Oil Return From Oil Separator (Chillpac); Oil Return From Evaporator (Chillpac/Pac); By-Pass Function (Chillpac); Flow Evaporator (Chillpac/Pac) - Johnson Controls SABROE Unisab III Control Engineering Manual

• When the new Thermo pump - internal function is used it is only possible to use the
chiller functions Oil return from oil separator and Flow condenser.
Chiller function
- configured
Oil return from oil separator
Oil return from evaporator
By-pass function
(or level control LP/HP)
(or expansion control DX)
Flow evaporator
Flow condenser
Level control LP/HP
Expansion control DX
Table 31

3.6.1 Oil return from oil separator (ChillPAC)

When the compressor starts running the Oil return delay timer is started. When this timer
runs out, the oil return valve is open for the time set in the Oil return open timer. Then the
valve is closed for the time set in the Oil return close timer. Once again the valve is open for
the time set in the Oil return open timer, etc. If the Oil return close timer is set to 0 seconds,
this function will work like the existing Oil return function for a reciprocating compressor.
This function is enabled in Set up/Configuration/Plant/Oil return sep. It is active when the
compressor is running, i.e. when there is feedback from the motor starter.

3.6.2 Oil return from evaporator (ChillPAC/PAC)

The two oil return valves controlled will open when the evaporator level switch gets high and
be kept open until a few seconds after the signal from the switch gets low again. This close
delay time is set in the Oil return evap. timer. The level switch is a float indicator in a vessel
under the evaporator.
This function is enabled in Set up/Configuration/plant/Oil return evap. It is active when the
compressor is running, i.e. when there is feedback from the motor starter.

3.6.3 By-pass function (ChillPAC)

During start-up the by-pass valve must be open for a few seconds. The open time is set in the
By-pass start timer.
This function is enabled in Set up/Configuration/plant/By-pass start. It is active when the
compressor is running, i.e. when there is feedback from the motor starter.

3.6.4 Flow evaporator (ChillPAC/PAC)

A shutdown No evaporator flow is given after a short delay when there is no flow through the
evaporator, i.e. no signal from the evaporator flow switch. The shutdown delay time is set in
the Flow evaporator timer.
This function is enabled in Set up/Configuration/Plant/Flow evap. It is active when the com-
pressor is running, i.e. when the evaporator pump is started.
Compressor control and surveillance
Used I/O Other functions using these I/O
DO19
Thermo pump - internal (recip.)
DI13
Oil return (recip.)
DO18
Oil rectifier (screw)
Oil cooling - normal (screw/recip.)
Thermo pump - external (recip.)
Thermo pump - internal (recip.)
DO16
Dual 4-20 mA HLI valve (screw)
HLI - AKV stop valve (screw)
Motor valve (screw)
DI12 Thermo pump - internal (recip.)
DI11 Cap down blocked
DO016 See By-pass function
AI3
AO2
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