# Vaillant flexoTHERM Cooling: Do You Need the Cooling Plug?

URL: https://www.vheatc.site/vaillant-flexotherm-cooling
Canonical-URL: https://www.vheatc.site/vaillant-flexotherm-cooling
Updated: 2026-10-20
Language: en-GB

How cooling works on flexoTHERM and flexoCOMPACT ground-source heat pumps, why it differs from aroTHERM Plus, and what to check before buying a cooling plug.

Vaillant flexoTHERM / flexoCOMPACT (ground-source) cooling is set up differently
from aroTHERM Plus (air-source).

- The cooling plug (0020269259 / 0020266328) is listed for aroTHERM Plus only.
- Ground-source cooling can be active or passive, depending on the heat source.
- Vaillant says flexoTHERM cooling with radiator systems is not permitted.
- Check the installer manual or a Vaillant-approved installer before buying.

Buy on eBay (seller boarder895) — the same plug in two packs:
- 0020266328 (Vaillant small-parts bag, labelled with the part number): https://www.vheatc.site/go/ebay/0020266328
- 0020269259 (Original Vaillant box, labelled “Coding plug, cooling function”): https://www.vheatc.site/go/ebay/0020269259