Thermo Products USDT2004 - Manual (Page 12)

12
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.
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/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
larm 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
1 SHORT Short circuit in sensor 1 wiring
2 SHORT Short circuit in sensor 2 wiring
1 OPEN Disconnection in sensor 1 wiring
S
A