Thermo Products USDT 2004B - Manual (Page 12)

12
rost and overheating protections - Pump operation can be manipulated by the user in
both collector stagnation and frost conditions. This set-up is possible in System Guard,
SGUARD, Men domain.
Overheating protection (CET) – 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. USDT 2004
will take over the normal operation after the temperature decreases to an acceptable working
temperature, shown as
=. This feature (ON) can be disabled by user to (OFF). Factory setting
is 260
o
F to stop the pump. The pump starts again at 230
o
F. Customer in field can change these
settings.
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
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 disabled at the factory and
displayed as (OFF).
min
= Pump runs below this temperature (factory setting 35 F)
min ? Pump stops above this temperature (factory setting 39 F)
tart functions - The Circulation pump can be programmed to start on a low insolation
level. The Start function feature is useful when heat transferred to the collector sensor is
not fast enough for an 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.
START
Start function screen
ON Enable start function
OFF Disable start function
If this feature is selected, following parameters must be adjusted for proper operation:
GBS
Pyranometer port designation (radiation monitoring sensor port)
1 Sensor 1
2 Sensor 2
3 Sensor 3
-- Manual input in next step
INS Radiation threshold in W/m
2
CIRC Pump runtime in seconds
INT Maximum interval time in second
FLU Number of flushes
The following example activates the circulation pump at 200 W/m
2
and runs it for 15 seconds. If
rT condition is met within the time period, the pump stays on.
INS
20 CIRC 15
F
S