Does the Vaillant aroTHERM Plus cool as standard?Cooling-capable hardware, but locked until it is enabled
The Vaillant aroTHERM Plus is a reversible heat pump — Vaillant presents it as a heating, hot-water and cooling platform. But cooling does not work the moment the unit is installed. It is locked until the coding resistor is fitted and an installer enables it. This page explains the difference between capable and active.
Updated
The short answer
No — the aroTHERM Plus does not cool out of the box. The hardware to cool is built in, and Vaillant positions the aroTHERM Plus as a cooling-capable platform, but cooling is supplied locked. It has to be deliberately enabled.
Two things stand between a newly installed aroTHERM Plus and working cooling: the cooling coding resistor must be fitted, and a competent installer must enable cooling in the unit’s settings.
Capable is not the same as active
The aroTHERM Plus is a reversible platform. It can run its refrigerant cycle in reverse to remove heat from your home — the compressor, the reversing valve and the cooling control logic are all already inside the unit.
Vaillant ships these heat pumps configured for heating and hot water only. Cooling is treated as a deliberately enabled option, so it is only ever commissioned on purpose by a competent installer. That is why the unit can be fully cooling-capable and yet not cool a single degree until it is set up.
What it takes to enable cooling
First, the coding resistor — Vaillant part 0020266328, also supplied as the functionally identical 0020269259 — is fitted to the heat pump. Without it, cooling cannot even be switched on in the installer menu.
Second, a Vaillant-approved installer enables the cooling function in the settings and commissions it. Third, the system needs cooling-suitable emitters — fan coil units, or underfloor with dew-point control — because cooling will not work well through ordinary radiators. Check your installer manual and confirm the steps with a Vaillant-approved installer.
Frequently asked questions
Will the aroTHERM Plus cool the day it is installed?
No. The hardware is cooling-capable, but cooling is locked. The coding resistor must be fitted and an installer must enable cooling before it will do anything in cooling mode.
Why is cooling locked if the hardware can do it?
Vaillant ships the aroTHERM Plus configured for heating and hot water only. Cooling is a deliberately enabled option, so it is always commissioned on purpose by a competent installer.
Does fitting the resistor switch cooling on?
No. The resistor authorises cooling — without it, cooling cannot be enabled at all. After it is fitted, an installer still has to enable cooling in the settings.
Which part does the aroTHERM Plus need?
The cooling coding resistor, Vaillant part 0020266328 — also supplied as the functionally identical and interchangeable 0020269259. Confirm compatibility for your exact model with an installer.
Will it cool through my existing radiators?
Not effectively. Cooling needs fan coil units, or underfloor heating with dew-point control. Standard radiators do not provide useful cooling, whatever the heat pump is capable of.