Ventilation unit with heat recuperation
DUOVENT
®
COMPACT RV
15
For correct connection, the direction of water flow is indicated on the housing of the unit by auxiliary labels.
heating
water
inlet
heating
water
outlet
air flow
direction
air flow
direction
heating
water
outlet
heating
water
inlet
counter-current exchanger connection
For the water heater to function properly, it is necessary to bleed the heater after connecting and filling the system with heating water. The vent
screws are located directly at the heat exchanger connection necks. The vent screws are accessible from the outer operating side of the unit.
Before starting service work on the heat exchanger (when replacing it), it is necessary to drain the heating water distribution system connected to
the heat exchanger and drain the heat exchanger itself using the drain screws on the heat exchanger collectors. The heat exchanger can then be
disconnected from the heating water distribution system and removed from the unit.
Max. operating water temperature of water heaters:
+110 °C
Max. operating water pressure of water heaters:
1.6 MPa
Hydrogen exponent of heating water: pH 7-9
Heating water hardness: 1.0 mval / l
If necessary, water heaters can be operated with a heating medium based on a solution of water and ethylene glycol or propylene glycol -
antifreeze mixture.
All pipes must be connected independently of the heat exchangers - the heating water pipes must not act on the necks of the heat exchangers
due to their weight and expansion. We recommend the antifreeze mixture as a heat transfer medium for all outdoor units.
Units taken out of service must be protected against freezing by draining water from all parts of the unit. Residual water from the exchanger can
be expelled with compressed air.
When starting the unit at an outdoor air temperature below +5 °C, the active fluid supply to the heater must be opened before starting the fan,
which must have the projected temperature at the heating water supply to the heater. I.e. the boiler circuit must be in operation, the boiler must
heat and provide the warm water to the system.
The water heater heating system of outdoor variant units is recommended to fill with the anti-freeze mixture.
!
CAUTION!
For unit variants with water bivalence and heat pump (marked DXr DCA or DXr DCB in the unit
code), it is recommended to use an antifreeze mixture of water and ethylene glycol (eg. FRITERM
E Stabil) in min. concentration 1:2 (i.e. 1 part of FRITERM E Stabil: 2 pats of water). If the
antifreeze mixture cannot be used, a year-round supply of heating water must be provided in front
of the water heater control valve so that all frost protection functions are active. For units that are
not equipped with a Digireg
®
or control system, it is recommended to install a capillary antifreeze
thermostat behind the water heater in the direction of air flow, which activates the antifreeze
protection functions of the water heater in the customer control system of the unit.
