26
PMAX
: Flow rate in l/min
Setting range: 0.5 ... 100.0
Default setting: 6.0
9
Note!
Parameter
FMAX
in only available if parameter
SEN
is
set OFF or if no Grundfos Direct Sensor™ is activated.
19.24
Thermal energy metering with Grundfos Direct
Sensor™ sensor VFD
Thermal energy metering can be activated in all systems using
Grundfos Direct Sensor™ sensors. To implement thermal energy
metering, proceed as follows:
− Activate the Grundfos Direct Sensor™
VFD
in parameter
GFD
− Setting range for
VFD
Grundfos Direct Sensor™ in param-
eter
SEN
− Specify the desired heat transfer medium and percentage
of anti-freeze in the parameters
MEDT
and
MED%
SEN
: Digital sensor for measuring flow rate (only if GFD = 12, 40
or 40 F)
Selection: OFF, 1, 2
Default setting: 2
Type of flow rate measurement:
OFF
fixed flow rate (flow meter)
1
Grundfos Direct Sensor™ in flow
2
Grundfos Direct Sensor™ in return
19.25
Assignment of thermal energy metering
sensors
MEDT
: Heat transfer medium
Setting range: 0 ... 3
Default setting: 1
Heat transfer medium:
0
water
1
propylene glycol
2
ethylene glycol
3
Tyfocor® LS / G-LS
MED%
: Anti-freeze percentage in % by vol. (MED% is not dis-
played if MEDT is set to 0 or 3)
Setting range: 20 ... 70 %
Default setting: 45 %
Note!
If system layout 3 has been selected and the
OHQM
func-
tion activated, thermal energy metering is interrupted as soon
as the 3-way valve switches to excess heat dissipation mode. If
thermal energy metering is based on a Grundfos Direct Sensor™,
it is not interrupted.
19.26
Drainback function
Note!
Drainback systems require other system components such
as a drainback tank. The drainback function must only be acti-
vated if all the necessary system components are installed.
The drainback function is only available for system layouts 1 and
2.
A drainback system allows the heat transfer medium to drain
back into a drainback tank when solar charging is not in pro-
gress. The drainback function starts to fill the system when solar
charging begins
SEN
1
2
OFF
System
layout
SM
SR
SM
SR
SM
SR
1
GFD
S4
S4
GFD
S1
S4
2
GFD
S4
S4
GFD
S1
S4
3
GFD
S4
S4
GFD
S1
S4
If the drainback function
ODB
is activated, the pump runs at
maximum speed throughout filling time
tFLL
to fill the system
with heat transfer medium from the drainback tank. At the end
of
tFLL
, speed is reduced to the minimum speed setting nMn.
After this, the deactivation conditions are ignored for the set
stabilisation period tSTB to avoid the system switching off to
soon.
