Leak testing
The unit should be leak tested monthly. Any leaks found must be repaired immediately.
Evaporator and condenser
The major portion of maintenance on the condenser and evaporator deals with maintaining the
water side of the condenser and evaporator in a clean condition.
The use of untreated water in cooling towers, closed water systems, and so on, frequently results in
one or more of the following:
• The formation of scale
• Incidence of corrosion or rusting
• The formation of slime and algae
It is therefore to the benefit of the user to provide for proper water treatment to provide for
a longer and more economical life of the equipment. Use the following recommendation to
determine the condition of the water side of the condenser and evaporator tubes.
1. The condenser tubes should be cleaned annually or earlier if conditions warrant. If the
temperature difference between the water of the condenser and the condenser liquid
temperature is more than 5°F to 6°F (3°C to 4°C) greater than the difference recorded on a
new unit, it is a good indication that the condenser tubes require cleaning. See Maintenance
for condenser tube cleaning instructions.
2. The evaporator tubes under normal circumstances do not require cleaning. If the
temperature difference between the refrigerant and the chilled water increases slowly over
the operating season, it is an indication that the evaporator tubes may be fouling or that
there may be a water bypass in the waterbox requiring gasket replacement or refrigerant
may have leaked from the chiller.
3. Heat recovery condenser tubes should be evaluated similar to evaporator tubes when the
heating circuit is a treated, closed loop. Fouling could be detected as ability to meet heat load
requirements decreases.
Oil return system
1. Change the dehydrator in the oil return system semi-annually or earlier if the oil return
system fails to operate.
2. When the dehydrator is changed, the nozzle of the eductor should be checked for any foreign
particles that may be obstructing the jet.
Electrical controls
1. All electrical controls should be inspected for obvious malfunctions.
2. It is important that the factory settings of controls (operation and safety) not be changed.
If the settings are changed without Johnson Controls approval, the warranty will be
jeopardized.
Maintenance inspections
To avoid serious operating difficulty, follow a regular inspection procedure. Use the following list of
inspections and procedures as a guide.
Model YK (Style H), R-134a and R-513A52
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