Start Up; Description Of Standard Equipment; Figure 25 Geothermal Compressor Logic Control Board - Bard QW2S3DA Installation Instructions Manual

START UP

Description of Standard Equipment

Low Pressure Switch
NOTE This unit is supplied with two low pressure
switches installed, a 55 PSIG and a 75 PSIG.
The 75 PSIG is wired into the system. This switch is
suitable for water loop (boiler/tower applications).
To avoid nuisance lockouts for ground loop application
with antifreeze, the 75 PSIG switch should be
disconnected and connect the 55 PSIG switch.
The leads for both switches are located in the lower
electrical connection panel. The switch bodies are
marked with pressure settings. The 75 PSIG switch has
blue leads. The 55 PSIG switch has yellow leads.
Water Flow Switch
These models are equipped with a water flow switch.
It is a magnetic (sealed) switch that closes electrical
contacts above 3 gallons per minute. This enables
the compressor to shut down in the event of low water
flow conditions, thus preventing long-term mechanical
issues.
During dehumidification, the water flow switch
requirement of 3 gallons per minute is bypassed for
purposes of water modulation.
Water Modulating Actuator (iSeries Smart Actuator)
These models are equipped with an iSeries
Smart Actuator. The iSeries Smart Actuator is a
microprocessor-based valve designed to provide a
setpoint (fixed) temperature to an HVAC system by
modulating the position of a 3-way mixing valve.
The actuator has two electrical terminals and an
illuminated LED status powered by 24VAC. All
terminals provided with the iSeries Smart Actuator
are removable. The terminals have a label with a
description for each position, indicating their use. The
slot intended for a boiler is not used.
During dehumidification, the iSeries Smart Actuator
is activated. The actuator provides modulation of
the valve, in order to control the water flow to help
accommodate room comfort during dehumidification.
High Pressure Switch
This unit is equipped with a high pressure switch that
will stop the compressor in the event of abnormal high
pressure occurrences.
The high and low pressure switches are included in
a lockout circuit that is re-settable from the room. In
the event of a high or low pressure switch lockout, a
visual indication can be seen from the geothermal logic
control board. See Troubleshooting Geothermal
Logic CCM on page 64 for further explanation.
Manual 2100-738C
Page 32 of 73
Geothermal Compressor Control Module
When the green status light blinks, this indicates that
24 volt power is applied to the board and the controller
is running in normal operation.
On initial power up and call for compressor, a 5-minute
delay plus a random start delay of 0 to 60 seconds is
applied. After the random delay, the compressor relay
is energized (terminal CC). When the Y1 input opens,
the compressor de-energizes.
The geothermal compressor control module is standard
on all models covered by this manual. It is an anti-short
cycle/lockout timer with high pressure, low pressure
and flow switch monitoring and alarm output.
After compressor shutdown, or power disruption,
a 5-minute timer is applied which prevents the
compressor from operating.
Over and Under Voltage Protection
When an under or over voltage condition exists, the
controller locks out the unit. When condition clears,
the controller automatically releases the unit to normal
operation and the compressor restarts after the random
start and anti-short cycle timings are met. The under
and over voltage protection starts at plus or minus
20% from nominal voltage and returns to operation at
plus or minus 10% from nominal voltage. All four LED
fault lights will flash when an over or under voltage
conditions occurs. The over voltage protection can
be disabled by removing the O/V jumper on the logic
control board (see Figure 25).
FIGURE 25
Geothermal Compressor Logic Control Board
O/V Jumper TEST Jumper