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 oF.
min= Pump runs below this temperature min? Pump stops above this temperature
Start 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.
START | Start function screen |
ENABL | Enable start function |
DISAB | Disable start function |
If this feature is selected, following parameters must be adjusted for proper operation:
SENS | 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/m2 | |
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/m2 and runs it for 15 seconds. If rT condition is met within the time period, the pump stays on.
INS 20
CIRC 15
Alarm functions - User can enable the alarm function of the USDT 2004 in the ALARM screen. Status of sensors and circulation pump can be viewed if alarm function is active.
A | ON | Alarm function enable |
A | OFF | Alarm function disable |
The status of the system can be monitored in the Stat Mode only if the corresponding feature is active. The following example shows a system condition with a circulation problem:
OT | OFF | Overheating feature disable |
OT | OK | No overheating |
1SHORT Short circuit in sensor 1 wiring
2SHORT Short circuit in sensor 2 wiring
1 OPEN | Disconnection in sensor 1 wiring |
12