Start-up procedures
Starting check
Before starting the unit, even only momentarily, all the machinery supplied by the chilled water, like the air handling units,
pumps, etc. must be checked. The pump auxiliary contacts and the flow switch have to be connected to the control panel
as indicated in the electrical diagram. Before carrying out interventions on the valve regulations, loosen the relevant
valve gland. Open the discharge valve of the compressor. Open the liquid shutoff valve placed on the liquid line.
Measure the suction pressure. If it is lower than 0.42 MPa jumper and strain the solenoid valve on the liquid line. Bring
the suction pressure to 0.45 MPa, then remove the jumper. Charge all the water circuit progressively. Starts up the water
pump of the evaporator with the calibration valve shut and then slowly open it.
Discharge the air from the high points of the water circuit and check the direction of the water flow. Carry out calibration
of the flow by using a measurer (if present or available) or by means of a combination of the readings of the manometers
and the thermometers. In the starting phase calibrate the valve on the pressure difference read on the manometers,
carry out drainage of the tubes and then carry out fine calibration on the temperature difference between the water in and
the water out. The regulation is calibrated in the factory for water in to the evaporator at 12°C and water out at 7°C. With
the general switch open, check that the electrical connections are tightly clamped. Check for any possible refrigerant
leaks. Check that the electrical data on the label correspond to those of the mains supply. Check that the thermal charge
available is appropriate for starting.
Refrigerant seals control
Trane units shipped with the complete charge of refrigerant and are at a sufficient pressure to check the seal after
installing. If the system were not under pressure, blow refrigerants (vapour) into it until pressure is reached and look for
leakage.
After having eliminated the leakage, the system has to be dehydrated with a vacuum pump up to at least 1mm Hg -
absolute pressure (1 Torr o 133.3 Pa). This is the minimum recommended value to dehydrate the plant.
CAUTION! Do not use the compressor to vacuum the system.
Refrigerant charge check
Trane units are supplied with a complete charge of refrigerant. If bubbles can be seen through the peephole with the
compressor running with a full charge and steadily, it means that the refrigerant charge is insufficient.
CAUTION! While refrigerant is being added do not exclude any control system and let the water circulate in the
evaporator to avoid the formation of ice.
Cooling circuit diagram with connection to vacuum pump
To Next Page
Loading...
Need help?
General