6PA W
In either of the modes the circulation pump will not activate if the heat-
transfer medium pressure relay DD1 contacts are open. The pressure relay protects the
circulation pump against «dry» running. If the water coil circuit is not equipped with
pressure relay DD1 install a jumper wire on contacts 11-12 (see Fig. 11) and 14-15 (see
Fig. 11) to enable the circulation pump operation. Circulation pump protection may not
be guaranteed without a pressure relay.
Compressor and Condenser Unit Operation
To enable the CCU operation install the unit control panel (see Fig. 10) on the serviced premises.
To activate the cooling mode change the setting on the control panel using button 2 (see Fig. 10)
as conrmed by * symbol on the control panel screen. The ACS switches to cooling automatically on
ambient temperature exceeding +20 0C .
In this mode the water valve is completely closed. The air cooler compressor and condenser unit
(CCU) is activated on room temperature exceeding the pre-set value.
The CCU deactivates on room temperature reverting to the pre-set value. To prevent CCU
overloading due to frequent activation/deactivation there is 600 s interval between the CCU shutdown
and subsequent activation (Min. Act. Time parameter set from the controller menu, see Table 2).
In the «Heating» mode the ACS additionally performs the following functions:
when the fan is on the ACS maintains the supply air temperature at the pre-set level (set from
the control panel) by actuating the water coil valve;
on fan activation command the ACS warms-up the water coils for n minutes (Warm-up Time
parameter set from the controller menu (see Table 2), factory setting 180 s)prior to the fan
start by means of complete opening the water coil valve.
when the fan is o the ACS maintains the return water temperature downstream of the water
coils at the pre-set minimum level of +20°С.
In both «Heating» and «Cooling» modes ACS protects the water coils against freezing (using the
input data from the air duct thermostat sownstream of the water coils).
If freezing is imminent the control system automatically shuts down the fans, closes the ambient
supply air damper, opens the water coil valve completely and activates the circulation pump.
Circulation Pump Operation.
In the ACS «Heating» or «Cooling» mode the circulation pump activates automatically while the
fans are on or on water coil warm-up initialization and deactivates on fan switching o.
While on standby the circulation pump activates on freezing danger detection irrespective of the
ACS mode.
When freezing is no longer imminent and upon emergency reset the circulation pump reverts to
the pre-emergency state - i.e. continues operation or goes on standby.
