Fixing a Breville BES920 steam boiler issues (descale -> 'vALv' error + burnt probe?)

[artman]

In my friends machine the steam boiler was empty because the probes were giving a false full reading after the descale.

Luckily the thermal fuse did it’s job and blew before the element. It’s s bit painful to replace but not really that bad.

Cheers

[pcrussell50]

I don't descale, ever. Because I use scale free water. But about every month or so, I drain my steam boiler just to reduce the buildup of minerals (of the non-scale kind). Once not so long ago, I did this, and the fill pump just kept running and running and didn't stop. I began to think the boiler wasn't filling. And I was right. I unplugged the machine and open the boiler drain and nothing came out. So I opened the top of the machine and tapped around the vacuum breaker at the top of the steam boiler, closed the boiler drain again, plugged the machine in and this time the boiler filled and all was normal again.

Not sure how much of this applies to you/OP, but maybe before you tackle this big job, open your steam boiler drain and see if there is water in it. If so then maybe continue with your repair. But if not, then you need to figure out why. And hope that the heater didn't try to come on, and then melt the thermal fuse. You can replace the thermal fuse, but it also requires big disassembly, IMS.

-Peter

[artman]

I did a quick write up doing this a month or so ago. Fairly easy, a couple of tricks which I wrote. It was in the other thread.

Cheers

[yojabbajabba]

I got around to pulling the machine apart this afternoon and had a mild panic attack just looking at how much work it's going to be! I'm going to have to take this slow as getting to the fuse will require uplugging all the probes, and accessing the CPU. Not a two hour task that I thought it was going to be! Will update again when I've had a chance to calm down and think of a logical plan of attack - I'm not giving up!

[bigfella]

Any success?

[yojabbajabba]

Any progress mate???

Doing the install tomorrow of a replacement NTC and steam boiler fuse. Wish me luck!

[bigfella]

So it turns out that this NTC probe is key for managing the temperature in the boiler, and so if mine is kaput then that might be part of the issue

Any progress mate???

[yojabbajabba]

Can someone tell me what an NTC probe does?

So it turns out that this NTC probe is key for managing the temperature in the boiler, and so if mine is kaput then that might be part of the issue

[yojabbajabba]

So, I did some digging and that probe is the NTC probe (5.19)
BREVILLE Espresso Coffee BES920 ntc wires for steam boiler | BigWarehouse Spares
Hopefully replacing this does some good, as a new one looks nothing like this dodgy one.

Can someone tell me what an NTC probe does?

[yojabbajabba]

In my experience the valv error, the three beeps on start up and the steam boiler not heating can all be solved by closing the steam knob on the right hand side of the machine. If the machine senses the steam valve is open it knows it's a fool's errand to try and heat water past 100°C. Don't know about the probe.

Hey Ninja,
Tried the the steam wand open / closed when turning on and nothing happened

[level3ninja]

In my experience the valv error, the three beeps on start up and the steam boiler not heating can all be solved by closing the steam knob on the right hand side of the machine. If the machine senses the steam valve is open it knows it's a fool's errand to try and heat water past 100°C. Don't know about the probe.

[yojabbajabba]

HI CS family,

I have picked up this second-hand Breville BES920 (serial 1438-005204-ANZ) in the hopes of giving it some TLC and brewing tasty espressos.
The only issue machine had was as follows:
- steam would leak into the drip tray from inside the machine (leak in the steam boiler)

First thing I thought to do was to do a descale as I didn't know how often the machine had been used... and I got into the trusty 'vALv' error on the second cycle (water flush) of the descale.

I tried several things that I gleaned from the CS forums, namely:
- Following the Breville ANZ instructions for descaling the machine
- Letting the boilers drain overnight
- Tilting the machine to get extra fluids out...
all to no avail.

Further, when I exit the descale cycle the steam boiler isn't firing up / three beep error.

I had purchased a BES9XX o-ring kit from eBay and decided to go inside and replace the o-rings / inspect the valves. Upon inspection, I found the (attached) probe all gunked up. The black stuff looks like melted plastic, and it was on the clip and on the probe. After cleaning this up and replacing all of the O-rings I've fired up the machine and still getting the three-beep error, and can't get past the 'vALv' error. Further, the steam boiler isn't heating up anymore (I felt the right-hand side of the chassis and it isn't warm at all).

Brains trust - here are my questions:
1) Based on the pictures provided, what probe has gone all foul and "black"?
2) Any other options for getting past the vALv error?
3) Any suggestions on diagnosing why the steam boiler is not firing up again.


Thanks in advance!
Y2J