Expobar Brewtus thermoprobe replacement

[Dogshot]

The probe that is located in the brew boiler of my Brewtus II is giving me faulty readings, and preventing my brew boiler from achieving sufficient temperature to be useful. The photo below shows the probe as it enters the boiler. I'm not sure what it looked like when new, but it appears to have at one time had some kind of insulating caulking on it, which has now disintegrated.




I'm not too keen on removing bolts that are attached directly to the boiler, but do I have any options in this case?

Thanks - Mark

[cafeIKE]

It's not a huge job:
- order the CORRECT part from a vendor. [check the spec if possible]
- get the correct BOX spanner and a small wire brush
- assuming a proper gasket is not supplied, get some teflon valve packing from a hardware store
- unplug the machine and let cool
- do a quick brushing around the sensor to remove any loose bits
- disconnect sensor from control
- remove the sensor with BOX spanner
- put two turns of teflon valve packing around new sensor
- check the boiler threads and sensor seat for old packing, grit, etc. Clean as necessary
- install new sensor, tightening just enough to flatten the packing into a nice gasket
- fire up and check for leaks
- enjoy

[jggall01]

The probe that is located in the brew boiler of my Brewtus II is giving me faulty readings, and preventing my brew boiler from achieving sufficient temperature to be useful.

Hi, Mark -

How do you know it is a faulty probe, as opposed to a faulty controller? (Not challenging, just curious).

Jim

[Dogshot]

I know that it's the probe because I hit the problem with a sledgehammer. Parts are not easy to get in Ontario, so I ordered the component stream, from controller to probe. I then started with the easiest part to replace, which is the controller. New controller, same problem, which leaves me with the probe...

It's not a huge job:
- order the CORRECT part from a vendor. [check the spec if possible]
- get the correct BOX spanner and a small wire brush
- assuming a proper gasket is not supplied, get some teflon valve packing from a hardware store
- unplug the machine and let cool
- do a quick brushing around the sensor to remove any loose bits
- disconnect sensor from control
- remove the sensor with BOX spanner
- put two turns of teflon valve packing around new sensor
- check the boiler threads and sensor seat for old packing, grit, etc. Clean as necessary
- install new sensor, tightening just enough to flatten the packing into a nice gasket
- fire up and check for leaks
- enjoy

Thanks for the notes, Ian. The sensor did not come with a new nut, and I don't understand how the sensor wire travels through the nut while maintaining a seal that holds back 10bar+ pressure. My guess is that I will need some kind of goop to hold the sensor in place to the nut - but what?

Mark

[cafeIKE]

The sensor should come as an assembly

that looks something like the above.

[EricC]

From what i can remember the sensor on the Brewtus is a push fit inside well that you can see the top of, it is not in direct contact with the water in the boiler. The dried up silicone that you can see is just there to hold the sensor in place at the bottom of the well. If you pull on the wiring coming out of the well, the whole lot should just pull out with the sensor on the end.

Regards
Eric

[cafeIKE]

Time for a sensor upgrade

<rant on>
It always amazes me how manufacturers scrimp for the sake of a few pence. My Solis SL-90 had some cheap and no so cheerful heat compound around the thermistor that dried out in short order, sending the machine into Stability->None mode.

A fraction of a penny's worth of a high quality, computer grade, non-drying heat sink compound restored the stability better than new.
</rant off>

[Dogshot]

I cannot fault you on this rant - have had a few of my own over the past couple of hours.

I wound up following both Eric's and Ian's advice. I tried to pull the probe from the housing (nut), which despite being careful with the pulling, broke the probe wire at the base of the nut. Now I guess I will try getting a really thin pair of needle-nose pliers and some liquid wrench to grab what little of the wire remains and pull the probe out. Not sure what to do if that fails.

Since the job was getting finicky, I removed the nut form the boiler, which came out easier than expected. I have been using water that I test regularly with an aquarium tester to ensure less scale, but after 2 years of use, the probe is looking ugly:


This was supposed to be an easy job...

Mark

[mhoy]

Yow, that's worse than my Elektra was. At least you got the probe out, probably took some wiggling. Which by the way dislodged some chunks of calcium into your boiler... you wanted to descale anyway right?

Mark

[TRH]

Mark,

You may be able to get a thin hooked tool past the thermistor and then see if you can pull it out. I remember the thermistor in my Brewtus 1 was smaller in diameter than the well.
Good luck.

[RegulatorJohnson]

i wonder if all the scale was causing the probe to not work well?

jon

[Dogshot]

Well, at least descaling is rewarding...


I siphoned out the brew boiler, since this was a (hopefully) rare opportunity inside the brew boiler, and was surprised to see that what I could see of the boiler sides from the hole looked totally free of scale. My siphon job pulled out a lot of the scale that had fallen off the probe body during its extraction.

I'm confident that scale was not the source of my problem. The controller would give me readings in the 60-80 degree celsius range while the steam boiler was heating, and prior to the brew boiler getting heat. As soon as the brew boiler heater kicked in, in would quickly climb to an over-temp reading. I think that by the time the heat compound on the outside of the sensor body (ie, the nut) hardened and crumbled away, the probe casing failed at the boiler entry, and was responsible for the readings.

My problem now is that pliers, tweezers, and liquid wrench failed to remove the chunk of probe that is stuck in the sensor body. I will get a dental tool from the pharmacy to try to get under the stuck portion of probe and hook it out, as suggested. After that, I guess I will get a drill bit smaller than the diameter of the sensor body, and try to drill it out; after ordering a replacement part from the supplier, of course.

Thanks for the help so far!

Mark

[mhoy]

I wonder if the probes for a different system would work in the Brewtus. The one from my Elektra looks similar but the probe part seem bullet proof, however it's only boiler pressure...

Here it as just after pulling it from my machine.



=-=-
Mark

[cafeIKE]

When you reassemble, be sure to use a top quality, non drying thermal compound.

Also try to get some heat shrink around the probe lead where it exits the well to act as a strain relief.

I don't know how old the machine is, but I'd try to preclude further similar exercises with the purchase of a proper probe sensor that matched the spec of the original. More DoReMi, but a lot more reliable.

[Dogshot]

The temperature probe had melted against the sensor body, so my only option was to drill it out. Fortunately, I had a bit that fit the sensor body perfectly, and so it was very quick, easy, and effective in removing all traces of the offending probe.

I put in the new probe, followed Ian's advice for putting the sensor back into the boiler, and it is leak-free.

My Brewtus II is back up and running after an extended absence (just over a month). I used my PV Export as my full-time replacement, and it performed very well. However, I am so happy to have my Brewtus II back! The espresso is very different from my lever, and I missed my temp controlled 8-bar pump machine. It is also faster to brew and clean up, and of course, I don't have to wait for 10 minutes for the machine to heat up whenever I want a cup. I celebrated with some 49th parallel, and it was like having a port (wine) mousse.

Thanks again for all the help!

Mark