ACS Vesuvius steam boiler overheats and relieve valve opens

John_Yossarian

Hello All,

Today my wife expressed her wish to have a cappuccino, which I gladly started preparing. I use my V 99% of the time to make double ristretto shots, and a few times a year I would switch the steam boiler on to froth some milk.

I have had the machine since February 2020 and it has been seamless by far. Today after the boiler heated up to 127 deg I decided to renew the water inside. I poured out around a litre of hot water, the pump kicked in and refilled it. When it started re-heating all of a sudden the display showed 2.7 bar and the red Alarm sign popped up (as shown in the picture) and I managed to switch off the boiler from the touch screen. Just before the screen went all red I heard some steam leaving the boiler, as I suspect, from the relieve valve.
I waited ten minutes and switched on the steam boiler again. Again, the temperature was raising steadily to 121 deg C when once again the display turned red and I had to switch it off.

My thoughts are (I have not yet opened the machine as it is still very hot) that the thermal probe (PID?) has gone wrong and it did not switch off the heating element letting the temperature to raise above the limit and cause the relieve valve to open. I do remember that quite a few users had to replace their thermal probes so I believe my boiler suffered similar fate.

I will very much appreciate your thoughts. I hope that @DavecUK could advise me on the best way of action.

For the time being I will continue using the machine in brew mode, as I have been doing for almost three years now.

I, however, would like to resolve the issue in due time.

Thank you in advance for your wisdom .

Cheers,
John

Cuprajake

Will be the steam boiler sensor. I had to replace one in my evo, luckily really easy to do with PTFE tape

John_Yossarian

Cuprajake Thanks Jake, are these standard or do I have to go back to Paolo and get it from Naples?

DavecUK

John_Yossarian They are standard, if you can get the stainless steel one, they are potted differently and last a lot longer. I guess you could ask the factory, but the postage cost iis likely to be high unless they can fit it in a sort of letter. Also check the probes by swapping the connectors over….. from the brew boiler one, leave the brew boiler one unconnected, or connect it and to not get an error disconnect the heater.

The connectors are about 15cm down the probe wires and can simple be pulled apart and swapped over in a few seconds…then you will know for sure if it’s the probe. If you start up the steam boiler and it all works normally…then your sure.

If you do decide to order a steel one from the factory and the price is reasonable…buy 2!!!

In fact I think it will be cheaper getting it snail post from ACS (they can mark it no value warranty spare. This is because prices are a very expensive in the UK, the brass ones are £30 and this is well

https://espresso-solutions.co.uk/temperature-probe-expobar/

Cuprajake

Not sure, I think there ¼″ but would have to check

John_Yossarian

Cuprajake Did you source it locally or (being under warranty) did Paolo send you a spare? As @DavecUK advised I will most likely go back to Paolo and pay for two just in case, subject of proving the hypothesis (very likely) this is the culprit. Looking at the prices in the UK they are insane.

John_Yossarian

DavecUK "#p37799 Hi Dave, Thank you very much!
I will try to check as suggested and should it be the culprit wil go back to Paolo and ask for two steel probes as advised.

I will update with my findings.

John_Yossarian

Something went wrong whence the double posting. I cannot delete it myself.

DavecUK

John_Yossarian Something went wrong whence the double posting. I cannot delete it myself.

I deleted it for you.

John_Yossarian

DavecUK Hi Dave, I was trying to find the video on the Vesuvius, but it is not on your You Tube channel. I have seen some reviews of Chris Coffee and Whole Lotta Latte but I cannot find yours.

Can you please, post the link?

Thanks!

PS I found a steel Expobar thermal probe for £43 delivered. Is this a good price to consider?

DavecUK

John_Yossarian Check with the factory, they might be cheaper for the steel probe, even posted from Italy!!

Which video are you looking for, it might be linked to in the actual review, and unlisted on the channel?

John_Yossarian

DavecUK I wanted to have a look at removing the top cover and the boiler’s connections. No problem if it didn’t exist. I have noticed that the latest machines have been exhaustively documented, the V was a bit earlier and it might not be there.
I dropped the factory (copied Paolo) an email last night and am waiting to hear from them.

Thanks!

John_Yossarian

@DavecUK Hi Dave,

I have just checked with Bella Barista, they have got the Expobar thermal probe at £29.99 but it is brass as you mentioned. I suspect the steel ones are hitting the ceiling.

Are the original thermal probes on the Vesuvius brass or steel ones?

DavecUK

John_Yossarian Original probes are the brass ones…

John_Yossarian

DavecUK There is no point installing another brass probe instead of the faulty one.

I am still waiting. How quickly do they reply? I might try to call them 😀

EDIT: I called them and spoke to a very kind lady. She asked me to share my details so they can calculate the DHL price. I do not know what to expect, but let’s see.

DavecUK

John_Yossarian The stainless is way better….ACS are moving to it as the standard probe.

John_Yossarian

I brief update. After I ordered and received stainless steel thermal probe from ACS, today I replaced the old brass one, please see the pictures below.
After replacing the faulty one with richly PTFE covered new probe I started the machine with both boilers on.
The steam boiler reached 127 deg C (1.5 bars) and the heating element was switched off by the PID control.

As I live in a soft water region and I also have got an in-line ion exchange resin I wonder what the black thing is that covers the probe. After being in 10% citric acid solution for 5 minutes the probe was cleaned (and ready to go?).

The irony is that over three yeasr I have switched on the steam boiler less than ten times for half an hour each time.

Does the colour prompt for descaling? I have always considered the limestone to be white-ish. I took a picture from our kettle, that is heavily used (since 2009) and never has it been descaled.

I will appreciate your input.

Cheers.

DavecUK

John_Yossarian Black colour is quite normal in soft water.

John_Yossarian

DavecUK Can the stuff on the probe be the culprit, by reducing the heat transfer?
I wonder whether cleaning the probe would do any good?
I also considered replacing the brewing boiler probe but decided to go with “if ain’t broken do no fix it”.

DavecUK

John_Yossarian No the black deposit isn’t the problem. ACS believe the commonly used brass temp sensors potting expands/contracts on heating, and breaks wire inside. They changed to a stainless sensor with different potting, to avoid the problem.

John_Yossarian

DavecUK Thank you for explaining it. It makes perfect sense, moreover the temperature jumps in the steaming boiler are significantly bigger than for the brewing one.