AND/IF/OR/ Logic with Inihibit

Hi everyone,

I was wondering if someone could think of a way to bring the following logic into the core of Velbus (without a computer)… in short… if its really hot outside - I want my internal AC’s to boost their cooling using the built in “booster” channel … so this is independent on the actual internal temperature of a room…
When PIRO provides HIGH alarm (say >40C) I want my AC’s to boost… which would be a regular logic of

PIRO High Alarm == 40
PIRO alarm → Y2 (booster) — Inhibit while open
Thermostat Cool → Y2 (follow)

however, this could create a situation where Y2 does not shutdown again… given;

  1. temp == 41C (inhibit on Y2 removed)
  2. Cooling is activated at one point
  3. Y2 follows Y1 because of 41C condition
  4. temp <40C (inhibit activated on Y2)
  5. AC switches off
  6. Inhibit is activated on Y2 and continues to cool

In short - I would need a command stating… if Cooling is OPEN - Always send OFF to the Y2 even if inhibit is active

I could cancel the inhibit - but that would be counteractive as the next cycle for the AC would then automatically kick in Y2…

could this be where I can send a forced off when Cooling is OPEN ? (0808 action)

Which brings me to the next logic action…
if the room itself is really warm and needs to be cooled quickly (say 4C temperature drop desired) I do want the booster to become active (I do this today with one of the Alarm temperature offsets in the thermostat) - canceling the inhibit…
I could state cancel inhibit while ALARM X is closed - BUT … how would that work in terms of priority of commands…

say alarm X sends the following signals to my Y2 channel…

  • Cancel Inhibit
  • Follow

Would that actually work without a delay timer in between?

Or better to just send a Forced On while Initiator is Closed (0802)


Would you not be better off getting your outdoor PIR to put the room thermostat into cooling Comfort “while initiator is closed” ?

Then for your second part

Use the Boost channel (or other thermostat alarm channels) to do things when the room temp Vs target temp is wildly different?

“Super Boost” if you like

Would you not be better off getting your outdoor PIR to put the room thermostat into cooling Comfort “while initiator is closed” ?

I already switch between comfort/night etc based on time and day… the problem we have here is that during summer the heat outside is so intensive that the AC’s need to run at full power to reduce the room temperature… during spring and fall (whatever we have of those) - the AC’s can run normally to cool the house… and obviously using less power and less noise and wind…

I did used to have this (if its hot outside boost) logic in OpenHab, but was wondering if I could build this natively in Velbus

The boost in room temp vs target was not working for me in some situations (they seem to only work in heating mode… not cooling mode [depending on GP / Edge]) - hence the alarm offset temperature option …

Please look again at the Thermostat Alarm channels

I think you can configure these to do what you are looking for

Especially if you set the Cooling Comfort target to something low

yes… those work… but the question is… if I inhibit the Y2 channel - would a forced on work… or can I cancel Inhibit while initiator closed (thermostat ALARM) to ensure Y2 does switch on - under certain conditions… (see flow)