If the fluid level never drops, the charging pump needs priming, or is faulty. If the
fluid level drops for a while, then stops, and no fluid is coming out of the discharge
hose, the pump is not strong enough to push fluid to the top of the collectors.
It is a good idea to turn the solar control to the "On" position while charging, to help
the process and purge air from the pump.
Make sure any other pump that will also be turned on is either
disconnected or filled with fluid, so it is not running while dry.
After the system has been completely filled, and all the air has been purged, no
additional bubbles will be seen. Run the charging system for at least another ten
minutes. The fluid should be completely free of surface bubbles, and have no sign
of milkiness. A few extra minutes spent can save a return trip to recharge the
Close the drain fitting, and allow the charging pump to build the pressure up about
five pounds higher than the level indicated in Table 5-5.
Once the pressure is reached, close off the fill valve, and turn off the charging
pump. Leave the pump and hoses connected.
Turn off the system control if it was turned on. Open the gate or ball valve, if one
was used in the fill/drain assembly.
After filling a glycol loop, test a small sample of the fluid. Note the pH, glycol
percentage and reserve alkalinity in the operation and maintenance record for that
system. Information on testing is in Section 3.1.6 in the inspection chapter.
After the system has been off for about ten minutes, briefly open the air vent on
each array of collectors. A small amount of air may be present. If more than a brief
hiss of air comes out, charge the system for at least ten minutes more and check
the vents again.
If the charging process seems to be going well, but air still shows up in the system,
check the suction hose and fittings on the charging pump for leaks. A jet pump
can suck in air and still pump fluid.
5.2 REPAIR PROCEDURES