TemperZone OPA 465RKTG-P, Installation & Maintenance

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6. OPERATION
6.1 Remote on/off
The remote on/off function can be enabled or disabled
by using a UC6 service tool.
When the function is enabled the remote on/off signal
must connect to input DI7, signal return is DIC1. The
remote on/off signal must be an external voltage free
switched relay contact.
The unit is active when DI7 is connected to DIC1.
6.2 Variable duty units
The UC6 can control a unit where one of the two
compressors is a variable speed compressor or a digital
scroll compressor. Temperzone pre-configures the unit
to the correct compressor type; a UC6 service tool is
required if the compressor type configuration must be
changed.
The capacity input signal must connect to input CS (0-
1V, duty 10% per 0.1V).
For digital scroll compressors the capacity output signal
(compressor modulating valve control signal) is on
output CCS.
The minimum compressor duty is:
20 to 30% for a variable speed compressor
(depends on compressor model)
16% for a digital scroll compressor
When a capacity signal is present on input CS that is
lower than the minimum duty (for example 0.0V) then the
compressor will continue to operate on minimum duty.
Safety functions may place further restrictions on the
minimum duty and may act at any operating condition.
6.3 High pressure protection (HP)
If high pressure transducers are connected to inputs
HP1 and HP2 then a compressor is switched off when
the discharge line pressure reading exceeds 42.0bar.
Instead of high pressure transducers some systems
may be fitted with high pressure switches. These also
connect to inputs HP1 and HP2. When a high pressure
switch activates (electrical circuit opens) the compressor
is stopped.
Similarly, if the condensing temperature reported by an
outdoor coil temperature sensor (connected to TS1 and
TS2) reports a coil temperature above +66°C (cooling
mode) the compressor is switched off.
The UC6 will automatically reduce capacity of a digital
scroll compressor before the maximum value of 42bar /
66°C is reached.
When a compressor is stopped due to high pressure
it is held off for a period of 3 minutes, after which it is
allowed to restart (provided pressure has fallen well
below the maximum).
If three consecutive trips occur then the unit will be
“locked out”. The trip counter is reset to 0 when there
has been no compressor run request for longer than 60
minutes.
Display indication when protection is active -
number 4 (flashing)
6.4 Loss of refrigerant protection (LOR)
When a compressor is running the UC6 continuously
monitors the various temperatures. The controller
software applies logic that enables it to determine
whether the system has an adequate amount of
refrigerant. Signals used for this check are mid-coil
temperatures (TS1, TS2), suction temperatures (ST1,
ST2 and discharge line pressures (HP1 and HP2, if
present).
The check is not made during the first 5 minutes
after a compressor is started to allow pressures and
temperatures to settle.
If the compressor is a variable speed type or a digital
scroll type then the check is made only when the
capacity is at 100%.
When a compressor is stopped due to loss of refrigerant
it is held off for a period of 3 minutes, after which it is
allowed to restart.
If three consecutive trips occur then the unit will be
“locked out”. The trip counter is reset to 0 when there
has been no compressor run request for longer than 60
minutes.
Display indication when protection is active -
number 3 (flashing)
6.5 Indoor coil frost protection (FROST)
When the unit is cooling the evaporating temperature
in the indoor coil must remain above -10°C (adjustable
from -10°C to -2°C by using a UC6 service tool). If this
temperature falls below the threshold then some amount
of ice (frost) is likely to have formed on the indoor coil.
When indoor coil frost protection is activated the
compressor is stopped for 15 minutes, after which it is
allowed to restart.
If three consecutive trips occur then the unit will be
“locked out”. The trip counter is reset to 0 when there
has been no compressor run request for longer than 60
minutes.
Display indication when protection is active -
number 7 (flashing)
6.6 High discharge line temperature protection (HDT)
The controller monitors the discharge line temperature
(inputs DT1, DT2) and should it rise above 110°C the
compressor will be stopped.
When high temperature protection is activated the
compressor is stopped for at least 3 minutes. The
compressor is allowed to restart after 3 minutes
provided that the discharge line temperature has fallen
to below 100°C.
If three consecutive trips occur then the unit will be
“locked out”. The trip counter is reset to 0 when there
has been no compressor run request for longer than 60
minutes.
Units with a variable compressor or digital scroll
compressor will automatically reduce capacity before
the discharge temperature rises close to the threshold.
Display indication when protection is active -
number 9 (flashing)
6.7 Compressor lock-out
Certain faults (as outlined in the preceding paragraphs)
can cause the unit to be “locked out” if they occur
three consecutive times while the compressor-run
request has remained active. When a unit is locked out
the compressor is not allowed to start until the lock-
out is manually reset. Lock-out protects the unit from
repeatedly starting the compressor when a serious fault
exists that requires the attention of a service technician.
When a unit is locked out the alarm relay output (NO7,
NC7) will be active.