EVCO c-pro nano CHIL - Manual (Page 131)

C-PRO NANO CHIL AND C-PRO MICRO CHIL – APPLICATION MANUAL
Pag. 131
6.17.9 Operating limit management (heat pump)
When the external air temperature falls to particularly low levels, it may no longer be convenient or
sufficient to heat using the heat pump. The Limit set point PC17 on external temperature is used to
disable the heat pump, enabling instead a relay output for start-up authorisation of a boiler or
heating-coil set. Reactivation happens when the external temperature exceeds the limit set point plus
a configurable Limit differential PC72. The parameter Operating limit management PC70 also
offers the choice – once the auxiliary output has been activated – whether to switch OFF the
compressors too, or to leave them ON.
In order to enable this function, the external temperature probe (PH24) must also be enabled.
In addition, parameter Auxiliary relay position for operating limit HA04 also needs to be set to a
value other than zero; if zero is left unchanged, the relay is not controlled.
6.17.10Function for chilling/heating on demand
If it has been enabled by parameter Control-on-demand enable PC80, this function requires a
dedicated remotely-mounted temperature sensor (usually installed inside an accumulation tank);
once a given set point has been reached (in chilling operation, Summer control-on-demand set point
PC81; in heating operation, Winter control-on-demand set point PC82), and after a Control-on-
demand delay PC85, this function determines the activation of the circulating pump and
compressor, to carry out the required function with the typical selected thermoregulation (i.e. return
or delivery temperature regulation). The units turns itself OFF once the accumulation tank has been
satisfied, i.e. once it has reached the Summer control-on-demand set point PC81 minus a Summer
control-on-demand differential PC83 (if in chilling mode), or the Winter control-on-demand set
point PC82 plus a Winter control-on-demand differential PC84 (if in heating mode).
Limit set p. PC71
OFF
ON
Ext. T
Diff. PC72
Winter set point PC82
OFF
ON
Accum. T
Diff. PC84