Dantherm HCV 3, Installation And Service Manual

Page: 67 / 166

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ersi
on
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.2
011
Fault finding instruction,
continued
Inconvenience,
con-
tinued
Inconvenience Cause Action
The unit is a HCV 3, which
does not have a built-in by-
pass-module. There are no malfunctions.
The outside air might be
heated up before entering the
house. If necessary, move the inlet
grille to the north side of the
building.
The temperatures are exceed-
ing the established limits, which
must be met in order to achieve
cooling by means of bypass.
See the section “Set points and
control strategies” on page 15. Push the manual bypass but-
ton and cooling will be active
for the next 6 hours.
The unit is not
cooling suffi-
ciently.
The bypass-damper is stuck or
the damper motor is defective. Check the bypass module and
replace the damper motor if
necessary.
Unstable opera-
tion, with a wide
variation of air
flow rates. The unit is probably set to
Automatic Demand Mode
which is varying the air flow
rate according to the needs in
the need of the house and the
indoor humidity level.
There is no malfunction on the
unit. It is recommended to set the
unit in Manual Operation Mode
and choose the fan step which
meets the demands most op-
timal (normally Fan Step 3).
It is not advisable to operate at
air flow rates beneath the de-
fined flow rate demanded in
the house, which have a refer-
ence to national law regula-
tions; otherwise there might be
a risk of damage from damp
and reduced air quality.
The unit might be operating
with too high level of air ex-
change compared to the size
and needs of the house. Check if the air flow rates corre-
spond the size of the house and
ventilation load, do this by con-
trolling the air flow rates, which
is described “How to balance
the unit” on page 49. The house is be-
ing unnecessarily
dried out.
The unit has been set to oper-
ate at the nominal air change
(Fan Step 3) in Manual Operat-
ing Mode. Low level of humid-
ity can be observed especially
during winter when the outside
air is very dry. Switch to Automatic Demand
Mode or set the air flow rate at
Fan Step 2 or 1 in Manual Op-
eration Mode.
Using Fan Step 2 or 1 is
only recommended for a short
period of time.
Continued overleaf