Potterton eurocondense four 125 kw, Installation, Operation And Maintanance Manual, Page: 99 / 148

HW (2461) and Switching diff off min HW (2462)Switching diff off
max HW
Sd Switching difference off
Sd1 Switching diff off max CHs, Switching diff off max HW
Sd2 Switching diff off min CHs, Switching diff off min HW
Sd3 Switching diff on CHs, Switching diff on HW
t Time
Ti Actual temperature
To avoid unnecessary switch off during transient effects the switch-off dif­
ference adapts dynamically depending on the temperature profile (see
fig.).
Delay heat req special op (2470)
The heat request during special operation (chimney-sweep function, con­
troller stop, manual operation) is sent to the burner delayed by the time set
here. In this way slowly opening mixers can already start up before the
burner goes into operation. Thus a boiler temperature that is too high can
be prevented.
Pressure switch shutdown (2500)
This function checks the static water pressure with the aid of the connec­
ted water pressure switch. Depending on the option set ( Start prevention
or
Lockout position
) a start prevention or lockout position is carried out
with a corresponding diagnosis.
A closed water pressure switch releases the startup of the burner control
and the actuation of the pumps. A start prevention or lockout position is
triggered with the pressure switch open.
The pump actuation is also locked for protection against dry running. If the
water pressure increases again and the switch closes again, this is auto­
matically cancelled again with a start prevention and the pump actuation is
released again.
Gas energy metering (2550)
This parameter is used to switch gas energy metering on or off. The coun­
ter values are not deleted during this process.
Gas energy metering correction (2551)
The gradient of the linear approximation function is adapted here.
Value < 1: Leads to lower gas energy metering.
Value > 1: Leads to increased gas energy metering.
A value of 1 means there is no change compared to the approximation
function stored.
9.2.12 Cascade
Lead strategy (3510)
The heat generators are switched on and off acc. to the set lead strategy
taking the specified output range into account. To switch off the effect of
the output range, the limits must be set to 0% and 100% and the lead
strategy to late on, late off.
Late on, early off: Additional boilers are switched on as late as possible
(output range max) and switched back off again as soon as possible
(output range max). I.e. as few boilers as possible in operation or short
running times for additional boilers.
Late on, late off: Additional boilers are switched on as late as possible
(output range max) and switched back off again as late as possible (out­
put range max). I.e. as few switching on and off processes as possible
for the boilers.
Fig.38 Switching difference
t
Sd
Sd1
Sd2
Sd3
RA-0000079
Ti
Ti
9 Settings
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