Description of functions and unitsInstallation instructions geoTHERM 0020051574_04 1333.4 Optional accessoriesYou can use the following Vaillant units to enhance the heatpump system. Further information about installing Vaillantunits is available in ¬ Ch. 7.7.VR 60 mixer moduleWith the mixer module, you can expand the control systemof the heating installation by two mixed circuits. You canconnect a maximum of six mixer modules.VR 90 Remote control unitYou can connect a separate remote control unit for the firstsix heating circuits (CH 4 – CH 15).VR 10 standard sensorDepending on the system configuration, additional sensorsmay be required, for example, as supply, return, collector ortank sensors.vrDIALOG 810/2vrDIALOG is a communications unit with software and aconnecting cable that provide the option to diagnose, moni-tor and set parameters for the heat pump on-site from acomputer.vrnetDIALOG 840/2, 860/2The vrnetDIALOG communications unit provides the optionto carry out remote diagnosis, monitoring and to set param-eters from one computer via a telephone connection or anintegrated GSM modem, irrespective of your current loca-tion.VPS heating water buffer tankThe VPS buffer tank is used as an intermediate cylinder forheating water and can be installed between the heat pumpand the heating circuit. It provides the energy that isrequired to bridge any idle periods from the power com-pany.VIH and VDH domestic hot water cylinderThe Vaillant VIH coiled tube tank and the Vaillant VDH dou-ble wall tank are specially designed to be combined withheat pumps and are used for heating and storing hot water.VPS /2 buffer tankThe VPS /2 buffer tank (available as an option with VPM-Wfresh water unit or VPM-S solar charging unit) is used astemporary storage for heating water and can be fittedbetween the heat pump and the heating circuit. It providesthe thermal energy that is required to bridge any idle peri-ods from the power company.Other accessories that are available from Vaillant– Brine concentrate– Filling pump for brine circuit– Heat pumps for brine filling unitOther accessories– Safety group and drain pipe for heating circuit– Expansion vessel for heating circuit– Expansion vessel for hot water circuit– Expansion vessel for brine circuit