Mastertemp 400 - temperature reading is erratic

[meepool]

I've found that the reading from the built-in temp probe on the Mastertemp is fluctuating over time. Generally it reads as too low (water will be 80 deg and it reads at 66 deg). However, it's non-deterministic - sometimes it reads the temperature correctly.

I've replaced it with a new Pentair brand probe. The issue persists. Thoughts on the possible issue that would cause different temperature readings like this?

 

[mknauss]

Is this connected to your Intellitouch? The system uses the temperature from the probe connected to the Intellitouch, not the heater, to operate via the Firemans Switch.

 

[meepool]

Is this connected to your Intellitouch? The system uses the temperature from the probe connected to the Intellitouch, not the heater, to operate via the Firemans Switch.

Yes - and to your point, the temp probe on the Intellitouch is malfunctioning AFAICT (can't see a reading from it on the Intellitouch - reference other thread). Seems like I should disconnect the automation from the Intellitouch until I get that fixed. Appreciate the pointer!