Instruction manual V 2.3
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PWM 230 - PWM 400 - PWM 400/7.5
Instruction manual
5.1.3.5
FL: Setting the min. frequency
With FL we set the min operating frequency of the pump. FL values may range between 0 Hz and 60% of
Fn; for example, if Fn =50 Hz, FL can be chosen between 0 and 30 Hz.
FL is reset to the default each time we set a new Fn value.
5.1.3.6
Ft: Setting the low flow rate threshold
The parameter “Ft” allows to set a minimum flow rate under which the PWM turns off the pump.
5.1.3.7
CM: Role exchange policy in booster sets
When two PWM units form a booster set the two electro pumps roles (leader or booster, as defined in note
below) can be exchanged according to two different policies.
Note: Irrespective of the value of "Ad" (primary or secondary PWM), the PWM that regulates will be called
“PWM leader” (module the frequency) while the PWM that works only at the highest frequency will
be called “PWM booster”.
The admissible values for the exchange policy CM are: 00 and 01.
-
CM = 00: The primary PWM is always the regulation leader and the secondary PWM will be active as
a booster (if Eb = 2) or as spare device (if Eb = 1). If the secondary machine remains unused for 23
hours, it becomes the leader until it has accumulated one minute of regulation (a washing of the impeller
is performed).
If during operation the leader electro pump is unable to satisfy the user and the secondary
electro pump is configured as a booster (Eb = 2), the latter will work at maximum frequency,
while the leader PWM will continue modulating rotation frequency according to the user
demand.
If the user demand decreases, the booster machine is turned off, while the leader machine
continues regulating.
- CM = 01: The primary and secondary PWM act as leader or as booster alternatively. The roles are
exchanged each time the leader PWM goes into stand-by mode or after 2 hours of continuous activity.
If during operation the leader electro pump is unable to satisfy the user and the secondary
electro pump is set as a booster (Eb = 2), the latter will work at maximum frequency, while the
leader PWM will continue modulating rotation frequency according to the user demand.
If the user demand decreases, the leader machine goes in stand-by mode and becomes the
booster (i.e. off), while the booster machine becomes the leader (and starts regulating at
variable speed).
Setting of the enable parameter of the booster operation Eb is described in sec. 5.1.2.7 “Eb: Enable
booster“.
For each of the two exchange modes, if one of the machines fails, the other becomes the leader and carries
out regulation at constant pressure up to its maximum available power.
5.1.3.8
AE: Enabling the anti-frost/anti-block function
This function helps to avoid mechanical blocks in case of long inactivity or in case of low temperature and is
obtained by running the pump.
When the anti-frost function is enabled, if the PWM measures a temperature that is too low, with a risk of
frost, it automatically starts running the electro pump at low speed. Keeping water in movement reduces frost
risks in the pump. In this way breaking risks due to ice are reduced in the PWM also, thanks to power
dissipation. Vice versa, if the temperature is in a safe range, a long inactivity can prevent the mechanical
parts from operating or cause formation of residuals inside the pump; to avoid this an anti-block cycle is
performed every 23 hours.