Zone 1 temperature consistent sudden drop when zone is heating

[ericmagaha]

Hello.

I have a water furnace 5 system with 2 zones. It is a new system that was installed in October.
I have been running this software for a few months to view additional data. It works great. I do not use home assistant or MQTT, I just fetch the data I want from whatever registers using aurora_fetch and then parse it and display it on my custom display.

I am fetching zone 1 temperature from register 31_007. I am seeing consistent strange readings when the system is running and zone 1 is calling for heat i.e. h1.

Example:
Zone 1 heating target - 68°F

The zone 1 temperature will gradually increase, and then when it gets to 68.8, it will immediately drop to 68.0 and then work its way back up to 68.5 and then the zone will go into standby. The stage 1 differential is 0.5.

This happens regardless of the target temperature i.e. if the target is 70°F, then the zone 1 temp will go to 70.8, then drop to 70.0, then work its way back up to 70.5 and then go to standby.

I do not see this behavior with Zone 2.

Is there some calculation that the waterfurnace is doing or some other register I should be pulling Zone 1 temperature from?

Thanks.

[ericmagaha]

After staring at the data I see that the register Zone 1 Ambient Temperature (31007): 68.7°F is showing the same data as Entering Air (567): 68.7°F and Entering Air (740): 68.7°F.

And the values track each other identically. I am guessing that there really is not a true Zone 1 Temperature.

Does anyone have any more information related to this?