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Maintenance Procedures
Note: Bubbles in the sight glass do not necessarily
indicate loss or lack of refrigerant charge. Bubbles
(commonly know as 'flashing') will occur until the
expansion valve settles out the refrigerant flow. If
the refrigeration pressures are in the normal range,
the unit is most likely adequately charged.
'Flashing' could also indicate excessive superheat
adjustment of the thermal expansion valve.
Quarterly
The quarterly maintenance inspection is a comprehensive
event that examines all aspects of the chiller/heater to
identify early problems before they can damage a chiller/
heater and require major repair or refurbishment:
1. Inspect refrigerant pressures and temperature set
points.
2. Inspect chiller/heater superheat and sub-cooling.
System superheat should be 10 °F to 12 °F (55 °C to 6
°C). System sub-cooling should be 10+ °F (5.5+ °C).
3. Inspect the approach evaporative - entering
evaporator water/glycol mixture temperature and
leaving evaporator water/glycol mixture temperature
as well as the condenser approach.
4. Inspect strainers.
5. Collect chilled water/glycol mixture sample for
professional analysis. Check for cleanliness. Drain and
refill with clean solution if excessive sludge or dirt is
present. Flush the chiller/heater prior to refilling.
6. Inspect water/glycol mixture levels. Add glycol as
required.
7. Inspect crankcase heaters for proper operation.
8. Inspect the water piping for signs of leaks at joints and
fittings.
9. Inspect refrigerant piping circuit for signs of oil or
refrigerant leakage. Conduct 'sniffer test' to find
refrigerant leaks.
10. Tighten all refrigeration piping connections (e.g.
rotalock stems and packing nuts, Schrader valves, and
ball valves).
11. Install a manifold and gauge set to observe chiller/
heater's refrigeration operating pressures.
a. Verify that the pressure controls (low pressure and
high pressure switches) are 'cutting in' and 'cutting
out' at the appropriate pressures.
b. Verify refrigerant charge by recording the
superheat and sub-cooling temperatures and
visually inspect the sight glass.
c. Observe head pressure for signs of improper
condensing from low flow, clogged strainers, or a
modulating expansion valve issue.
12. Check compressor motor amperage draws and voltage
supplies and maintain a record of those values. Verify
that they are within the name plate rating. Also, check
58
for voltage imbalance. The chiller/heater's phase
monitor will open if the voltage imbalance exceeds 4%.
13. Check for excessive wear or burned contacts on motor
starters. Replace contacts if in doubt.
Annually
The annual chiller/heater maintenance inspection is
critical to the long-term performance of the chiller/heater.
Whether a chiller/heater has a service life of 15 years or 30
years is almost entirely dependent upon how consistently
and how diligently the annual maintenance inspection is
performed. The annual event is a comprehensive
inspection that examines all aspect of the chiller/heater to
identify small problems before they can become major
issues that damage a chiller/heater and require significant
repair or refurbishment.
1. Inspect all electrical connections for damage and
ensure terminals are tight. Inspect all contactors for
pitting and corrosion and replace as necessary.
WARNING
Hazardous Voltage!
Failure to disconnect power before servicing could
result in death or serious injury.
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Verify that no power is present
with a voltmeter.
2. Inspect fuses to ensure they are undamaged and
functioning and are of the correct amperage rating.
3. Energize each compressor and check refrigerant
pressures, signs of overheating, and oil leaks. Check
chiller/heater for leaks with a halogen leak detector.
Inspect packing nuts on rotalock valves (if so
equipped), threaded connections of rotalock valves,
flared fittings on refrigeration gauge and pressure
switches, and access ports on Schrader valves.
WARNING
Refrigerant under High Pressure!
Failure to follow instructions below could result in an
explosion which could result in death or serious injury
or equipment damage.
System contains refrigerant under high pressure.
Recover refrigerant to relieve pressure before opening
the system. See unit nameplate for refrigerant type. Do
not use non-approved refrigerants, refrigerant
substitutes, or refrigerant additives.
4. De-energize each compressor and inspect terminals
for pitting, corrosion, and loose connections.
5. Inspect that the oil level is visible in each compressor
and not discolored or bubbled. Annual oil samples
ARTC-SVX005A-EN
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