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SECTION II: INSTALLATION AND MAINTENANCE
II.9.1.4
Inspecting and washing the tube and shell
heat exchangers
DANGER!
The acids used for washing the heat exchangers
are toxic. Use suitable personal protective
equipment.
Plate heat exchangers do not get dirty in nominal operating conditions.
The working temperatures of the unit, the speed of the water in the
channels and the suitable finish of the heat exchanging surface reduce
fouling of the exchangers to a minimum.
Any fouling of the exchangers can be noted by measuring the pressure
drop between the inlet and outlet pipes, using a differential pressure
gauge. Any sludge that may form in the water circuit or any silt that
cannot be trapped by the filter, as well as extremely hard water
conditions or high concentrations of any antifreeze solution used, can
clog the exchanger, thereby affecting the heat exchanging efficiency. In
this case, the heat exchanger must be washed with suitable chemical
detergents. Pre-existing systems must be provided with adequate fill-up
and drain connections.
Use a tank containing weak acid: 5% phosphoric acid or if the
exchanger must be cleaned often: 5% oxalic acid. The liquid detergent
must circulate around the exchanger at a minimum flow rate of 1.5
times higher than the nominal work flow.
The first detergent cycle removes the worst dirt and the final cleaning
cycle is completed with clean detergent. Before starting up the system
again, rinse abundantly with water to get rid of any traces of acid and
bleed any air from the system; if necessary start up the utility pump.
1.
EQU-PF
–EQUH-PF;
2.
Auxiliary cock;
3.
Shut-off gate valve;
4.
Wash pump;
5.
Filter;
6.
Acid tank.
II.9.2
Special Maintenance
These are all those repairs or replacements that allow the machine to keep on working in standard conditions. The spare parts must be identical to the
previous ones. Namely, they must have equivalent performance, dimensions etc. according to the specifications provided by the manufacturer.
Electrical system
Every 6 months
Check power consumption of the unit
Every 6 months
Electric motor of fans
Every 6 months
Besides checking the various electrical components, the electrical
insulation of all the cables and their correct tightening on the terminal
blocks must be verified, paying particular attention to the earth
connections.
The motor must be kept clean with no traces of dust, filth, oil or other
impurities. These could cause it to overheat due to low heat
dissipation.
The bearings are usually watertight with permanent lubrication and
sized in order to last approximately 20,000 hours in standard
operational and environmental conditions.
Checking gas charge and humidity in circuit
(with unit running at full capacity)
Every 6 months
Make sure there are no gas leaks
Every 6 months
Check the operation of the maximum and
minimum pressure switches
Every 6 months
To be performed only by skilled personnel from workshops
authorised, qualified to operate on this type of product.
Bleeding air from the chilled water system
Every 6 months
Drain the water system
Every 12 months
(if necessary)
The unit must be drained if it remains idle during winter.
In alternative, a glycol mixture can be used according to the
information provided in this manual.
Control
Frequency
Notes
Summary of Contents for EQU-PF 2100
Page 60: ...NOTE...
