Entity addition: ZUP Venting

[Carigo77]

Is it possible to integrate a switch to bleed the auxiliary hydraulic pump (ZUP)?
like this:
switch.luxtronik_210502_0111_pump_vent_hup
... only for the zup.

That would be great!

[rhammen]

Thanks for the suggestion. Before building anything I'd like to test this on real hardware, because it's relatively unexplored territory: the venting program selects pumps through a block of parameters ID_Einst_Entl_Typ_0 … _Typ_15, and only _Typ_0 (the HUP, behind the existing pump_vent_hup switch) has ever been exercised. Nothing documents which index is the ZUP. The controller's venting menu and the matching visibility flags both list it second, so by all appearances it's _Typ_1 (parameter 679) — but that's an inference, and a switch that bleeds the wrong pump isn't something I want to ship.

Could you try it manually on your unit?

1. Enable number.…_pump_vent_timer_h if it's disabled (it's off by default) and set it to 1 hour.
2. Run the luxtronik2.write action:

   action: luxtronik2.write
   data:
     parameter: ID_Einst_Entl_Typ_1
     value: 1

3. Turn switch.…_pump_vent_active on right after. On the unit where the HUP switch was first tested, the pump selection was dropped when the start switch didn't follow within a few seconds — whether that also applies here is one of the things worth finding out. If ID_Einst_Entl_Typ_1 reads back as 0 before you got to this step, repeat 2 and 3 more quickly.

Then watch binary_sensor.…_additional_circulation_pump (the ZUP output): it should turn on, while binary_sensor.…_circulation_pump_heating (HUP) stays off. The venting program runs in cycles with pauses, so a short off period during the run is normal. To stop early, turn pump_vent_active off; if _Typ_1 doesn't clear itself afterwards, write 0 back.

If that works as expected we can most likely implement it. A diagnostics download from your unit (Settings → Devices & services → Luxtronik → ⋮ → Download diagnostics) would help too — there's no dump from a 210502-series unit in my collection yet.

[rhammen]

Thanks for testing, and for the quick report! That confirms ID_Einst_Entl_Typ_1 is the ZUP, so it's now available as a switch in pre-release 2026.09.24. To install it in HACS, open Luxtronik → ⋮ → Redownload, pick 2026.09.24, and restart Home Assistant.

After the update:

1. Enable switch.luxtronik_210502_0111_pump_vent_zup under Settings → Entities. It's disabled by default, because I expect this feature will only be used by a (very) small number of users.
2. Venting then works as in your manual test: set pump_vent_timer_h, turn on pump_vent_zup, then pump_vent_active.

The steps are also documented in the new Pump Venting section.

Two things would help while you try it:

• Timing: did you have to turn on pump_vent_active within a few seconds of the ZUP selection, or did pump_vent_zup stay on for a while by itself? On the unit where the HUP switch was first tested, the selection was dropped when the start didn't follow quickly. I've noted that in the docs as a caveat, but I'd like to know whether your unit does the same.
• Diagnostics: the dump you mentioned is still welcome whenever you get to it. It would be the first one from a 210502 unit.

[Carigo77]

As soon as I activate pump_vent_zup, it stays on and the auxiliary circulation pump (ZUP) runs. Then I start the venting program so that the pumps are switched on and off at specific intervals.
I have to do that about minimum

30 seconds later.

P.S.: My Luxtronic system doesn't have a diagnostics function. What kind of data is in the data logger? (.dta files, etc.?)

[rhammen]

Thanks, good to hear the switch works on the pre-release. Your note that pump_vent_zup stays on and the ZUP runs by itself is useful. It means the "start within a few seconds" caveat from the HUP unit doesn't apply to yours, so I'll adjust the docs.

One question about the timing: when you say "minimum 30 seconds later", do you mean you have to wait at least 30 seconds before turning on pump_vent_active (for example, because it doesn't start if you're quicker)? Or is 30 seconds just how long it usually takes you?

About the diagnostics: sorry, I should have been clearer. I didn't mean a function on the Luxtronik controller or its datalogger (.dta files aren't needed). I meant the diagnostics download in Home Assistant:

Settings → Devices & services → Luxtronik → ⋮ (next to your heat pump entry) → Download diagnostics

That gives you a .json file with the parameter and calculation values the integration reads. You can drag it into a reply here.

P.S. Your screenshot didn't upload: the post only shows the "Uploading Datalogger.jpg…" placeholder. If it's still relevant, could you attach it again?

[Carigo77]

Ah, okay—here are the diagnostic data. So, the screenshot is no longer necessary.

By "30 seconds," I meant the time I have to wait before sending the next command to the Luxtronic. When I set ZUP or HUP to "active," the Luxtronic is busy for a moment and doesn't respond for a few seconds. I can then send the next command via Home Assistant about 30 seconds later. (It might be due to VPN latency; my Home Assistant server is running at a different location via a site-to-site VPN.)
config_entry-luxtronik2-01M2N0K1CRWQ6K7XV48W2V744P.json

[rhammen]

Thanks for the dump and for explaining the 30 seconds. I've adjusted the docs to match what you found: on your unit the selection stays on by itself, which is different from the unit where the HUP switch was first tested (#814).

About the delay: this is very likely not your VPN. Your controller runs firmware V1.90.0, and that release has a known bug: after any parameter write, the controller freezes, drops off the network completely, and comes back one to two minutes later with the new value applied. It's documented in #761 and its duplicates #806 and #809 (all closed). It's a firmware bug, and the integration can't work around it: writing over a fresh connection made no difference either.

Your diagnostics show the same pattern. Next to the "busy" controller you described, the log has two "Socket is not connected. Attempting to reconnect..." warnings from today. That's the message the integration logs when the controller has disappeared from the network, and it's what the other V1.90.0 owners saw too. So I'm fairly sure this is the same issue. If you want to confirm it: after a write, does the Luxtronik web interface (or a ping to the controller) stop responding for a while?

The fix that worked in those issues was a firmware downgrade. In #806, a V1.90.0 unit went back to V1.88.3 (installed from a USB stick), and writes have worked without reboots since. Only the newest firmware can be downloaded publicly, so if you don't have an older image yourself, your installer or the manufacturer's support would need to provide it.