This is a good start by Bob but it doesn’t fully address all situations.
I got my hands on an Anova hand me down from someone and was having a constant beep issue and it wouldn’t start BUT it was not a low water sensor issue.
You should be fairly familiar with electronics before proceeding to do this. This is what I’ve worked out. . .
There are 3 temperature sensors on the Anova. Ideally before proceeding, you’ll want to measure each of the temperature terminals on the PCB to figure out which is reading “high”
2 sensors are possibly used to measure temperature and its variance while in operation (the long probe and shorter probe not connected to the heating element).
These two probes coupled together are also used to detect when there’s low water. The resistance between the two probes determines if water is present. One of the wires of the temperature sensor is common to the metal surface (for both of the probes). When water touches the two probes, the resistance is lowered. Soldering a 10k ohm as Bob suggested basically fools the probe into thinking that water is present. I would suggest using a high grit sandpaper to sand the surface of the metal probes before soldering a 10k ohm across as suggested in the tutorial. There is possibly some sort of build up causing the resistance to read high even when water is present. (This suggested fix of course assumes that the two temperature sensors are still working fine).
The third temperature sensor is the tricky one. This is the one tied to the heating element. Mine was reading some really high value on the PCB (something in the mega-Ohms). Temporarily, I bypassed this with a 1k Ohm resistor on the PCB and the Anova worked again. No more beeps.
Next, I proceeded to extract the temperature probe from the metal shell, I noticed that the probe was disintegrated and smelled burned. I managed to work out that this third probe is some sort of safety PTC. The PTC chip was basically almost all black. I managed to measure around 1.1kOhm across the pad. I suspect that the heat from the heating element basically burned out the connection causing the probe to lose connection to the PCB. I’m not 100% but I do believe this would be a 1.1kOhm PTC (which goes into high resistance when it is heated). Functionally, it would cause the heating element to a safety shut-off in the event that the other two temperature probes fail.
In other words, if your Anova is beeping, it could be 1 of 2 issues:
- As Bob mentions above with the low water sensor issue (which I think could be fixed by sanding the metal shell)
- The PTC is for the heating element is burned out (which will require replacement). You should never run this bypassed because then the heating element itself would have no fall-back safety whatsoever.
Hopefully this helps someone else.