BREVILLE BES 980 – VENTING STEAM FROM WAND, WHEN IT SHOULDN’T

This machine had an obvious issue, see the valve coil in the first photo, its melted. I mention this as its related to the main issue. Which was the machine venting steam from the steam wand, I know this is what its meant to do but I mean it starts venting steam uncontrollably as soon as the steam boiler develops pressure. But this problem only became apparent once I had replaced the melted steam valve and coil.

Obviously the valve was being supplied voltage when it shouldn’t.

Burnt coil on the steam valve solenoid

My first suspect was the switching mechanism. I suspected the switch primarily, for no reason other than they look cheap. And as it turned out this was not a very good reason to look here first. But the switch module may have been a factor as if a switch had been shorting it may have been triggering the micro to open the valve. As picture 3 shows the switches are cheap and the mechanical actuator could cause this issue.

Location of the steam controller unit
Pic 3- Controller module for the steam functions

I tested the switches in the module and on the wand, on my scope and they all were working normally. So I now did what I should have done first up, I tested for voltage at the solenoid when the machine was activated. In my defence I could not hear the valve opening when the machine was turned on so I did not suspect this to be the case. But using the old light bulb trick I soon confirmed the valve was being constantly supplied with voltage. This is not normal and will of course lead to steam venting from the wand.

An old incandescent light bulb connected to the steam valve harness demonstrates a continuous 240V is being supplied to the valve

The controlling component that switches the voltage to the solenoid coil is a transistor TA-8 located on the triac board which is attached to the lid of the machine. Now I was in no mood to pull the entire triac board out and replace it as it takes time so I took a chance and replaced the transistor directly in the board while it was still connected to the machine. I do this a lot and it saves time.
I checked the transister using my curve tracer and I could see a short, so I was confident this would solve my issue.

TA-8
TA-8 Removed and ready for the replacement

Finally, you may want to know the Transistor specifications, I will list these here later and we will have them for sale here very soon. And yes replacing the transistor took care of the issue and yes it was a lot easier than replacing the entire Triac board and far less expensive. So I’m assuming if you have a 980 venting steam from the wand you are right now very happy as you have the solution or now resigned to taking it to the repair shop. Which ever it is, get your triac board or transistor here right now, don’t pay too much for it elsewhere.

Tools required, all the usual stuff but you will need a solder sucker and a soldering iron. Unless you purchase the Triac board.

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