Air and Water cooled inverter chillers and heat pump
D-EOMZC00105-17EN
Operation Manual
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EWAD TZ - EWAD TZ B -EWWD VZ
Air and Water cooled inverter chillers and
heat pump
Overall Status
Status
Description
Off:
Ready
Circuit is off waiting for a stage up signal from thermostat control
Stage Up Delay
Circuit is off waiting for the stage up delay to expire.
Cycle Timer
Circuit is off waiting for the compressor cycle timer to expire
BAS Disable
Circuit is off by BAS signal. Check with the BAS company how to start the unit.
Keypad Disable
Circuit is off by the local or remote HMI. Check with your local maintenance if it can be
enabled.
Circuit Switch
Circuit is off by Enable switch. Turn the Enable switch to 1 to allow the circuit start up
procedure to start
Oil Heating
Circuit is off because the oil temperature is too low to guarantee a proper lubrication of
compressor. Heating resistor is activated to eliminate this temporary condition. It’s
suggested to power up the unit in advance to avoid this limiting condition.
Alarm
A circuit alarm is active. Check the alarm list to see what is the active alarm inhibiting the
circuit to start and check if the alarm can be cleared. Refer to section 6.before proceeding.
Test Mode
Circuit mode set to Test. This mode is activated to check operability of onboard circuit
actuators and sensors. Check with the local maintenance if the Mode can be reverted to
Enable.
Max Comp Starts
Compressor starts exceed the maximum number of starts per hour.
VFD Heating
Inverter on compressor cannot start because of low internal temperature. Heating resistor
is activated to eliminate this temporary condition. It’s suggested to power up the unit in
advance to avoid this limiting condition.
Maintenance
A component needs to be replaced or maintained. Refer to section 6.before proceeding.
EXV
Preopen
EXV prepositioning before compressor starts.
Run:
Pumpdown
Circuit is shutting down because of thermostat control or pumpdown alarm or because the
enable switch has been turned to off.
Normal
Circuit is running within the expected operational conditions.
Disch SH Low
Discharge superheat is below the acceptable value. This is a temporary condition that
should disappear after few minutes of operation.
Evap Press Low
Circuit is running with low evaporator pressure. This could be due to a transitory condition
or a lack of refrigerant. Check with the local maintenance if corrective actions are required.
Circuit is protected by preventive logic.
Cond Press High
Circuit is running with high condenser pressure. This could be due to a transitory 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 LWT Limit
Circuit is running with a high water temperature. This is a temporary condition that will limit
the maximum compressor capacity. Reduction of the water temperature will allow the
compressor to reach the full capacity.
High VFD Amps
Inverter current is higher than the maximum allowed current. Preventive logic will protect the
inverter.
5.2.5
Circuits start sequence
To allow a circuit start up is required to enable the circuit using the enable switch located on the unit switchbox.
Each circuit is equipped with a dedicated switch identified with Q1, Q2 (if available) or Q3 (if available). The
enable position is indicated with a 1 on the label whereas the 0 position corresponds to disable.
The status of the circuit is indicated in the View/Set Circuit
– Circuit #x – Status/Settings. The possible status
will be described in the following table.
If the circuit is allowed to start, the starting sequence is initiated. Starting sequence is described in a simplified
version with the further flowchart.