EVCO S.p.A.
c-pro 3 OEM HRV | Application handbook ver. 4.0 | Code 144CP3OHE404
page 111 of 138
This function, when the machine is turned on, activates all the hot water coils present for a modulated duration based on the outside temperature, from 0 minutes
when the temperature exceeds the setpoint (parameter
Pb12
) to a maximum (parameter
Pb14
) when the temperature falls below the setpoint minus a differential (pa-
rameter
Pb13
). During this period, the fans will remain switched off and the external air and warm-up dampers will stay closed.
To disable the function, simply set the maximum time defined by the parameter to 0
Pb14
.
8.10
Electric coils
It is possible to configure one of the treatment coils which uses "digital" electric heating elements (activated via digital output - from 1 to 5) or modulating elements
(activated via analogue output). Mixed situations are also possible.
8.10.1
Coil with ON-OFF heating elements (digital)
Based on the number of heating elements that have been configured (parameter
PG06
), the adjustment differential is divided proportionally (parameters
Pb01/Pb22/Pb24
depending on the cases).
It is possible to enable the rotation of the heating element steps using the parameter
Pb07
. This rotation is LIFO type and is based on the comparison the number of
operating hours of the individual steps. When starting up, the step with the least number of operating hours will be prioritised, while when switching off, the step with
the greatest number of hours will take precedence.
If it necessary to choose between steps with the same number of operating hours, a FIFO type rotation is activated, to guarantee rotation even if there are the number
of hours present.
A certain amount of time (parameter
Pb20
) must elapse between each heating element start-up/switch-off in order to avoid simultaneous peaks.
8.10.2
Coil with modulating heating element
To regulate the heating elements by modulation, set parameter
PG06=1
.
On opening, the output stays at 0% until the request reaches a higher value than the parameter
Pb25
, then assumes the request value. On closing, the output as-
sumes the request value until it reaches a higher value than parameter
Pb25
, then it is maintained at the value of
Pb25
until request is lowered to 0%.
8.10.3
Coil with modulating heating e 1 on/off step
A sawtooth regulation has been implemented to manage the modulating heating elements together with the digital steps.
In this case, the heat regulator needs to know the ratio between the maximum power that can be supplied by the modulating heating element (parameter
Pb04
for
coils 1 and 2 and
Pb16
for the re-heating coil) and the power supplied by the ON-OFF heating element in order to correctly divide the proportional band
(
PB=PB
MOD
+PB
ON-OFF
). The power that can be supplied by the on-off heating element can be easily calculated using the formula PB
ONOFF
= 100-PB
MOD
;
For example, if the modulating heating element supplies 60% of the power and the ON-OFF heating element 40%, the proportional band will be divided so that this
power ratio is respected:
PB
MOD
=60% x PB, PB
ON-OFF
=40% x PB
.
The minimum power that can be supplied by the modulating heating element is defined by parameter
Pb25
for coils 1 and 2 and by
Pb17
for the re-heating coil.
As the temperature detected by the heat regulation probe decreases, the power requested increases in proportion (
P
REQ
) to the heating elements. The actions per-
formed by the heat regulator depending on the required power level reached, are the following:
1st heating element
2nd heating element
3rd heating element
5th heating element
4th heating element
Differential
SetPoint
T. Regulation
NZ
