9 FUNCTIONS
9.1 Recording hours of operation
The device stores the number of hours of operation of the following in permanent memory:
• hydraulic pump
• compressors
It is precise to within one minute.
Hours of operation may be displayed by entering the appropriate menu with the label Ohr (refer to menu structure).
The whole value is displayed if it is less than 999 hours; if it exceeds this value, the hundreds of hours will be shown and
the decimal point will appear:
For example, 1234 hours will be displayed as follows:
To set the number of hours to zero, hold the DOWN key (refer to keys) down for two seconds while displaying the number
of hours of operation.
In the event of a power failure, the latest fraction of an hour recorded is set to 0, so that duration is rounded down
9.2 Defrosting
The defrost function is active in heating mode only.
It is used to prevent ice formation on the surface of the external exchanger,
which can occur in locations with low temperature and high humidity.
It will considerably reduce the machine’s thermodynamic performance, creating a risk of damage to the machine.
Defrosting is enabled if:
• it is enabled by the parameter (Pa d01= 1)
• there is at least one condensation probe (Pa H07, for input AI3= 1 or 2, or Pa H08, for input AI4= 1)
• the reversing valve is present
Defrosting may be controlled on the basis of temperature or pressure, depending on how the machine is configured in Pa
H49.
Defrost start and stop commands are given on the basis of condensation probe readings and parameter settings, as
described below:
9.2.1 Defrost start
• If condensation temperature/pressure drops below Pa d02 (Defrost start temperature) and the compressor
is ON, the response counter starts (Pa d03, defrost response time).
• When duration Pa d03 has expired, the instrument begins defrosting.
• At this point, if Pa d06 (compressor…valve delay time) = 0, the compressor will stay on. If not, the control
illustrated in the diagram below will be applied:
SD: defrost start COMPR: compressor
RV: reversing valve Pa d06: compressor/valve delay time
This delay prevents liquid from flowing back into the compressor.
Diagram
35.48
35
Pa d06
ON
OFF
ON
OFF
COMPR
RV
Pa d06
SD
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