Control System; System Safeties - Carrier 619FB Service Manual

Deep Vacuum Method
The deep vacuum method requires a vacuum pump capable of
pulling a vacuum of 500 microns and a vacuum gage capable of
accurately measuring this vacuum depth. The deep vacuum method
is the most positive way of assuring a system is free of air and
liquid water (see Fig. 16).
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0 1 2 3
MINUTES
Fig. 16 – Deep Vacuum Graph
Triple Evacuation Method
The triple evacuation process should be used in accordance with
the following figure. Refer to Fig. 17 and proceed as follows:
1 Pump system down to 500 microns and allow pump to
continue operating for an additional 15 minutes.
2 Close service valves and shut off vacuum pump.
3 Connect a nitrogen cylinder and regulator to system and
open until system pressure is 2 psig.
4 Close service valve and allow system to stand for 1 hr.
During this time, dry nitrogen will be able to diffuse
throughout the system absorbing moisture.
5 Repeat this procedure as indicated in Fig. 17. The system is
freed of any contaminants and water vapor.
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
RELEASE CHARGE INTO SYSTEM
Fig. 17 – Triple Evacuation Method
Final Tubing Check
IMPORTANT: Ensure the factory tubing on both the indoor
and outdoor units has not shifted during shipment. Ensure
tubes are not rubbing against each other or any sheet metal.
Pay close attention to feeder tubes, making sure wire ties on the
feeder tubes are secure and tight.
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
4 5 6 7

CONTROL SYSTEM

The 619FB/538FR unit is equipped with a microprocessor control
to perform two functions:
1 Provide safety for the system
2 Control the system and provide optimum levels of comfort
and efficiency.
The main microprocessor is located on the control board of
outdoor unit. Outdoor and indoor units have thermistors used to
monitor the system operation to maintain the unit within acceptable
parameters and control the operating mode.

SYSTEM SAFETIES

3 Minute Time Delay
To protect the compressor, there is a 3 minute delay on break even
if the control is calling for heating or cooling. The compressor has
an additional 1 minute delay when powering the unit on for the
first time, or after a power failure.
Compressor Top Temperature Protection
The unit stops working when the compressor top temperature
protector cuts off, and restarts after the compressor top temperature
protector restarts.
Compressor Discharge Temperature Protection
When the compressor discharge temperature reaches a higher one
than in normal operation, the running frequency is limited based on
the following algorithm:
- - When discharge B  208_F, prohibit increasing frequency
- - When discharge B  217_F, prohibit decreasing frequency
- - When discharge B  230_F, compressor stop operation
- - When discharge B≤194_F, protection is released.
— If the compressor discharge temperature is lower than
194_F (90_C), there is no limit in the frequency.
— If this value is between 194_F and 221_F
(90<T5<105_C), the compressor continues running at
the current frequency.
— If this value is now between 221_F and 239_F
(105<T5<115_C), the frequency will decrease to a lower
level every 3 minutes.
— When the compressor discharge temperature reaches a
value higher than 239_F (115_C), and has been running
at this condition for 5 seconds, the compressor stops.
Fan Speed Protection
When indoor fan speed is below 300RPM for a specific amount of
time the unit stops and the LED displays the failure.
Inverter Module Protection
The Inverter module is protected for abnormalities in current,
voltage and temperature. If abnormal values of any of these take
place, the corresponding code appears in the indoor unit and the
unit stops.
Indoor Fan Delayed Operation
When the unit starts up, the louver will be active immediately and the
indoor fan will operate 10s later. If the operating mode is heating, the
indoor fan will also be controlled by the anti- -cold blow function.
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