Vaillant Cooling Resistor 0020266328 / 0020269259Activate cooling on aroTHERM Plus, Split & VWL heat pumps
Genuine Vaillant coding resistor — the small connector that authorises a Vaillant aroTHERM or VWL heat pump to run in cooling mode. Sold under part number 0020266328 on earlier batches and 0020269259 on recent production. Functionally identical. UK stock, sold privately for less than half the typical Vaillant-merchant retail price.
Heat pump compatibility
The resistor is used across the Vaillant heat pump range whenever active cooling is enabled. Always confirm against your unit's installer manual before fitting.
| Family | Models | Notes |
|---|---|---|
| aroTHERM Plus | VWL 35/6, VWL 55/6, VWL 75/6, VWL 105/6, VWL 125/6 | Monobloc air-source heat pump. Cooling resistor required for active cooling. |
| aroTHERM Split | VWL ../5 AS S2 series | Split air-source unit. Resistor authorises cooling at the indoor unit. |
| aroTHERM (legacy) | VWL ../5 AS series | Earlier monobloc units. Confirm against installer manual before fitting. |
| flexoTHERM / flexoCOMPACT | VWF series | Ground / brine source units when configured for cooling. |
What the resistor does — and what it doesn't
The resistor does
The resistor does not
Frequently asked questions
What is the Vaillant 0020266328 / 0020269259 cooling resistor?
It is the Vaillant coding resistor (sometimes called a "code plug") that tells a Vaillant aroTHERM or VWL heat pump it is permitted to run in cooling mode. Without the resistor fitted, the heat pump will only operate in heating and hot-water mode. Vaillant supplies it under part number 0020266328 (and the identical part 0020269259 on later production runs).
Which Vaillant heat pumps does it fit?
It fits the aroTHERM Plus VWL ../5 and ../6 series, the aroTHERM Split VWL series, and the flexoTHERM / flexoCOMPACT range when configured for active cooling. Always check the model-specific Vaillant installer manual to confirm the resistor part number for your exact unit before ordering.
Is 0020266328 the same as 0020269259?
Yes. Vaillant has shipped the cooling resistor under both part numbers — 0020266328 on earlier batches and 0020269259 on more recent production. Functionally and electrically they are identical. The part on offer here will work in any installation that calls for either part number.
How do I activate cooling on my aroTHERM after fitting the resistor?
Fitting the resistor is only one half of the job. After it is connected, a Vaillant-approved installer must enter the heat pump's installer menu and enable the cooling function in the settings. The resistor authorises the firmware to allow cooling; the installer-side setting actually switches it on. We strongly recommend involving a Vaillant-approved installer for both steps.
Why is this cheaper than buying direct from a Vaillant merchant?
Vaillant merchants typically retail this part at £100 or more. The price here is genuine surplus stock, sold privately at less than half the typical merchant price. The part itself is the same OEM Vaillant component supplied in factory packaging.
What is the returns policy?
Returns are handled per the eBay listing terms — please read the listing carefully before purchase. The part is sold as a genuine Vaillant component; if the part you receive is not as described, eBay's buyer protection applies in the usual way.
Do you ship outside the UK?
Shipping options are listed on the eBay listing. If you need shipping to a destination not currently shown, please ask through eBay messages before buying.