK »

Hello.

Long-time lurker, first-time poster.

I've had my Office Leva Dual Boiler for 10+ years. Apart from a few LED segments missing on PID display, it has been rock-solid (NB: blank PID segments pre-date the about-to-be-described problem by a few years).

The problem:

Recently, the steam pressure rapidly increases to > 2 Barr within a few minutes of startup. The safety valve opened on the initial incident to release the pressure. The PID still shows low temperature in brew boiler when over-pressure occurs. The steam-boiler heating indicator light appropriately extinguishes at 1.1 Barr but I can still hear what sounds like continuous boiling in the steam boiler even when the light is off and the pressure keeps rising. Releasing water/steam from the hot water want or via the group head relieves the pressure but the water was initially quite discoloured (rust-tinged). After some flushing, the water colour has improved.

I have performed the testing steps in the WLL electronics YouTube video found here:

Expobar intermittent over-pressure, any ideas?

On my multi-meter, with the steam-boiler heating indicator light on, could only get 2V at the pressurestat power input, 120 V to steam boiler and 2V to brew boiler. With the steam-boiler heating indicator light off, I got 2V at pressure stat input 2V to steam boiler and 80V to brew boiler. I replaced pressurestat and had the same issue/readings.

I replaced the high-temperature reset thermostat on steam boiler (the original reset button had disintegrated so I replaced it despite the contacts showing continuity) and still have the same issue.

My next step will be to check the feed tube as per this post:

Expobar boiler pressure goes sky high

However, I am wondering if someone more knowledgeable than I can help me understand if the above voltage readings indicate an electronics problem in the circuit preceding the pressurestat or if the discoloured water offers some other clue.

I really miss my espresso.

Thanks in advance.
Mark

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cafeIKE
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#2: Post by cafeIKE »

If you don't have it,
parts manual and schematic


It's not 100% clear from the your post:
  1. Do you hear the pstat click? If not, then it is shorted closed.
  2. Does the steam boiler heat with the Steam switch off? [I.V.] on p21. If yes, the switch has also failed.

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Sponsored by ECM Manufacture
MarRxK (original poster)

#3: Post by MarRxK (original poster) »

Hello Ian and thank-you for your reply.
  1. Yes, there is an audible click from the pstat that coincides with the steam-boiler heating indicator light going out.
  2. My machine only has one switch to control both boilers so I am unable to test a specific steam switch. All heating (lights/boiling sounds) stop when that switch is in the off position.

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cafeIKE
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#4: Post by cafeIKE »

If you've had the machine since new and have never had it apart, it could be the machine is not wired according to the schematic.

If the brew boiler doesn't heat until the steam boiler, the pstat is working on that pole.

It often helps to remove some of the wire ties that hold the loom together. Be sure to replace when buttoning up.

If you can follow the schematic, with the power off pull off the steam boiler connection to the input side of the thermal safety. Power the machine and if the machine refuses to heat either boiler, circuit looks good up to there. Power off the machine, replace the connector and move to the next connection closer to the steam heating element.

A clip lead connected to neutral [blue in the schematic] and a probe allow to quickly follow the wiring.


MarRxK (original poster)

#5: Post by MarRxK (original poster) »

Hello Ian.

Thank-you once again for your reply. There seems to be something wrong upstream of the safety thermostat/pstat. I removed the steam boiler connection to the input side of the thermal safety as per the wiring diagram and the steam boiler did indeed start to heat. However, the indicator light on the front of the machine did not illuminate as typically happens. After reconnecting the pstat to the thermal safety and powering on again, the steam boiler started to heat and the indicator light illuminated. I'm having trouble following the diagrams back from that point as all of them show a steam switch, which my unit does not have. Any further advice?

Mark

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cafeIKE
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#6: Post by cafeIKE »

Can you post a image of your machine front, and as many of the inside as you think necessary.

Your profile says Expobar Brewtus III, but we are looking at and Office Leva EB

MarRxK (original poster)

#7: Post by MarRxK (original poster) »

Hello Ian.

It's been a busy week. Just getting to posting images now. Indeed the serial plate shows a model of OF-P-1GR (LEVA 1 GR.OFFICE), although the manual that accompanied the machine is for a Brewtus III. My understanding is this is simply a branding difference based on the country but please let me know if I am wrong. Here are a few photos:

Front:


Boilers from the side:


Boilers from the top:


Thanks.
Mark