Vaillant VR 66 Installation Instructions Manual page 10

INTRODUCTION
3.2.5 Multizone operation mode
The Multizone operation mode is compatible with:
- VRT350
- system, combi and open vent boiler
The information about the heating or hot water demand is sent to
the room thermostat via the control unit to the boiler. The VR66
then decides if the hot water demand needs to be fulfi lled and
drives the valves.
In this way, the boiler can store diff erent target temperatures for
heating and hot water modes.
The multizone mode is only compatible with VRT350.
i
No other room thermostats are compatible.
The multizone mode will NOT support weather
compensation and cannot be used on Y plan systems
with three port motorised valves.
The standard installation for multizone mode is characterised by:
- 1 or 2 port valves for zoning,
- 1 or 2 VRT350 programmable wired room thermostats,
- heating zones and DHW cylinder cannot operate in parallel.
Priorities are defi ned as follows:
Priority levels Function
1 Domestic hot water
2 Central heating
EN
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