Cooling upgrades for your Vaillant heat pump

Why radiators heat but can't cool

A radiator warms a room from a hot surface, and warm air rises and circulates naturally. Cooling has to work the other way around — and a radiator is the wrong tool for it. Its surface area is far too small to absorb a useful amount of heat from a room, and a cold radiator surface would simply collect condensation and drip.

Effective cooling needs emitters designed for it. The usual answer is a Fan-Coil Cooling Loop — a closed chilled-water circuit feeding fan-coil units that move air across a chilled coil and catch any condensation in a built-in tray. That is why a cooling upgrade is a change to your heating system — not just a part and a setting.

What a cooling upgrade involves

There are three layers to it. The Vaillant cooling plug (sold on eBay as 0020266328, or boxed as 0020269259 — the same plug) puts the heat pump into Authorised Cooling Mode. A Vaillant-approved installer then enables cooling in the heat pump settings. And the heating system itself is adapted — a Fan-Coil Cooling Loop with condensate handling and the right controls. The building-side work to get to that point is what this site calls a Cooling-Ready Retrofit. The guides below walk through each part.

The cooling upgrade, in detail