Danfoss Termix VVX-I, Installation Manual, Page: 2 / 24

Installation Guide Termix VVX-I
2.0 Functional description
District heating substation for indirect heating and
instantaneous domestic hot water.
Application
The Termix VVX-I is a complete solution for hot water and
space heating with optimal safety, efficient energy transfer,
service-friendly construction and a compact design. The substation
is used if a heat exchanger is required or on a conversion to district
heating where the existing equipment is unsuitable for direct
connection.
District heating (DH)
The substation is prefabricated with a differential pressure
controller, fitting piece and sensor pockets for insertion of an
energy meter as well as strainers and ball valves.
Heating (HE)
The heating side consists of a plate heat exchanger, safety valve,
manometer, thermometers, ball valves, drain valve, air valve,
expansion vessel and circulation pump. The temperature of the
heating can be controlled thermostatically or by an electronic
controller with an outdoor temperature sensor. Depending on the
application, different heat exchangers dimensioned for central or
floor heating will be used.
Domestic hot water (DHW)
The domestic hot water is prepared in the heat exchanger and the
temperature is regulated with a flow-compensated temperature
controller with integrated differential pressure controller. The
heat exchanger cools the DH water very efficiently, thereby
creating an excellent operating economy. The Danfoss IHPT
valve ensures a stable hot water temperature by varying loads,
supply temperatures and by high and varying differential pressure
without the need for readjusting the valve. This protects the
heat exchanger against overheating and lime scale formation.
Furthermore the IHPT valve has an integrated idle temperature
controller, which keeps the house supply line warm. This shortens
the waiting periods during summer when the heating system is in
reduced operation, which is ideal where high comfort is requested.
2 DEN-GT VI.EH.G3.02 / LUK40440
Danfoss District Energy