Page 26 - IOM / Rooftop Smart and Linéa™ Range
COMMISSIONING
COMMISSIONING
COMMISSIONING
COMMISSIONING
COMMISSIONING
This work must only be carried out by trained
refrigeration engineers
Before connecting to the power:
- Ensure that the power supply between the building and
the unit meets local authority standards and that the cable
specification satisfies the start-up and operating condi-
tions.
- Ensure that the electrical connections in the control pa-
nel and on the motors are secure.
- Ensure that all drive motors are secure.
- Using the electrical wiring diagram, check the conformity
of the electrical safety devices (circuit breaker settings,
presence and rating of fuses).
At this point attach the manometers to the refrigerant circuit
Powering up the system
- Make sure that the thermostat is located where it will not
be affected by sunlight, drafts or vibration. A position
approximately 1.5 meters from the floor, near the Centre
of the structure is desirable. Connect 24VAC class II
control wiring to thermostt and to unit.
- Connect line voltage power supply from the isolating
switch to the bottom of the compressor contactor in the
unit.
- Unit is equipped with ground screw. Ground unit with a
suitable ground connection either through unit supply
wiring or an earth ground.
- Unit voltage openings must be sealed weather tight after
wiring is completed.
Reverse Cycle Test
On reversible units this test is used to check the switching
of the 4-way valves. Start the reverse cycle with reference
to the cold or hot temperature threshold data according to
the climatic conditions at the time of testing
COOLING START-UP AND ADJUSTMENT
Crankcase Heaters
Three phase units only-Crankcase heaters must be
energized for 24 hours before attempting to start
compressors. Set thermostat levers so there is no demand
to prevent compressor from cycling. Apply power to unit.
Preliminary Check
1. Make sure refrigerant lines do not rub against cabinet
or against each other.
2. Inspect all electrical wiring, both factory and field
installed, for loose connections.
3. Check voltage at the disconnect switch. Voltage must
be within range listed on unit nameplate. If not, consult
power company and have voltage condition corrected
before starting unit.
4. Recheck voltage with unit running. If power is not within
range listed on unit nameplate, stop unit and consult
power company. Check amperage of unit. Refer to unit
nameplate for correct running amps.
5. Make sure filter is in place before start-up.
Cooling Start-Up
1. Set thermostat system switch in “Cool” position, fan
switch in “On” or “Auto” position and adjust room ther-
mostat to a setting below room temperature.
2. Close unit isolating switch.
3. Compressor will start and cycle on thermostat demand
and operation.
Three Phase Compressor Rotation
Three phase scroll compressors must be phased
sequentially to ensure correct compressor rotation and
operation.
At compressor start-up, a rise in discharge and drop in
suction pressures indicates proper compressor phasing. If
discharge and suction pressures do not function normally,
follow these steps:
1. Disconnect power to the compressor and the unit.
2. Reverse any two field power leads to the unit.
3. Reapply power to the compressor and unit.
Discharge and suction pressures should operate at their
normal start-up ranges.
NOTE : The compressor noise level will be significantly
higher when phasing is incorrect and will not provide cooling
when operating backwards.
Charging
It is not recommended that the system be charged below
15° C. If charging below 15° C is required or if system is
completely void of refrigerant, the recommended and most
accurate method of charging is to weigh the refrigerant into
the unit according to the amount shown on the unit rating
plate.
HEATING START-UP
Heating Cycle — Heat Pump
1. Set thermostat switch in “Heat” position and blower
switch in “On” or “Auto” position. Set heating adjustment
lever above room temperature. Close unit isolating
switch.
2. Compressor will cycle on demand from room thermos-
tat and outdoor coil fan will cycle with compressor.
Blower will operate according to position of blower
switch on thermostat.
3. A defrost control is used to prevent excessive outdoor
coil icing. As a defrost cycle is initiated, the reversing
valve switches, inducing heat to outdoor coil. Outdoor
fan stops during this process.
Heating (Optional Electric Heat)
1. When heat requirements exceed heat pump capacity,
the thermostat automatically activates the optional
electric heat.
2. On thermostats equipped with emergency heat function,
emergency heat (auxiliary electric heat) may be
manually activated by placing thermostat system switch
in “Emergency Heat” position.
3. Refer to thermostat operation section for details on
indicator light functions.
