Crankcase Heater; Pressure Controls; Ipr Valve; Motor Protection - Emerson Copeland Scroll K5 Series Application Bulletin

rapidly for a short period of time. When the crankcase
temperature difference falls below the recommended
50°F (27°C), our recommendation is the duration should
not exceed a maximum (continuous) time period of two
minutes and should not go lower than a 25°F (14°C)
difference.
Contact your Emerson Climate Technologies
representative regarding any exceptions to the above
requirements.

Crankcase Heater

Crankcase heaters are required, on outdoor systems,
when the system charge exceeds 17 lbs.
Table 2 includes crankcase heaters intended for use
only where there is limited access. The heaters are
not equipped for use with electrical conduit. Where
applicable electrical safety codes require heater lead
protection, a crankcase heater terminal box should be
used. Recommended crankcase heater terminal cover
and box numbers are also listed in Table 2 If there
are any questions concerning the application, contact
Application Engineering.

Pressure Controls

Both high and low pressure controls are required. The
minimum and maximum pressure setpoints are shown
in Table 4 at the end of this bulletin.

IPR Valve

There is no internal pressure relief valve in these larger
horsepower scrolls. Therefore a high pressure control
located prior to any shut-off valves is mandatory. There
is an access port located on the compressor discharge
rotalock fi tting to accommodate this control.

Motor Protection

Motor protection in the K5 compressor for refrigeration is
either by internal line break (ILB) or solid state protection
with positive temperature coefficient (PTC) sensors. The
type of motor protection is based on the compressor
motor version. An "F" in the second character indicates
line break while a "W" indicates PTC protection. For
example, a ZF34K5E-TFC has ILB and a ZB95K5E-
TWC uses PTC sensors.

PTC Motor Protection

There are four PTC (Positive Temperature Coeffi cient)
internal thermistors connected in series that react
with avalanching resistance in the event of high
temperatures. The thermistors are used to sense motor
temperatures. The thermistor circuit is connected to the
protector module terminals S1 and S2.
© 2012 Emerson Climate Technologies, Inc.
Printed in the U.S.A.
Application Engineering
B U L L E T
When any thermistor reaches a limiting value, the
module interrupts the control circuit and shuts off the
compressor. After the thermistor has cooled suffi ciently,
it will reset. However, the module has a 30 minute time
delay before reset after a thermistor trip.

Programmable Logic Controller Requirements

If the INT69 (071-0660-00) module is applied in
conjunction with a Programmable Logic Controller, it is
important that a minimum load is carried through the
M1-M2 control circuit contacts.
The minimum required current through the module
relay contacts needs to be greater than 100 milliamps
but not to exceed 5 amps. If this minimum current is
not maintained, this has a detrimental effect upon the
long-term contact resistance of the relay and may result
in false compressor trips.
PLC operated control circuits may not always provide
this minimum current. In these cases modifi cations
to the PLC control circuit are required. Consult your
Application Engineering Department for details.

Kriwan INT69 Module and Sensor Functional Check

Module specifi cations are listed in Table 3 at the end of
this bulletin. Refer to Figure 2 for wiring schematic. The
following fi eld troubleshooting procedure can be used
to evaluate the solid state control circuit:
Motor Protector 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 motor protector module.
c) If the voltage is greater than 1 volt but less than
the control voltage, the motor protector module
is faulty and should be replaced.

Sensor Troubleshooting

• Remove the leads from S1-S2, and then by using an
Ohmmeter to measure the resistance of the incoming
leads.
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