Crankcase Heat-Three Phase; Minimum Run Time; Reversing Valves; Low Ambient Cut-Out - Emerson Copeland Scroll ZP K6 Series Bulletin

together for clamping with the vertical shell seam weld
coming up through the area where the crankcase heater
is clamped together. See Figure 5 for details. Tighten
the clamp screw carefully ensuring that the heater is
uniformly tensioned along its entire length and that
the circumference of the heater element is in complete
contact with the compressor shell. It's important that
the clamp screw is torqued to the range of 20-25 in-lb
(2.3-8 N m) to ensure adequate contact and to prevent
heater burnout. Never apply power to heater in free air
or before heater is installed on compressor to prevent
overheating and burnout.
Crankcase Heat - Three Phase
A crankcase heater is required for three-phase
compressors when the system charge exceeds the
compressor charge limit listed in Table 4.

Minimum Run Time

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. Other
than the considerations in the section on Brief Power
Interruptions, 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
that are approved for the system. 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. Cycling the compressor for a shorter period
than this, for instance to maintain very tight temperature
control, will result in progressive loss of oil and damage
to the compressor. See AE17-1262 for more information
on preventing compressor short cycling.

Reversing Valves

NOTICE
Reversing valve sizing must be within the
guidelines of the valve manufacturer. Required
pressure drop to ensure valve shifting must be
measured throughout the operating range of the
unit and compared to the valve manufacturer's
data. Low ambient heating conditions with low
© 2015 Emerson Climate Technologies, Inc.
flow rates and low pressure drop across the valve
can result in a valve not shifting. This can result
in a condition where the compressor appears to
be not pumping (i.e. balanced pressures). It can
also result in elevated compressor sound levels.
ZP*K6 compressors are equipped with the transient
sound solution feature that allows the compressor to run
throughout the defrost cycle transition with low running
sound. It is not necessary to de-energize the ZP*K6
compressor when entering and exiting the defrost cycle.
The reversing valve solenoid should be wired so
that the valve does not reverse when the system is
shut off by the operating thermostat in the heating
or cooling mode. If the valve is allowed to reverse at
system shutoff, suction and discharge pressures are
reversed to the compressor. This results in pressures
equalizing through the compressor which can cause
the compressor to slowly rotate backwards until the
pressures equalize. This condition does not affect
compressor durability but can cause unexpected sound
after the compressor is turned off.

Low Ambient Cut-Out

A low ambient cut-out is not required to limit air-to air
heat pump operation. Air-to-water heat pumps must
be reviewed since this configuration could possibly run
outside of the approved operating envelope (Figure 1)
causing overheating or excessive wear.

Oil Type

Polyol ester (POE) oil is used in ZP*K6E compressors.
See the compressor nameplate for the original oil
charge. A complete recharge should be approximately
four fluid ounces (118 ml) less than the nameplate
value. If additional oil is needed in the field, Copeland
Ultra 32-3MAF, Lubrizol Emkarate RL32-3MAF, Parker
Emkarate RL32-3MAF/(Virginia) LE32-3MAF, or Nu
Calgon 4314-66 (Emkarate RL32-3MAF) should be
used. Copeland Ultra22 CC, Hatcol EAL22CC, and
™
Mobil EAL Arctic 22 CC are acceptable alternatives.
CAUTION! POE must be handled carefully and
the proper protective equipment (gloves, eye
protection, etc.) must be used when handling POE
lubricant. POE must not come into contact with any
surface or material that might be harmed by POE,
including without limitation, certain polymers (e.g.
PVC/CPVC and polycarbonate).
7
AE4-1400 R1
™