INTERESTING FACTS ABOUT MY DOMESTIC SOLAR HOT WATER SYSTEM
Operating the system with the pump set to speed 2 (as recommended in manual) uses much more power than using speed 1 for no noticable difference in system performance (i.e. temp of water in cylinder.)
Speed 1 = 40 watts Speed 2 = 60 watts
Examples of Pump operation in May :-
Weather was bright / sunny all day
Pump operated 135 times, average run time 1 minute, total run time of 2 hours 18 minutes.
Temp in bottom of cylinder at 7 am = 50 degsC at 7.30 pm = 67 degsC.
Weather wet all day varied from drizzle to heavy rain.
Pump operated 51 times average run time 50 secs, total run time of 1 hour 14 minutes.
Temp in bottom of tank at 7 am = 45 degsC at 7.30 pm was 50 degsC
Data recorded from a 20 tube Thermomax system facing South West into a 195 litre Hot water cylinder. Emeter battery monitor connected to computer recorded power in/out of battery powering pump & controller
See power speed comparison page for graphs of different pump settings.