BREVILLE BES 920 COFFEE BOILER FAILURE – FUSE BLOWN. YOU REPLACED IT, BUT THE MACHINE STILL WONT REACH RUNNING TEMP 93 DEGREES

What the hell is this guy on about? – just wait before you dismiss this rant, does the following sound like you and your machine issue.

Ok you noticed the machine seemed to be getting too hot, then one day it stopped getting hot at all. You got brave enough to open the lid and you noted the coffee boiler was stone cold.

Ok you thought, check the fuse. Sure enough the fuse was blown. So you replaced the fuse, but you remembered what the old Russian Coffee Tech Vidali said all those years ago. “A thermal fuse does its job by blowing, Nyet is it just a fuse at fault”.
Ok you thought it must be the triac board. You noted the amp draw was 0.9A, (as it should be) when the machine was off but you were felling lazy and decided to stuff this job up and assumed the triac board must be at fault. So you ordered one from Outwest Coffee and fitted it and a new thermal fuse for the coffee boiler. And to your horror, the same thing happened.

The machine temp on the display hung at 65 to 70 degrees and very strangely, the coffee boiler was getting way too hot. So to avoid damaging the new fuse you turned it off. You now realized the machine is mental, its not the triac board. Its showing a low temp yet cooking the shit out of the coffee boiler.

So you look on the error log it tells you the coffee boiler is over temp. So this tells you the machine knows its cooking the coffee boiler, but it still does it. Its almost suicidal, now you are scratching your head. It cant be the coffee NTC?, maybe the new triac board is faulty? You just cant let go of that Triac board.
You check the water level in the coffee boiler, its full???

Has this machine lost its mind? – are you in cognitive decline, just like Joe Biden. Are you crap at this like the wife says. No, no there is a logical explanation outside of the square.

Ok – firstly on the newer BES 920s the displayed temp is a function of the Block NTC and the Coffee NTC (an average of the 2) so we know the coffee NTC is probably ok the processor knows it is going over temp. Could the block be going over temp and heating the coffee boiler. Yeah but then why is the block over temp not registering in the Error Logs.

Suddenly the penny drops. If the block NTC has failed it would not register an over temp alarm, nor would it return a normal value to the display temp calculation. And yes the Breville did not think of that. so that temp on the display is probably 5 degrees (faulty block sensor reading), + 105 degrees (real coffee boiler temp reading)/2.

So here is what is going on,

  1. The block NTC has failed, sending a low value to the processor.
  2. The processor is heating the shit out of the block element trying to get it to the set temp, which is over heating the water in the coffee boiler. which sits on top of the block.

    Sure enough replacing the block NTC solved the issue. The only remaining mystery is why did the thermal fuse on the block not blow. Why did the coffee boiler thermal fuse blow first. The answer is, just to screw with you. And the placement of the fuse means it never seems to get that hot.

If I lost you somewhere in there, don’t worry. Buy a Triac board from me. They fail sooner or later anyway. But it it fails to resolve the issue, check your NTC’s. Might be a good idea to replace them anyway. The coffee NYC and the block NTC.

Leave a Reply

%d bloggers like this: