Reverse Rotation Protection And; Commissioning; Scroll Compressor Operation; Dual Pressure Switch - J&E Hall V3 FUSION Technical Manual

•
The unit is equipped with a motor circuit breaker with
thermal overload and magnetic trip short circuit
protection for the unit. It was preset from factory and
never set value higher than set current on wiring
diagram.
Reverse Rotation Protection and Voltage
Unbalance
The condensing unit does not include phase protector
except for model JEHS-1400-B4-L-3 EVI; JEHS-1500-B6-
M-3 and JEHS-1300-B4-M-3 units. Thus, it is necessary to
ensure correct scroll compressor rotation and incoming line
voltage variance within +/-2% during commissioning.
3 phase scroll compressors require proper
phase sequence to secure right rotation and
therefore compression.
•
Do not use a megohmmeter nor apply power to the
compressor while the system under vacuum as this
may cause internal damage to the compressor.
•
Never start the compressor under vacuum (do not
operate the compressor with the low-pressure cut-
out bypassing), as this will cause the rotating part to
overheat very quickly causing premature failure.
•
There must be no more than 10 compressor's start
per hour. A higher number reduces the service life of
the compressor. There is no minimum off time for the
compressors. Adequate minimum run time is
required to ensure proper oil return.

Commissioning

To gain access to the electrical box, turn the motor rated
circuit breaker on the side/front of the unit to the OFF
position and loosen the screws on the left-hand side of the
door. The electrical box is located behind the door. Remove
the screws in the electrical box cover to access components.
Pre startup checks
Before starting the condensing unit, the following checks
should be carried out as a minimum:
•
Check electrical supply is correct and all connections
are sound.
•
All moving parts are free, and guards are fitted.
•
Compressor oil level satisfactory.
•
Initial settings for safety switches and fan speed
control.
•
Overload set correctly on motor rated circuit breaker.
•
All valves are in correct operating position.
•
Initial refrigerant charge.
•
Crankcase heater energized for a minimum of 12 hours
before compressor start-up.
•
Gauge manifold connected to both low and high sides
of system.
Running the unit
•
Run the unit and check compressor and condenser fan
operation.
•
Check system pressures and temperatures, gas charge
and running currents of motors to ensure correct
operation.
Issue: 01.06.2023
•
Check compressor suction superheat. This should be
between 10K and 20K for normal operating
conditions.
•
Final adjustment of safety switch settings and fan
speed control.
•
Allow the system to run for 3 – 4 hours. Check
compressor oil level and top up with the correct oil
type as required. Recheck the compressor oil level
again after 24 hours operation.
•
Carry out final leak test and ensure all panels/covers
are fitted and screws tightened.
•
Log all information along with the system model and
serial numbers for future reference.
•
Ensure that the customer / responsible person is
provided with basic operating instructions and where
electrical isolators are situated in case of emergency.

Scroll Compressor Operation

Scroll compressor motors are designed to run only in one
direction. This is not an issue with single phase compressors
as they will always run in the correct direction. The correct
rotation of a three-phase compressor motor depends on the
connection of the three incoming phases to the unit. Correct
rotation can be determined by a drop in suction pressure
and a rise in discharge pressure when the compressor is
energized. Running the compressor for a short period of
time in reverse direction will have no negative impact but
prolonged running in reverse direction may cause
premature failure. To reverse the rotation of a three-phase
scroll compressor, shut off the incoming power supply to the
unit, swap connection of any two of the three incoming phases
at the unit motor rated circuit breaker, reapply power to the
unit and following compressor restart, recheck operating
pressures.
Compressor rotalock connections
All rotalock connections on compressor models are sealed
with Loctite 554 thread sealant. The connections should be
leak tested at commissioning and during
service/maintenance visits. Refer Table 13 for more
information including recommended tightening torque.

Dual Pressure Switch

The dual pressure switch fitted to condensing units is auto
reset for low pressure side and manual reset for high
pressure (fixed differential) are NOT factory preset for
application.
Figure 6: Saginomiya DNS-D306
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