EWWQ090G ÷ EWWQ720L - R410A - Water-cooled scroll chillers
EWLQ090G ÷ EWLQ720L - R410A - Condenser less
EWHQ100G ÷ EWHQ400G - R410A - Heat pump scroll chillers
EWAQ-G 075
- R410A - Air-cooled scroll chillers
EWAQ-
- R410A - Air-cooled scroll chillers
EWYQ-
- R410A - Air-cooled scroll heat pumps
Air and Water cooled scroll chillers & heat pump
Operation
Manual
Operation Manual
52
EWWQ - EWLQ - EWHQ
EWAQ - EWYQ
Air or Water cooled scroll chiller &
heat pump
D-EOMHW00107-15EN
condition or high ambient temperature or problems with the condenser fans.
Check with the local maintenance if corrective actions are required. Circuit will be
protected by preventive logic.
High Amb Limit
Ambient temperature is higher than 46.6°C the unit capacity will be limited to
50% in case of single circuit units.
Defrost
This circuit is performing a defrost procedure
If the circuit is allowed to start, the starting sequence is initiated. Starting sequence is described in
a simplified version with the following flowchart.
5.3 Circuit Capacity Control
Once a Circuit is started, capacity will be adjusted according to thermostat control requirements.
However, there are some limitations which override the capacity control in order to prevent the
chiller from abnormal running conditions. These preventions are summarized below:
Low Evaporating Pressure
High Condensing Pressure
5.3.1 Low Evaporating Pressure
When the circuit is running and the evaporating pressure drops below the safety limits (see section
4.9.2) the circuit control logic reacts at two different levels in order to recover the normal running
conditions.
If the evaporating pressure drops below the Low Pressure Hold limit, a new starting of the
compressor is inhibited. This condition is indicated on the controller display in the circuit status as
“
Run: Evap Press Low”. The status is automatically cleared when the evaporating pressure rise
above the Low Pressure Hold limit by 20 kPa.
Is the circuit required to start?
Valve preopening
First Compressor start
N
N
Thermostat control
Shutdown signal for thermostat or alarm?
Pumpdown of circuit then switch compressor off
