Breville Express BES840CB pump problem

#1: Post by **fourrunner** » February 16th, 2023, 6:57 pm

I recently was given a Breville Express BES840CB. When I plug it in to mains power the pump immediately starts pumping water before the power button is pressed. There are no lights on when the machine is doing this. I can press the power button and it lights up, but the pump keeps on pumping. With the Steam/Hot Water Dial on standby the water comes out into the drip tray from the pipe from the defuser, in steam position it comes out the wand and in the hot water it comes out the hot water outlet. Any help would be appreciated is solving the issue.

#2: Post by **bgnome** » February 16th, 2023, 8:45 pm

You have a stuck solenoid. It may work again if you remove it and clean it out, but it will likely need to be replaced.

February 18th, 2023, 5:41 pm

Thanks for your advice. I have tested the solenoid and valves. The valves appear to be working as they should, however the solenoids are buzzing and not activating the valves so it looks like replacements are required.

March 16th, 2023, 12:39 am

Just replaced with a new solenoid/valve assembly and doing the same thing ie. when I plug it in to mains power the pump immediately starts pumping water before the power button is pressed. I can feel that the tank is heating up, the selector control on the side of the machine selects correctly. Is there a reset sequence for the machine or is there an issue with the computer board or something else.
Your advice would be appreciated.

#5: Post by **JRising** » March 16th, 2023, 10:15 am

I would assume your powerboard has been soaked in the past by a leaky boiler fitting (or mis-handling). The board would likely need to be replaced unless your electronics cleaning and component soldering skills are great.

You could contact Breville to find out what it would cost to fix, whether or not it's worth it would be up to you.

March 17th, 2023, 6:04 am

Hi, when you say powerboard, do you mean the circuit board that is on the inside (looking from the front of the machine), on the LH side that is within the white plastic casing?

#7: Post by **JRising** » March 17th, 2023, 8:04 am

Yes. That is the one I was guessing about, though it could be water damage to another component, if it is running the pump while the machine is off (standby) chances are a short on the powerboard allowing the pump's circuit to stay live. This again is just a guess based on machines in general, not specific to a BES840CB.

March 26th, 2023, 6:14 am

OK. I looked at the circuit board and found the BT136, sensitive gate triac, was corroded. I have never worked on a circuit board before, my soldering skills and understanding of electronics are basic but I thought I would give it a go at replacing this $1.00 part. What could possibly go wrong. Fortunately nothing did and now I have a funtioning Infuser.
Thanks to those who helped with the issue.

#9: Post by **JRising** » March 26th, 2023, 8:46 am

Nice work. You owe yourself a good espresso!
Run it with the top off and check it closely for any leaks when it's all hot and pressurized.

March 27th, 2023, 1:08 am

I did run it with the top off, and low and behold found a leak. The cause was a split O Ring, which I think was a newly purchased item. However I had a spare and now no leaks.
Now I have just to learn how to make a good espresso.