Discharge Temperature Protection; Shut Down Device; Discharge Check Valve; Shell Temperature - Emerson Copeland YA K1 Series Manual

to quickly rise above a critical temperature. Once this
critical temperature is reached, the ASTP feature will
cause the scrolls to separate and stop pumping but
allow the motor to continue to run. After the compressor
runs for some time without pumping gas, the motor
overload protector will open. Depending on the heat
buildup in the compressor, it may take up to two hours
for the ASTP to reset. The addition of the Advanced
Scroll Temperature Protection makes it possible to
eliminate the discharge line thermostat previously
required in heat pump applications. A graphic
explanation and a short video clip are available on our
website at www.
Compressors in this size range that have ASTP are
identified with the ASTP label shown below in Figure 1.
Scan this code to see
a short video clip
about ASTP.
Figure 1 - ASTP Label

Discharge Temperature Protection

A discharge line thermistor should be used with the
compressors for discharge temperature protection. The
discharge line thermistor should be installed within 6"
(15cm) of the compressor and well insulated. The
maximum discharge line temperature should be no
greater than 275 ֯ F (135֯ C ) within the operating envelope
© 2020 Emerson Climate Technologies, Inc.
emersonclimate.com/ASTP.
unless otherwise noted in the operating envelope. For
enhanced protection,
temperature limit may be used.

Shut Down Device

See Table 1 for shut down device technologies for
specific models. Since Copeland scroll compressors are
also excellent gas expanders, they may run backwards
for a brief period after shutdown as the internal
pressures equalize.

Discharge Check Valve

The YA and YP67-122 compressors include a low mass,
disk type check valve in the discharge fitting of the
compressor. The YA and YP137-182 compressors
include a spring assist, disk-type check valve in the
discharge fitting of the compressor. The check valve
prevents the high pressure gas in the condenser from
rapidly flowing back through the compressor after
shutdown. The check
Performance of the check valves for recycling pump
down applications hasn't been evaluated at all pressure
differentials. Low pressure differentials may result in
unacceptable leak-back rates.

Shell Temperature

WARNING
Compressor top cap temperatures can be very hot.
Care must be taken to ensure that wiring or other
materials which could be damaged by these
temperatures do not come into contact with these
potentially hot areas.

Compressor Cycling

There is no set answer to how often scroll compressors
can be started and stopped in an hour, since it is highly
dependent on system configuration. There is no
minimum off time because Copeland scroll compressors
start unloaded, even if the system has unbalanced
pressures. The most critical consideration is the
minimum run time required to return oil to the
compressor after startup. To establish the minimum run
time, obtain a sample compressor equipped with a sight
tube (available from Emerson) and install it in a system
with the longest connecting lines and highest internal
volume that the system may have. The minimum on time
becomes the time required for oil lost during compressor
startup to return to the compressor sump and restore a
minimal oil level that will assure oil pick up through the
crankshaft. The minimum oil level required in the Yx67-
122 compressors is 1.6" (40 mm) below the center of
the compressor sight-glass. The minimum oil level
required in the Yx137-182 compressors is 2" (50 mm)
6
AE4-1486 R1
a lower discharge
valve is not leak-proof.
line