Automatic Functions; General; Starting Sequence; Cooling Recovery - Swegon GOLD PX Series Operation And Maintenance Instructions

9

AUTOMATIC FUNCTIONS

9.1 General

The GOLD has a number of automatic functions. The operation
of the unit is influenced when certain functions are activated.

9.1.1 Starting Sequence

The GOLD has a starting sequence with factory-preset time delay
between every step as follows:
1. The damper relay is energized and opens the shut-off damper
(if installed).
Time delay: 30 seconds.
2. The extract air fan starts (not applicable if only GOLD SD
supply air handling units are installed) and the heat exchanger
is controlled to provide max. heat recovery (Not applicable to
GOLD SD units without heat exchanger). Additional heating (if
installed) is activated to generate 40% of its max capacity.
Time delay: 90 seconds.
3. The supply air fan starts (not applicable if only GOLD SD
extract air handling units are installed)
Time delay: 180 seconds (from the time when the extract air fan
has started).
4. The temperature regulation function begins according to its
regular settings.
The starting sequence prevents the extract air fan from starting if
the shut-off damper is closed. By starting the extract air fan first,
and the heat exchanger as well, the system also avoids chilling
the premises with cool supply air under cold weather conditions.

9.1.2 Cooling Recovery

Cooling energy recovery is an automatic function that helps the
air handling unit utilize the relative "cooling energy" that may be
present indoors if cooling is required and the outdoor tempera-
ture is high.
The heat exchanger rotates at max. speed and in this way recov-
ers the relative cooling energy or chilliness in the extract air.
The conditions for this function to be activated are that there is a
cooling demand and that the outdoor temperature is 1 °C higher
than the extract air. The function is switched out when the cool-
ing load ceases to exist or when the outdoor temperature is the
same as that of the extract air.
The text COOLING RECOVERY is shown in the hand-held micro
terminal.

9.1.3 Zero Point Calibration

The pressure transducer of the unit is automatically calibrated.
This calibration is carried out 3 minutes after the unit has been
stopped.
The text ZERO PT CALIBR is shown in the hand-held micro termi-
nal.
The fans cannot start while calibration is in progres
9.1.4 anti-frost Monitoring Function – air Heater for
Hot Water
The anti frost monitoring function is always active if the air
heater for hot water connected has been supplied by Swegon.
The function activates a heating device that maintains 13 °C in
the coil while the air handling unit is in operation and 25 °C in
the coil when the unit is stopped. An alarm is initiated and the
unit is stopped if the temperature sensor senses a temperature
below 7 °C.
We reserve the right to alter specifications without notice.
9.1.5 additional cooling – electric air Heater
The fans continue to operate at min speed for 3 minutes after
the air handling unit has been stopped to cool the electric heat-
ing elements if the electric air heater has been operating.
The text ADD COOLING appears in the hand-held micro terminal.

9.1.6 Reduction in output, electric air heater

A min. permissible air velocity of 1.5 m/s is required for prevent-
ing the electric heating elements from becoming overheated
when they are generating full heating output.
If the air handling unit supply airflow drops below the value
that corresponds to an air velocity of 1.5 m/s across the heat
exchanger the heating output of the air heater will be automati-
cally reduced.
The text REDUCTION IN OUTPUT appears in the hand-held micro
terminal.

9.1.7 additional running - Heat exchanger

The rotary heat exchanger automatically continues to rotate ca 1
minute after the air handling unit has been stopped.
It takes a little time for the fans to stop rotating after a stop order
has been entered in the micro terminal. This prevents the admis-
sion of cool supply air into the premises.

9.1.8 Density-corrected airflow

The density of the air is different at different temperatures. This
means that a specific volume of air will change at different air
densities.
The GOLD automatically corrects this, so that correct air volume
is always obtained.
The control equipment always shows the corrected airflow.

9.1.9 Purging Operation

Purging is an automatic function that prevents the rotary
heat exchanger from standing still in the same position
for a longer period when no heating is necessary.
Purging operation is activated when the unit is operating but the
heat exchanger rotor is not rotating. The heat exchanger rotor
then rotates for 10 seconds every 10 minutes to purge its sur-
faces clean of impurities.

9.1.10 Carry-over Control

Whenever the fans generate low airflows, the speed
of the rotary heat exchanger is reduced to an appropri-
ate level for correct purging airflow through the heat
exchanger.
9.1.11 Calculaton of the efficiency of the rotary
heat exchanger
The efficiency is calculated and displayed (0 – 100%).
s.
9.1.12 Pump control for the coil heat exchang-
er
The pump of the pipework package starts when
heat recovery is needed.
If heat recovery is not needed for more than 24
hours, the pump is exercised once a day.
GB.GOLDSK509.091101
www.swegon.com 41