![Bosch BSS250-21-2 Installation And User Manual Download Page 39](http://html.mh-extra.com/html/bosch/bss250-21-2/bss250-21-2_installation-and-user-manual_52808039.webp)
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PWR light ON, pump not
running and
yet is sunny outside.
PUMP light is OFF.
TOPOUT light is OFF.
a. Sensor not mounted properly.
b. Water not hot enough yet.
c. Roof sensor over 140C.
a. Check sensor is thermally
bonded to
Solar Panel outlet.
b. Check temperatures of Roof
and Inlet,
they need to be greater than the
difference
programmed for pump ON.
Wait.
c. Normal Operation, Pump
disabled.
Pump will not operate and yet is
sunny
outside.
PUMP light is OFF.
TOPOUT light is ON.
a. Topout temperature
exceeded.
a. If Tank temperature greater
than Topout
programmed value then is
working
normally.
Pump running continuously.
a. Pump is cavitating.
b. Special installation.
c. Settings incorrect.
d. Airlock.
a. If pump is making noise like
stones
passing through it then it is
cavitating. See
SolaStat Plumbing Issues.
b. Special installation where
long pump on
times are normal.
c. Check programming.
d. Air relief valves not
installed/functioning.
Pump runs at night.
FROST light is ON
a. Frost outside Pump runs at
night.
a. Normal operation.
FROST light is OFF
a. System is reverse
thermosiphoning
a. The non-return valve is not
fitted
correctly or is faulty.
Hot Water drops significantly
overnight
yet little or no draw off of hot
water by
the user.
a. System is reverse
thermosiphoning.
b. System is in an excessive
frost
area.
c. Tank losing heat.
a. The non-return valve is not
fitted
correctly or is faulty.
b. Discuss non frost sensitive
options with
provider.
c. Install better insulation on hot
water tank.
TOPOUT Light Flashing Fast
a. Wire to Roof sensor broken.
b. Roof Sensor Damaged.
c. Roof Sensor below -40C.
a. Repair wire.
b. Replace Roof Sensor.
c. Check Outside Temperature.
TOPOUT Light Flashing Slowly
a. Wire to Roof Sensor shorted.
b. Roof Sensor Damaged.
c. Roof Sensor above 150C.
a. Repair Wire.
b. Replace Roof Sensor.
c. Check Collector has water in
it.
FROST Light Flashing Fast
a. Wire to Inlet sensor broken.
b. Inlet Sensor Damaged.
a. Repair wire.
b. Replace Inlet Sensor.
FROST Light Flashing Slowly
a. Wire to Inlet Sensor shorted.
b. Inlet Sensor Damaged.
a. Repair Wire.
b. Replace Inlet Sensor.