92
If this fault causes more than 5 shutdowns in 24 hours:
- Corresponding circuit shut off.
- Fault output on
- Circuit fault LED on console lit steady.
D) Compressor driver fault:
Terminals 2-3 on terminal bloc J5 on the CONNECT 2 board receive signals indicated faults on the Danfoss compress driver.
Only alarms that shut down the compressor are received.
When contact 4-6 on the driver opens, the driver is in alarm mode. The following message should appear on the CONNECT 2 console:
This function is activated 5 seconds after the power is turned on.
- Compressor shut off
- Fault acknowledged automatically
- Fault stored in memory in case of a mains power failure
- Fault saved in fault memory
- Relay in On position
- Compressor driver fault relay on relay board in On position
- General fault LED lit steady
25 DEFROSTING OF THE EVAPORATOR COILS
CIAT has developed an optimised frosting control system.
Called DEGIPAC (P159 = optimised), it defrosts the evaporator
coils only when frost has actually formed on them instead
of based on the frosting time (P159 = fixed). It does so by
continuously monitoring the difference in temperature between
the coil and the outdoor air. If this difference is abnormally high, it
turns on the defrost cycle. DEGIPAC makes it possible to
continue producing hot water for hours during cold, dry weather
without having to defrost the coils. As a result, it improves the
seasonal COP.
Parameter P161 is used to advance (if P161 < default value) or
delay (if P161 > default value) the start of the defrost cycle.
- Defrost cycle for reversible machines with split circuits (where
P2 = 3 and P11 = split)
The defrost cycle is turned on when any of the following occur:
The discharge temperature is too high (see discharge protection
in heating mode);
Ice is detected on the coil by the sensors on the coils. In this
case, defrosting is performed by only one circuit at a time to
ensure a minimum supply of hot water for the system;
A difference in pressure, where HP > LP +13.5 for 120 seconds if
INVERTER compressors are used.
- Defrost cycle for reversible machines with intertwined or mixed
circuits (where P2 = reversible air-to-water and P11 = intertwined
or mixed). In this case, defrosting is performed by both circuits at
the same time.
Defrosting is possible only when the water return temperature is
high enough to ensure that the heat exchanger will not freeze
when the cycle is reversed.
Defrosting is triggered by the low-pressure sensor that reads the
lowest value.
- If this temperature is too low (< P52 + 8 K if there are 2 compressors per circuit and < P52+16 K if there is 1 compressor per circuit) and
there is no way to increase it, the unit will shut off, save the fault in memory, and display the following message:
- If the temperature can be raised via the second circuit, a boiler or electric auxiliary heaters, the following message will appear:
- If this temperature exceeds 26°C, the circuit rises to maximum
temperature before the four-way valve reverses and stays at
maximum temperature during defrosting in order to minimise the
defrosting time.
- If this temperature drops below 26°C, the circuit rises to
maximum temperature before the four-way valve reverses and
lowers in temperature during defrosting to prevent frost from
forming on the heat exchanger.
Note: During the defrost cycle, CONNECT 2 continuously monitors the temperatures and pressures to prevent frost from forming on the heat
exchanger and thus turning on the protections.
This is why the fans may turn on during a defrost cycle.
26 HOURLY PROGRAMMING
26.1 Presentation
This function allows the weekly management of liquid chillers by selecting:
- 6 programming stages (maxi).
- 6 holidays zones (maxi).
C I R C U I T x O F F
C P D E L T A P F A U L T
M A C H I N E O F F
O U T T E M P . T O O L O W
C I R C U I T x
B E I N G D E F R O S T E D
C I R C U I T x O F F
D E F R O S T I N G I M P O S S I B L E
W A T E R T E M P . R I S I N G
F O R D E F R O S T I N G
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