Guides
Vaillant cooling guides
Independent, plain-English guides to cooling on Vaillant heat pumps — what the cooling resistor does, how cooling mode is activated, which models support it, and what a cooling upgrade involves.
- What is a Vaillant cooling resistor?Defines the Vaillant cooling resistor (code plug) — the coding component that authorises a Vaillant aroTHERM or VWL heat pump to run in cooling mode.
- What is active cooling on a heat pump?Explains active cooling — running a heat pump’s refrigerant cycle in reverse to remove heat from a building — and how it differs from heating-only operation.
- What is a Vaillant coding plug?Explains the Vaillant coding plug — a resistor in a connector housing that signals an option, such as cooling, to the heat pump controller.
- Active vs passive cooling on heat pumpsCompares active (compressor) cooling and passive (natural) cooling on heat pumps — how each works, what each needs, and which Vaillant systems support them.
- Vaillant 0020266328 vs 0020269259Compares the two Vaillant cooling-resistor part numbers, 0020266328 and 0020269259, and explains which one you need.
- aroTHERM Plus vs aroTHERM Split for coolingCompares the Vaillant aroTHERM Plus monobloc and aroTHERM Split heat pumps as platforms for active cooling.
- Heat pump cooling vs air conditioningCompares using a reversible heat pump for cooling with installing a separate air-conditioning system.
- How to Enable Cooling Mode on a Vaillant aroTHERM Heat PumpHow to put a Vaillant aroTHERM (aroTHERM Plus) into cooling mode: fit the coding resistor, then enable cooling in the installer menu.
- How to check if your Vaillant heat pump can coolHow to confirm whether your Vaillant heat pump supports active cooling, using the model number and installer manual.
- How to find your Vaillant heat pump model numberWhere to find the model and serial number on a Vaillant heat pump, and how to read the VWL / VWF designation.
- How a Vaillant cooling resistor is fittedAn overview of how the Vaillant cooling resistor is fitted into a heat pump’s wiring — an installer task, explained for owners.
- Which Vaillant heat pumps need a cooling resistor?The Vaillant aroTHERM Plus, aroTHERM Split, legacy aroTHERM and flexoTHERM / flexoCOMPACT models that use a cooling resistor for active cooling.
- Will a heat pump cool through radiators?Why standard radiators are not an effective way to deliver cooling from a heat pump, and what to use instead.
- Does the Vaillant aroTHERM Plus Have a Cooling Mode as Standard?Whether the Vaillant aroTHERM Plus has cooling mode out of the box, and what is needed to enable it.
- Is heat pump cooling worth it in the UK?A balanced look at whether enabling active cooling on a UK heat pump is worthwhile, covering comfort, running cost and system requirements.
- Upgrading your heating system for active coolingWhy a standard heating system must be adapted for cooling — fan-coil circuits, condensate handling and controls — not just authorised with a resistor.
- Heat pump cooling and condensation: dew point explainedHow chilled-water cooling can cause condensation, what dew-point control does, and why condensate management matters.
- The cost of adding cooling to a heat pumpThe realistic cost of enabling active cooling on a Vaillant heat pump — the resistor, fan coils, controls and installation.
- Why won't my Vaillant heat pump cool?The common reasons a Vaillant heat pump will not run in cooling mode, from the missing resistor to installer-menu settings and system design.