Vaillant experts in the house? Struggling to understand HC behavior

Begonnen von strobistar, 13 Dezember 2021, 19:42:16

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Hi there!

Happy camper with an ebusd controller on a PI, with a system with: 1 BAI (VCW), 1 VMD (aurostep), 1 VR70, 1 VRC700 and 1 VRC91.

The VMD is ONLY used to "pre-heat" sanitary warm water, not for the CV circuits. All are floor heating circuits (low temperature). We had lots of (technical) issues with the solar thing, but thanks to ebusd those were discovered and solved.

But now I'm inspecting all data coming in from my floor heating system: there are 2 floors in the house: level 0 (with its own valve) and level 1 (also own valve). In the VR70, level 0 is zone 2 and level 1 is zone 1. But that's a naming thingy. Level 0 carries the VRC700, level 1 carries the VRC91. Aside from the ebusd, I got, for each of my floor heating loops on each floor DS18B20's to measure temperature (for water calibration purposes). All connected to grafana for visualisations.

In the VR70, schematic 1 with address 5 is choosen, which gives me 2 HeatingCircuits and 2 zones. Zone 2 assigned for VRC700, Zone 1 for VRC91. So far so good.

Now the "funny" things:
- If I program on the VRC700 the temperatures for level 0 and level 1, they are NOT shown on the display of the VRC700 (eg: "wanted heating 19°" is shown although I had put 23° as a test), however if I readout the z1DayTemp value, it does stipulate the 23°). So I *think* the brain gets the instructions well, but the display is not following.
- however, If I look closely at my readouts of the DS18B20's, and the following parameters: extWP, Flame and z1ValveStatus, I get the following diagram (see attachment ebusd.png):
---> at 10:50, extWP became on (blue background)
---> hot water left the bai, and warmed up the floor.
---> yellow line = roomTemp and it raises, but nothing far close to 23°C
---> at 14:56, extWP stops. and my DS18B20's are cooling down.
---> at *exactly* 15:10, extWP boops up, for *exactly* 5 minutes. (small peak) in DS18B20's, but room temp is not impressed
---> at *exactly* 15:40, the same process repeats again and again.
---> z1ValveStatus remained 1 all the time, this doesn't flipflop like the extWP.
---> Mc1FlowTempDesired also shows the request for warm water, however it's not given: on;25.0;on;20

What I thought this could be:
- antifrost process? But that's not turned on (and outside temp is around 10'sh)
- interference with the VRC91? As that one is in sleeping quarters, there the desired temp is 19°C. From the manual, I found that if you put "adaptive heating curve" on in the VRC700, it looks at the behavior of the remote (VRC91) to calculate the heat requirement for the VRC700. But I already turned off that "adaptive heating curve", which means that the VRC91 should not (try to) influence the VRC91.

If I don't understand what is causing this, it does not make any sense to me trying to "automate"/"program" the heating myself as it is already "unpredictable" right now to me.

Anyone can shed some light on this? Are there any corners I should look into?

Vielen Dank!


A new finding on my system: yesterday: unexpectedly lots of sun, meaning the ground floot got heated up quite fast. Unfortunately the floor heating did assist in the morning, but the RoomTemp went above 21°C. And that cyclic 30' extWP symptom did not appear!

Hence it is effectively linked to the fact that the VRC700 does want to heat the floor, however "something" is blocking it from doing it.

But what?!

Any insights?

Vielen Dank!