Dantherm HRV 5, Service Manual

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Functions
Introduction This section gives you a description of the various functions of HRV 5.
Summer operation In the summer when the room air temperature is higher than the outside air and cooling
is required, it is not necessary to heat the outside air before it is blown into the house.
In summer mode the heat exchange between supply air and extract air is deactivated
by stopping the heat exchanger. Fresh outside air is then led into the house at un-
changed temperature.
The summer mode function automatically switches off the heat exchanger when the fol-
lowing three conditions are fulfilled at the same time:
No. Condition
1 Outdoor air T1 is colder than the extract air T3
2 The extract air is warmer than the T
max
set point
3 Outdoor air temperature is higher than 14 °C (air used for cooling should not
be colder than that)
The summer mode function automatically switches on the heat exchanger when one of
the following three conditions is fulfilled:
No. Condition
1 Outdoor air is warmer than the extract air+2
2 Extract air is colder than T
max
-2
3 Outdoor air is colder than 12 °C
The hysteresis of 2 degrees ensures that the heat exchanger does not start and stop
too frequently in the transition period.
See the
section ”User’s guide”, page 21 for adjustment of summer mode settings and
how to change these settings.
Summer mode
screen
When the heat exchanger is stopped this will be indi-
cated by a by-pass symbol above the plant icon inside
the house icon. This symbolises that the air is by-
passing the heat exchanger.
Continued overleaf