Maintenance - Hisense AVWW-28UCSA Installation & Maintenance Manual

9. Maintenance

Regularly inspect units in accordance with the same
items as described in the chapter "Test Run". To
ensure the reliability and service life, the following
additional items should be paid with special attention.
Plate Heat Exchanger Freezing
Regularly inspect the water temperature difference,
pressure difference, detect filter clogging, water
reduction or with air inhalation. If circulating water is
insufficient or water temperature is out of the normal
range, it may give rise to plate heat exchanger freezing.
Stop the unit operating immediately when freezing
occurs in plate heat exchanger. Start the unit again
until the completion of troubleshooting.
Start-up unit repeatedly will deepen freezing degree of
plate heat exchanger. As a result, various damages will
appear inside exchanger and cause refrigerant leakage
and refrigerant pipes containing water.
Deposition and Clogging of Water Pipe
After a period of operation, paticles, dust from outside
and calcium carbonate and other minerals in water will
deposit on the surface of plate heat exchanger.
Electricity consumption will increase as the aggravating
of the deposition. These can lead to insufficient
refrigerating capacity or freezing inside of the plate
heat exchanger.
Regularly clean water filter according to the clogging
degree of water filter. If not, water filter may be broken
because of its abnormal pressure.
It is strongly recommended that cleaning plate heat
exchanger while water filter cleaning is underway. Pay
attention to the following tips and the normal cleaning
methods.
Fig.9.1 Cleaning Loop
Plate heat exchanger cleaning should be conducted by
professionals. Please ask an experienced chemical
industrial company for processing. Please contact your
agent or dealer.
Select right cleaning agents according to the deposition
of dirts on plate heat exchanger. Cleaning agents varys
with the deposition of dirts.
The plate heat exchanger is made of stainless steel, do
not use cleaning agent containing chloric acid or fluoride
to clean it, otherwise, heat exchanger will be damaged,
which results in refrigerant leakage.
After using the cleaning agents, flush water pipes and
heat exchanger with clean water to avoid corrosion of
water system and scales reabsorption after cleaning.
In the case of using cleaning agents, regulate the
concentration,cleaning time and temperature of
cleaning agents according to the deposition of dirt.
After cleaning with acid, neutralization treatment of
waste liquid is required. Contact the waste water
treatment company to treat waste liquid.
Clean agents and nuetralized agents have corrosive
and irritative impacts on eyes, skin and nasal mucosa
etc. Therefore, cleaning work must be conducted with
protective device (such as goggles, protective gloves,
protective shoes, protective masks, protective cloth,
etc.) to avoid inhalation or contact with these agents.
Clogging Types and Cleaning Agent (Reference)
Clogging Types
Scaling
Silt
Rusting
Dust and Sand
Particles
Oil
Plastics
Fiber
Cleaning Agent
Citric Acid, Ethylic Acid or
ortho-phosphoric acid
Detergent/Soap, Household
Detergent and Hot Water