Temporary Modes (Override) - Dantherm HCH 5 MKII Manual

Temporary modes (override)

Introduction
Bypass mode
(Free cooling)
Automatic bypass
!
NOTE
Manual bypass
10
The temporary modes are activated manually, except for the automatic bypass, and will tem-
porarily override the settings for the selected main mode. The temporary modes are automat-
ically stopped by a timer, but they can also be deactivated manually (except for the automatic
bypass).
The purpose of bypass is to cool down the house by leading the cold outside air flow directly
into the house avoiding it is heated up in the heat exchanger.
During normal operation (when manual bypass is not activated) the unit cools down by the
means of automatic bypass control, when the inside as well as the outside tempera-tures
allows it, which is the reason why in most cases manual bypass is not necessary.
In houses with large fronts of glass facing south, which causes a large amount of heat-ing,
it can be necessary to activate manual bypass in the early spring or in the autumn, because
the automatic bypass does not automatically activate refrigeration with outside air since the
outside temperature is below 15 °C.
When using manual bypass the unit supplies cool outside air directly to the house for six
hours. Information regarding set points for manual and automatic bypass is found in the
installation guide.
Bypass mode opens the bypass damper, which directs the airflow around the heat exchanger.
The outdoor air will thus be supplied to the house without heat recovery. Bypass mode can
be activated in two ways:
• Automatic bypass
• Manual bypass
The automatic bypass opens/closes the bypass damper automatically when the conditions
for automatic bypass are met.
You can change the setpoints for min. outdoor temperature (Tmin) (default setting: 15°C) and
max. indoor temperature (Tmax) (default setting: 24°C) via PC Tool or the Dantherm HRC3
remote control.
If the conditions for automatic bypass are present, an open damper is indicated
by a constant light in the corresponding LED
Mandatory conditions for allowing activation of automatic bypass:
!
NOTE
• Outdoor air temperature is at least 2 °C lower than the exhaust air temperature
• AND the outdoor temperature is higher than the setpoint (Tmin)
• AND the exhaust air temperature is higher than the set point (Tmax).
If one of the following conditions is met, the bypass will be deactivated:
• Outdoor air temperature is higher than the exhaust air temperature
• Outdoor air temperature is at least 2°C lower than setpoint (Tmin)
• Exhaust air temperature is at least 1 °C lower than setpoint (Tmax)
Energy wasting:
If the bypass temperature settings are set too low, there is a risk that the unit will
open the bypass while the central heating system in the house is active.
When the automatic bypass is active in the demand-controlled mode the air volume will be
adjusted according to the actual cooling need which is decided by the exhaust temperature.
If bypass/cooling is desired and automatic bypass is not active, the bypass can be activated
manually.
The bypass will open if the conditions for manual bypass are met within the defined time
period (default setting is six hours). The time period can be changed via PC Tool.
USER MANUAL
Operation: Temporary modes (override)