Specifications
12. Troubleshooting
 WARNING
Apart  from  those  inspection  items  specifically  outlined  as  “HOMEOWNER”,  any 
maintenance or repair  must only  be completed by Authorized Persons.  The solar collector 
warranty  may  be  void  if  non-Authorized  Person  attempt  to  maintain  or repair  the  solar 
collector  or  associated  system  components.  The  solar  system operates at  high pressure 
and high temperature and can result in damage to both property and personal  injury if not 
correctly operated and maintained.
CL = Specific to Closed Loop DF = Specific to Direct Flow 
Problem
Cause
Solution
Pump not ON during 
good solar radiation 
conditions
Temperature sensors not working 
properly
• Check that sensor is installed correctly
• Check that sensor wire is not damaged
• Check sensor Ohm reading with Ohm to °F chart in 
controller manual
Pump not ON during 
good solar radiation 
conditions
Controller settings incorrect
• Check controller is set to AUTO operation
• Check maximum tank and collector settings 
Pump not ON during 
good solar radiation 
conditions
Controller Max Temp setting has 
been reached
• Check maximum tank and collector settings
Pump cycling ON and 
OFF during good solar 
conditions
Partial shading of collector
• Check collector location for shading
Pump cycling ON and 
OFF during good solar 
conditions
Excessive system flow rate
• Adjust restrictor screw on flow meter
• Reduce pump speed (select slower speed)
Pump cycling ON and 
OFF during good solar 
conditions
Controller settings incorrect
• Check if differential (dT function) is correct, dTMin may 
be set too high, reduce to 2
°
C / 4
°
F
Pump always ON even 
during minimal solar 
radiation conditions
Insufficient flow rate
• Check flow gauge for proper flow rate
• Adjust restrictor screw on flow meter
• Check that all isolation valves are open
Pump always ON even 
during minimal solar 
radiation conditions
Air lock in piping system
• (DF/CL) Release air from air vent on highest point
• (CL) Purge system of air by following Fill and 
Pressurize procedure described in section 7.9.
Pump always ON even 
during minimal solar 
radiation conditions
Sensor location too low
• T2 sensor (bottom tank) should be slightly above the 
level of the solar flow port. If below the flow port, the 
pump may run continually even when there is no solar 
heat.
Pump always ON even 
during minimal solar 
radiation conditions
Controller settings incorrect
• dTMin may be set too low. Increase 2-3
°
 especially if 
closed loop system. 
Pump running at night
Controller settings incorrect
• (DF) Check that freeze protection setting is correct. 
Intermittent circulation is freezing conditions is normal. 
Ensure pipes are well insulated.
Pump running at night
Poor Sensor Reading
• (DF) Tank S2 sensor not getting accurate reading
Fluid dumping from 
pressure relief valve on 
pump station
Faulty pressure relief valve
• Replace pressure relief valve
Fluid dumping from 
pressure relief valve on 
pump station
Faulty expansion tank
• (CL) Replace expansion tank on pump station
Fluid dumping from 
pressure relief valve on 
tank
Excessive tank temperature
• Check Maxtemp Tank1 setting of controller
• Check tank sensor (T2) operation
Fluid dumping from 
pressure relief valve on 
tank
Faulty expansion tank
• Replace expansion tank on potable water side










