How to check if your Vaillant heat pump can coolFour practical checks before you order a cooling resistor
Cooling is an option on Vaillant heat pumps, not a guaranteed feature — so it is worth confirming your unit can cool before buying parts. There are four practical checks: the model designation, the installer manual, whether a coding resistor is already fitted, and a quick word with a Vaillant-approved installer. This guide explains each one.
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Check 1 — The model designation
Start with the data plate on the unit. Vaillant heat pump model codes begin with VWL for air-source units (the aroTHERM family) and VWF for some ground-source units. The full designation, including the variant, tells you which product family you have.
A cooling-capable family is the first requirement. The model code alone does not always confirm the cooling option, so treat it as the starting point rather than the final answer — confirm with your installer manual or a Vaillant-approved installer.
Check 2 — The installer manual
Your installer manual is the most reliable document you hold. Look for the cooling section and the accessories or coding-plug section. If cooling is listed as an available function or accessory for your model, that is a strong indication the unit can be set up to cool.
If you no longer have the manual, you can usually download it from Vaillant’s website using the exact model designation from the data plate.
Check 3 — Is a coding resistor already fitted?
Some systems already have the cooling coding resistor fitted but cooling was never enabled — and some do not have it at all. Checking this is a job for a competent installer, because it means inspecting the heat pump wiring at the defined coding-plug position.
If the resistor is already fitted, you may only need an installer to enable cooling in the menu. If it is not, you will need the resistor (Vaillant part 0020266328 / 0020269259) before cooling can be activated.
Check 4 — Ask a Vaillant-approved installer
The most dependable check is to ask a Vaillant-approved installer. They can confirm the cooling option for your exact model and serial number, check whether the resistor is fitted, and tell you whether your emitters — radiators, fan coils or underfloor — are suitable for cooling.
An installer can also flag the bigger question: even a cooling-capable heat pump only cools usefully through emitters designed for it. That is worth knowing before you commit.
Frequently asked questions
Does the model number alone confirm cooling?
Not always. The model designation tells you the product family; cooling can be a model-dependent option within it. Use the installer manual and a Vaillant-approved installer to confirm.
What do VWL and VWF mean?
VWL designates Vaillant air-source heat pumps, including the aroTHERM family. VWF designates certain ground-source units. The cooling resistor sold here is for compatible aroTHERM and VWL units.
How do I know if the resistor is already fitted?
It involves inspecting the coding-plug position in the heat pump wiring, which is a task for a competent installer. Ask a Vaillant-approved installer to check during a service visit.
What if I do not have the installer manual?
You can usually download it from Vaillant’s website using the exact model designation printed on the data plate. A Vaillant-approved installer can also identify the unit for you.
My heat pump can cool — does that mean it will?
Being cooling-capable is only part of it. The heating system must also suit cooling, usually fan coil units rather than radiators. Confirm your emitters with an installer.