Thermo Products USDT2004 - Manual (Page 11)

11
START Starts pump at pre-set insolation (solar radiation intensity)
ALARM Enables/Disables protection functions
BTU Energy calculation and setting
ensor Designation – USDT 2004 accepts two different sensor types or a reference
value . User can program a constant reference temperature instead of a sensor output.
The factory-preset sensor is the thermistor (KTY 10) type. The KTY 10 tank sensor,
white wire, should be used in a conditioned environment and will not be permanently damaged up
to 360
o
F.
Selection:
S1
Sensor 1 (collector outlet) selection
S2 Sensor 2 (collector inlet) selection
S3 Sensor 3 (tank) selection
Designation:
PT
PT 1000 sensor (1000 O at 0
o
C, not available in US market)
KTY Thermistor sensor (2000 O at 25
o
C)
250 250
o
F reference temperature
- 4 - 4
o
F reference temperature
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. The impedance characteristics of
sensors temperature dependencies are represented in the following table:
T
0 10 20 25 30 40 50 60 70 80 90 100°C
R(KTY) 1630 1772 1922 2000 2080 2245 2417 2597 2785 2980 3182 3392
Ω
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 collector 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 ? T, the
S
F