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ZB
Series
Application Guide
3.
Proper indoor and outdoor blower/fan operation should be verified.
With service gauges connected to suction and discharge pressure
4.
fittings, turn on the compressor. If suction pressure falls below
normal levels, the system is either low on charge or there is a flow
blockage in the system.
5.
In single Phase Compressors, if suction pressure does not drop and
discharge pressure does not rise to normal levels the compressor
is faulty. But in Three Phase compressors, reverse any two of the
compressor power leads and reapply power to make sure compressor
was not wired to run in reverse direction.
Before replacing, be certain that the compressor is actually defective.
6.
As a minimum, recheck a compressor returned from the field in the
shop or depot for Hipot, winding resistance, and ability to start.
Experience shows that more than one third of compressors are
determined to have nothing found wrong. They were mis-diagnosed
in the field as being defective. Replacing working compressors
unnecessarily costs everyone.
7.
NEVER test a scroll compressor by closing the suction valve or the
liquid feed to the evaporator and pumping the compressor into a
vacuum.
5.3 Electronic Motor Protection Module and Sensor Functional Check
The following field troubleshooting procedure can be used to evaluate
the solid state control circuit: Refer to Table 4 for a technical data
summary.
Module Voltage Supply Troubleshooting
• Verify that all wire connectors are maintaining a good mechanical
connection. Replace any connectors that are loose.
• Measure the voltage across T1-T2 to ensure proper supply voltage.
• Determine the control voltage by using a voltmeter and then measure
the voltage across the M1-M2 contacts:
a.
If the measured voltage is equal to the control volts then the
M1-M2 contacts are open.
b.
If the measurement is less than 1 volt and the compressor is not
running, then the problem is external to the INT69SU module.
c.
If the voltage is greater than 1 volt but less than the control voltage,
the module is faulty and should be replaced.
Sensor Troubleshooting
• Remove the leads from S1-S2, and then by using an ohmmeter
measure the resistance of the incoming leads.
CAUTION: Use an Ohmmeter with a maximum of 9 VDC for checking – do
not attempt to check continuity through the sensors with any other type of
instrument. Any external voltage or current may cause damage requiring
compressor replacement.
a.
During normal operation, this resistance value should read less
than 4500 ohms ±20%.
b.
If the M1-M2 contacts are open, the measured S1-S2 value is
above 2750 ohms ±20% and the compressor has been tripped
less then 30 minutes then the module is functioning properly.
• If the S1-S2 wire leads read less than 2750 ohms ±20% and the M1-M2
contacts are open, reset the module by removing the power to T1-T2
for a minimum of 5 seconds.
• Replace all wire leads and use a voltmeter to verify the M1-M2 contacts
are closed.
• If the M1-M2 contacts remain open and S1-S2 are less than 2500 ohms,
remove leads from the M1-M2 contacts and jumper together;
CAUTION: Compressor should start at this time. HOWEVER DO NOT LEAVE
JUMPER IN PLACE FOR NORMAL SYSTEM OPERATIONS. THE JUMPER IS USED
FOR DIAGNOSTIC PURPOSES ONLY.
• Go to Compressor Supply Voltage Troubleshooting.
12
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