In depth
Vaillant Cooling Option Not Showing? What to Check
Missing cooling menu — the usual causes, in order
You have a Vaillant aroTHERM Plus, summer has arrived, and there is no sign of cooling on the controls. On a heat pump supplied without cooling, that is normal. This guide goes through the usual reasons the cooling option is missing, starting with the most common, and what to do about each.
Updated
Buy the Vaillant cooling plug on eBay
Same blue plug, two packs. Choose the boxed 0020269259, or get the identical 0020266328 for a fraction of the price.
Original Vaillant box, labelled “Coding plug, cooling function”
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1 — No cooling plug fitted
On a unit supplied without cooling, the cooling option stays hidden or unavailable until the cooling coding plug is fitted. This is by far the most common reason cooling is missing.
What to do: have an installer fit the plug — Vaillant 0020269259, boxed and labelled “Coding plug, cooling function”, or the identical 0020266328 — and then enable cooling.
2 — Cooling not set up at installer level
Fitting the plug makes cooling available; it does not switch it on. An installer still has to enable cooling and tell the system how it cools.
Owners on the OpenEnergyMonitor community forum describe a setting on the heat pump’s own controller, reached at installer level, called “cooling technology”. They report that it had to be changed from “no cooling” to “active cooling” before cooling would run, even with the plug fitted.
One owner on the same forum reports that, with the plug fitted, cooling only ran when the controller’s cooling test mode (reported as P11) was started, and the system went back to standby when the test ended. That pattern points to cooling being authorised but not yet enabled or scheduled for normal operation — an installer-level setting, not a faulty plug.
3 — An energy-supplier setting blocking cooling
One owner on the same forum traced a heat pump that ignored every cooling request to an installation setting for the energy supply company signal (ESCO), which had been set to “Cooling off”. That setting decides what is switched off when an energy-supplier signal arrives.
What to do: if cooling is enabled but never runs, ask your installer to check the ESCO setting.
4 — The app has not caught up
After cooling has been enabled, owners report the cooling option appearing in the myVaillant app only after closing and reopening it. If the system control shows cooling but the app does not, restart the app before assuming a fault.
5 — The model is not set up for this plug
The cooling plug is listed for the aroTHERM Plus range, VWL 35/6 to VWL 125/6. Other models — particularly ground-source heat pumps — enable cooling differently. Check your model code on the data plate and confirm with a Vaillant-approved installer.
Missing cooling option — symptom, likely cause and what to do.
| Symptom | Likely cause | What to do |
|---|---|---|
| No cooling anywhere in the menus | No cooling plug fitted | Installer fits 0020269259 / 0020266328, then enables cooling |
| Plug fitted, cooling still unavailable | Cooling not set up at installer level | Installer checks the cooling settings |
| Cooling enabled but never runs | An ESCO setting set to block cooling | Installer checks the ESCO setting |
| Shows on the control but not in the app | The app has not refreshed | Close and reopen the app |
| Not an aroTHERM Plus | Cooling enabled differently on this model | Confirm with a Vaillant-approved installer |
Frequently asked questions
I have fitted the plug and cooling is still not in the menu — why?
Fitting the plug makes cooling available but does not switch it on. An installer still has to enable cooling at installer level; owners also report a "cooling technology" setting on the heat pump’s own controller that has to be set to active cooling.
Can I turn cooling on from the app?
Once an installer has enabled cooling, owners report switching it on from the system control or the myVaillant app. Before that, the option is not offered.
Which plug do I need?
The Vaillant cooling coding plug: 0020269259, sold boxed as “Coding plug, cooling function”, or the identical 0020266328 in a Vaillant small-parts bag. It is listed for aroTHERM Plus VWL 35/6 to 125/6.
Related guides
Ready to buy? Both plugs are on eBay
The plug inside is the same — choose the pack. 0020266328 is the best value; 0020269259 comes boxed and labelled “Coding plug, cooling function”.
Original Vaillant box, labelled “Coding plug, cooling function”
Buy on eBaySold by eBay seller boarder895 · 100% positive feedback · 600+ feedback · on eBay since 2003 · 20+ plugs sold
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