Dometic PGD1 User Manual

21
EN
VARC Chiller Controls Operation
6.1.4 Maintenance
Maintenance mode is available for troubleshooting. See
“Maintenance Mode” on page 39.
6.2 Powerup and Startup
The VARC Chiller Controller can be operated as a single-
stage or a multi-stage chiller plant. During initial setup,
you configure the system for the number of stages and
the available options. The VARC System is set for supply
water control, but it can be modified for return water
control, if needed.
6.2.1 Normal Stage Startup
The system has a time delay between the staging up of
the various stages:
1. Stage 1 is initiated and starts its operation.
2. When the PID determines that more capacity is
required, stage 2 is initiated.
3. When the system has maintained the chilled water
loop and the PID has determined that no additional
stage is required or has met capacity demand, it
reduces the speed of the compressors.
4. The compressors then operate at minimal speed to
maintain the chilled water loop. If the speed of the
compressor still exceeds the demand, the stage with
the most run hours is turned off.
6.2.2 Operational Checks
When the VARC is enabled, the system performs pre-
startup checks on all chilled water flow switches and HP
switches.
Individual stage faults disable only that stage.
6.2.3 Compressor Startup
The VARC utilizes a BLDC compressor that is capable
of operating at a very high frequency which requires
that the compressor have a ramped startup to establish
proper lubrication so as to not damage the compressor.
This startup has a ramp time and a minimal speed
operation that will last for 100 seconds to allow the
compressor to properly warm up before operating at
maximum speed.
The compressor minimum on time is 60 seconds and
minimum off time is 10 seconds with a minimum time
between starts of 60 seconds. These default parameters
allow the compressor to operate in a safe mode that will
not damage the compressor.
6.3 Operating the Touch Screen
I
Some screens contain pop-up screens with
information. To exit a pop-up, simply touch the X to
close the screen.
6.3.1 Basic VARC Operations
From the Chiller Enable screen, you can perform the
basic VARC operations:
• Change setpoints
• Select Cool, Heat, or Electric Heat
• Monitor water temperature and pump status
• Turn the VARC off
To display the Chiller Enable screen, from the Main
screen, tap Chiller Enable. See “Touch Screen” on
page 5.

Dometic PGD1 Specifications

General

Brand	Dometic
Model	PGD1
Category	Control Unit
Language	English