11 Maintenance notes
Cleaning agents for heat exchanger
SMGB0099 rev.0 - 12/2016
366
11.6 Cleaning agents for heat exchanger
The aluminium n surfaces of the heat exchanger for all the indoor units of packaged air conditioners are coated with 
a hydrophilic coating to prevent the increase of airstream resistance due the occurrence of condensing water during
cooling operation.
However, if the Aluminium n’s hydrophilic is decreased by the adhesion of contaminants, etc., the following 
phenomenon will happen.
Dew will adhere between each aluminium n space (Bridging Phenomenon)
Increase of airstream resistance
Decrease of the airow volume
Decrease of cooling capacity
In some cases, dew may be splashed from the indoor unit
In order to avoid the malfunction of the unit, we recommend the use of cleaning agent for the aluminium ns.
11.6.1 Recommended specications of cleaning agents for aluminium ns
Effect on hydrophilic coating No effect
Effectiveness against specic 
types of dirt
Grease and Oil Specially effective
Tar Effective
White powder (*1) Ineffective
Possibility of occurrence of cracking (*2) Low
pH of the solution Alkaline or Weak alkaline
Requirement of dilution Yes or No
Personal Protection Equipment (PPE) to be used in handling (*3) Mask, Glasses, Gloves
(*1):  The hydroxide caused by the reaction of aluminium ns and the water condensed on the surface of the ns.
(*2): The possibility of occurrence of cracking was also examined taking into account the results of the examination of the
possibility of occurrence of cracking in Acrylonitrile Butadiene Styrene (ABS) and Polystyrene (PS).
(*3): Personal Protection Equipment (PPE) must be used whenever manipulating chemical products, in order to ensure
safety.
11.6.2 Particularities and benets
HITACHI has ben tested the effect of cleaning benets using special n cleaners for hydrophilic coated ns on the indoor 
units. Those tests were focused on the wettability, and conrmed as follows:
• Cleaning aluminium ns makes its hydrophilicity possible to recover.
• The hydrophilic coating is not damaged even if it’s washed repeatedly by using special cleaning special agents for 
hydrophilic aluminium coatings.
11.6.3 To consider
Before washing aluminium ns, protect the fan motor, the electrical box, the connectors and, in general, all the wiring 
of being splashed with the cleaning products and water. In addition, before starting an air-conditioning operation, after
washing the alumimnium ns, be sure that there is no splashing water on those items.
If the cleaning agents are used incorrectly, it will cause damage to aluminium ns. When using those products, pay 
special attention to the indications referred on each instructions manual
To Next Page
Loading...
Need help?
General
