{"pageUrl":"https://www.vheatc.site/why-wont-my-vaillant-heat-pump-cool","title":"Why won't my Vaillant heat pump cool?","lastModified":"2026-05-22","claims":[{"id":"resistor-required","statement":"A Vaillant heat pump runs in heating and hot-water mode only unless the cooling coding resistor is fitted.","source":"Vaillant installer documentation for aroTHERM cooling","hash":"sha256:2b59e85eeb4f497008b2ca7129b019f087e03d4f4b4a423d8f3ffdb7b0cdd897"},{"id":"installer-enable","statement":"After the resistor is fitted, an installer must enable the cooling function in the installer menu before cooling will operate.","source":"Vaillant installer documentation","hash":"sha256:bc21605dabd0160fcb272d84f147445fb6a22c398e0a2a93b45302c58be94535"},{"id":"parts-interchangeable","statement":"Vaillant cooling resistor part numbers 0020266328 and 0020269259 are functionally identical and interchangeable.","source":"Vaillant spare-parts references","hash":"sha256:985522a316a3f54234d0ed8f77c4657dc34f3f1af4230d33a3516645371df441"}]}