Instruction manual
Solarflo - Solar Thermal Domestic Hot Water System 27
5.0 Fault finding
YES
Pump symbol on controller rotates
but pump does not operate
Pump fault
Replace pump
Is controller to 
pump connection correct 
and secure
YES
Is the pump siezed
NO NO
NO
YES
Can the impeller be 
revolved using a screwdriver 
after removing the air 
bleed screw
Free impeller and replace
air bleed screw
Check connections and
rectify as necessary
YES 
Displayed temperatures on controller 
vary greatly over short time intervals 
Controller fault 
Replace controller 
Are sensor cables 
laid alongside mains 
voltage cables 
NO 
Have sensor cables 
been lengthened with 
unshielded cable 
NO 
NO 
Do sensors give 
correct temperature 
v 
resistance readings 
YES 
YES 
NO
Are sensor
connections correctly
made
YES
Sensor fault
Replace sensor
Use shielded cable to extend 
sensor cable lengths 
Seperate sensor cables from 
mains cables (Min. 50mm 
recommended) or use 
shielded cable 
Rectify sensor connections










