(1) The air conditioner maintenance manufacturer tells the contents of the annual maintenance work (each time)

Chilled water pump and cooling water pump inspection, refueling motor, electrical insulation testing, refueling, inspection and replacement of sealing components

The cooling tower is generally maintained for maintenance.

Inspection, replacement and repair of valves, filters, one-way valves, pressure gauges, thermometers, and heat preservation in key parts of the water system.

(2) Shanghai Central Air-conditioning Project tells you what the maintenance work is:

Before maintenance, both the user and the maintenance party will truthfully evaluate the original equipment and system according to the equipment model, operating status (record), operating time limit, and on-site status. If the system needs to be overhauled, the cost will be charged separately through negotiation between the two parties. 

Overhaul costs beyond the scope of maintenance shall be calculated and collected separately through negotiation between the two parties.

All the fillings of the water tower are taken out, descaling at one time, and the cost shall be calculated and collected separately through negotiation between the two parties.