MCAC-TSM-2008-02 Running and Maintenance
Installation 77
7.2 Routine maintenance
Never perform any cleaning operations before having disconnected the unit from the mains power supply.
Regular maintenance is fundamental to maintain the efficiency of the unit both in terms of operation and
energy consumption. The Technical Assistance Service maintenance plan must be observed, with an
annual service which includes the following operations and checks:
- Filling of the water circuit
- Presence of air bubbles in the water circuit
- Efficiency of safety devices
- Power supply voltage
- Power input
- Tightness of electrical and hydraulic connections
- Condition of the compressor contactor
- Efficiency of the plate heat exchanger heater
- Checking of operating pressure, superheating and sub cooling
- Efficiency of compressor heater
- Cleaning of finned coil (*)
- Cleaning of fan grills
- Cleaning of condensate drain pan.
(*) For“Heat pump” appliances, the checks are to be performed quarterly.
For units installed near the sea, the intervals between maintenance should be halved.
7.3 Extraordinary maintenance
Chemical washing
Chemically wash the plate heat exchanger after every 3 years of operation.
Refrigerant gas content
The chillers are filled with R410a refrigerant gas and tested in the factory. In normal conditions, there should
be no need for the Technical Assistance Service to intervene to check the refrigerant gas. However, over
time, small leaks may develop at the joints leading to loss of refrigerant and draining of the circuit, causing
the unit to function poorly. In this case, the leaks of refrigerant must be identified and repaired and the
refrigerant circuit refilled. Proceed as follows:
- Empty and dry the entire refrigerant circuit using a vacuum pump connected to the low and high
pressure tap until the vacuometer reads about 10Pa. Wait a couple of minutes and check that this value
does not rise to more than 200Pa
- Connect the refrigerant gas cylinder or a filling cylinder to the low pressure line pressure gauge
connection.
- Fill with the quantity of refrigerant gas indicated on the rating plate of the unit.
- Always check the superheating and sub cooling values. In the nominal operating conditions for the
appliance, these should be between 5 and 10°C and between 4 and 8°C respectively.
- After a couple of hours of operation, check that the liquid indicator indicates circuit dry (dry-green)
Important
In the event of partial leaks, the circuit must be completely emptied before being refilled
The R410a refrigerant must only be filled in the liquid state. Operating conditions other than nominal
conditions may produce considerably different values.
Seal testing or identification of leaks must only be carried out using R410a refrigerant gas, checking with a
suitable leak detector.
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