Publicité
Chilled water pump
The chilled water pump relay closes if the system is in heat or cool mode. The pump
is enabled five seconds prior to the first stage being enabled. The pump is on for
continuous operation when the system is enabled.
Sea water pump
The sea water pump has selectable operating modes between continuous operation or
cycle-with-compressor operation. The default configuration is to cycle with the demand.
The sea water pump relay closes five seconds before the compressor starts in heat
or cool modes. It opens five seconds aer the last compressor cycle is completed. If
immersion heating is available and used, the sea water pump is disabled.
In a multistage configuration the pump outputs can be daisy-chained at the back of the
unit to supply power to the pumps. This allows any stage to supply power to the pumps
when being staged on and off and as a redundant control for the pumps.
9.2.2
Cooling
The system automatically starts cooling depending on temperature setpoint. The pumps
operate as described in
Pump operation
The board energizes the compressor relay if return water/supply water temperature
is above the cooling setpoint and the staging delay has elapsed. The compressor
continues to run until the cooling setpoint is reached or an alarm condition exists.
A stage has a minimum run time of 100 seconds before it can be turned off and a
minimum off time of 120 seconds before it is re-enabled. This minimum on time is
required to ensure that the system is not cycling on and off and not allowing the
compressor to properly warm-up. This ensures proper oil lubrication of the system. If the
system calls for a stage to be toggled on/off, the next available stage is used that meets
the staging criteria.
Load shedding occurs in multistage operation when approaching chilled water setpoint.
The reversing valve is toggled to relieve head pressure at the end of a compressor run
cycle.
Select Cool on the touchscreen or with the display buttons.
9.2.3
Heating
The system automatically starts heating depending on the temperature setpoint. The
pumps operates as described in
Pump operation
Reverse cycle heating
The reversing valve relay is energized to change the unit to operate in Reverse Cycle
Heating mode. The PLC energizes the compressor relay if return/supply water
temperature is below the programmed heating setpoint and the staging delay has
elapsed. The compressor continues to run and the reversing valve remains energized
until the heating setpoint reaches or an alarm condition exists.
Select Heat on the touchscreen or with the display buttons.
Electric heating
The PLC energizes the heater relay if return/supply water temperature is below the
programmed setpoint and the staging delay is elapsed in a multistage configuration.
Select Electric Heat on the touchscreen or with the display buttons.
9.3
Enabling electric heat
1. Press the Prg (program) button.
2. Scroll down to Technician.
3. Press the
(enter) button.
on page 12.
on page 12.
4. Scroll down to Service settings.
5. Press the enter button.
6. Enter the service password
.
3156
7. Scroll down to System Setup.
8. Press the enter button.
9. Scroll down to Electric Heat.
10. Press the enter button.
11. Use the scroll up or scroll down buttons to toggle the setting.
12. Press the enter button to save.
9.4
Adjusting setpoints
1. Press the Prg (program) button.
2. Scroll down to Setpoints.
3. Enter the user password
.
1234
4. Scroll up or scroll down, to select between the setpoints: Heating, Cooling.
5. Press the
(enter) button once.
The heating setpoint value is changed.
6. Press the enter button.
EN
13
Publicité
