However, if
ready mode
and
saving mode
differential temperatures are too small or if the compressor rest time (
rt
) is too
short, the ems controller cycles the compressor on the compressor rest time (
rt
) as the compressor rest time (
rt
) over-
rides the differential temperatures.
If the compressor runs continuously for too long without reaching the set point (
S P
) temperature, a refrigeration system fail-
ure (
rS F
) alarm activates alerting to possible problems with the refrigeration system.
ems controllers can monitor the refrigeration system temperature using a condenser sensor. Monitoring the refrigeration
system temperature can help detect problems, such as a blocked condenser.
If the temperature measured on the condenser sensor reaches the condenser high temperature (
C t
), the ems controller
disables the compressor and activates the (
Ht
) alarm. The condenser high temperature (
C t
) is set by measuring the refri-
geration system temperature when the condenser is 75% blocked.
ems controllers manage the failure of a temperature sensor as follows:
l
Appliance sensor failures indicated by
PF1
alarms, ems controllers stop running the compressor and then waits 60 seconds before reboot-
ing (switch off and then switch on).
If the fault continues, the ems controller repeats and continues the cycle.
l
Condenser sensor failures indicated by
PF2
alarms, ems controllers continue running the compressor. ems controllers alternate the dis-
play between
PF2
and the appliance sensor temperature.
l
PF2 alarms may also indicate a problem with the gas cooler high temperature sensor when the cooler is a CO2 (R744) version.
An ems55
advanced
CO2controller will alternate between PF2 and the gas cooler
temperature sensor temperature.
l
For evaporator failures indicated by
PF3
alarms, ems controllers continue running the compressor.
ems controllers alternate the display between
PF3
and the appliance sensor temperature.
Note:
l
Ht alarms do not apply to CO2 coolers
For more information about the parameters used in
compressor management
:
l
See "refrigeration system failure (Ct)" on page 70
l
See "differential (dIF)" on page 72
l
See "compressor rest time (rt)" on page 79
l
See "set point (SPC or SPF)" on page 80
l
See "saving set point (SSP)" on page 80
For trouble shooting information:
l
See "how to troubleshoot refrigeration system failure (rSF) alarms" on page 50
l
See "how to troubleshoot temperature sensor alarms" on page 50
5.9
evaporator fan management
ems controllers, depending on model, can be configured to manage the evaporator fan.
ems controllers always run the evaporator fan when the compressor is running.
For periods that the compressor is not running, the ems controllers run the evaporator fan according to the evaporator fan
cycle.
Note: The evaporator fan cycle is not applied whilst the compressor is not running during a defrost period.
The evaporator fan cycle is defined by the fan cycle on (
FC O
) and fan cycle off (
FC F
) parameters.
The fan cycle starts with a fan cycle on (
FC O
) period as shown below.
ems55advanced and ems55Radvanced / General Use
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