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Sensor wires can receive electromagnetic pulses, which can result in a wrong
temperature reading. The USDT 2004 reads sensor values every 50 ms. It can
bundle several readings and process their average.
AV 1
Sensor 1 average
AV 2
Sensor 2 average
AV 3
Sensor 3 average
The numbers of samples can be programmed from 4 to 20.
rost and overheating protections -
Pump operation can be manipulated
by the user in both collector stagnation and frost conditions. The set-up is
possible in System Guard,
SGUARD,
domain.
Overheating protection –
The Circulation pump may not be powerful enough to
circulate the heat transfer fluid in the solar loop with air pockets. User can
program the pump to stop at a desired
maximum
temperature, shown by
?
symbol, to protect the pump. The USDT 2004 will take over the normal operation
after the temperature decreases to an acceptable working temperature, shown
as
=
. This feature is disabled at 299
o
F set point.
Frost Protection –
Frost protection in the sun-belt region is provided by
circulating water in the solar loop when freezing conditions exist. Regardless of
the temperature difference D elta T, the circulation pump runs when the collector
temperature is below a programmable
minimum
temperature, shown by
=
symbol. The pump stops as soon as the temperature in the solar loop reaches a
safe region programmed by the
?
symbol. This feature is also disabled at the
factory by entering - 4
o
F.
min
=
Pump runs below this temperature
min
?
Pump stops above this temperature
tart functions -
The Circulation pump can be programmed to start on low
insolation level. The Start function feature is useful when heat transferred
to the collector sensor is not fast enough for early start; especially when the
collectors are flat mounted.
The enabled start function runs the pump at a given solar radiation or
programmed temperature difference. The feature is disabled at the factory.
F
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