Zehnder Option Box V2 Manuel De L'installateur page 26

If the ComfoFond-L gives a poor result on the
outdoor air temperature at the ventilation unit,
the ventilation unit will turn the ComfoFond-L
off. If the connection with the sensor of the
ComfoFond-L is lost the ventilation unit will
turn the ComfoFond-L off and give the error
GROUND_HEAT_CONNECT_ERROR on the
display of the ventilation unit.
9 Post-heater
Installation
The device supports electrically controlled post-
heaters with 0-10V input. PWM (Pulse Width
Modulation) input is not supported. The device
is only for the control of a post-heater and does
not deliver the needed 230V power supply for the
post-heater.
Only a post-heater with SELV 0-10V
may be used. This means the power
supply of the post-heater must be
double insulated from the sensor and
0-10V control. The device also does
not provide any safety controls such
as a high thermal cutoff.
■ Install a NTC temperature sensor
(10kΩ@25°C) after the post-heater in the
supply air to connector 7a (see the wiring
diagram).
■ Install the 0-10V control of a post-heater to
connector 7b (see the wiring diagram).
■ Make sure the post-heater is equipped with a
high temperature thermal cutoff.
■ Install the power supply of the post-heater
to a different group in the fuse box than the
ventilation unit.
8 Must be determined by the installer of the heating system
26 - EN
The device is equipped with an
optional control for a post-heater to
(pre)heat the supply air.
If the house has very limited thermal
losses (e.g. passive house), the post-
heater may be the only active source
to heat the house. 8 Otherwise, a
post-heater can be used to prevent
for sense of draught.
Commissioning
After installation, commission the post-heater
in the ventilation unit OPTION BOX SETTINGS
menu.
The following menus must be set:
Menu item Function
PROPORTIONAL BAND The proportional band value,
which the ventilation unit must use
(Default = 10ºC) in its calculations for the output
signal.
INTEGRAL TIME The integral time value, which
the ventilation unit must use in its
(Default = 180 s) calculations for the output signal.
The default settings have been optimized for
electrical post-heaters of (CV-MPX 200) 2.4kW
and should be acceptable for electrical post-
heaters between 0.5kW and 3.6kW.
The higher the value of the proportional band,
the less immediate response to an error. The
lower the value, the less stable the response
to measurement errors. If instabilities occur at
stable setpoints (no changes), the proportional
band should be doubled. The higher the value
of the integral time, the slower the response to
errors in time. If instabilities occur to setpoint
changes, the integral time should be doubled.
In the chapter "Proportional Integral Differential
(PID) controller" you can find more information
on the proportional band and integral timer.
Operation
The ventilation unit will control the 7b (control
signal) connector from the information received
with the 7a (temperature sensor) connector and
the setpoint. The first two minutes after powerup
of the ventilation unit the temperature sensor has
not reached the right temperature yet to know if
the post-heater needs to be turned on. Therefore
the post-heater will remain off for at least the first
two minutes after powerup of the ventilation unit.
The end user can influence the behaviour of the
post-heater by means of setting a control mode,
a timer and/or a comfort profile. You can find
information on the possibilities in the user manual
of the ventilation unit.
If the connection with the sensor of the post-
heater is lost, the ventilation unit will turn the
post-heater off and give the error POSTHEAT_
CONNECT_ERROR on the display of the
ventilation unit.