The Solar Boiler module reservoir is filled with heat transfer fluid
(40/60 propylene glycol USP/distilled water) when it leaves the factory.
When the Solar Boiler pump is in operation it draws glycol from the reservoir
and pumps it through the solar collectors. This reduces the level in the
reservoir from 15-16" down to 2 - 8". The level can be checked
with the 24" dipstick supplied with the Solar Boiler. Check the level
after the pump has been operating at full speed for at least 5 minutes
and make sure the PRV is removed from the vent tube. Use a DC power supply
that can deliver up to 3 amperes of current to run the motor directly.
Set the voltage on the power supply to 15 volts for this operation.
To improve the performance of the Solar Boiler we recommend that the level
of glycol in the reservoir be increased to 12", measured when the
pump is in full-speed operation. One inch on the dipstick represents
0.25 liter of heat transfer fluid. Four inches represents 0.25 US
gallon. Determine how much fluid must be added to bring the level in the
reservoir to the 12" height in the fill tube and place this amount
of 40/60 propylene glycol/distilled water in a container. With the PRV
removed from the 1/4" vent tube, add the required amount of the 40/60
mixture of propylene glycol USP/distilled water through the 1/2" fill
tube. Use a funnel that fits snugly inside the fill tube. The pump must
be operating at full speed while the reservoir is being filled so that
the solar collector loop is completely filled with glycol. Check the level
of glycol in the fill tube once more to make sure that it is at the 12"
mark. Reconnect the PRV to the vent tube.
Do not replace the original knurled hose cap on the fill tube. Use
the "new" brass cap fitted with the air valve (similar to the
typical tire air valve). With a tire pump/air mattress pump - equipped
with a quick disconnect for the air valve - pump air slowly into the Solar
Boiler module, with the pump running, until you can hear the motor start
to slow down a little bit. Remove the air pump and check the pressure with
a tire gauge. It should be 5-10 psi if the system is cold and 10-15 psi
with the system hot. Add/release air as required to obtain the required
The PRV may allow a small amount of fluid to escape the first time
the system gets hot after charging with fluid. Do Not Refill if only a
small amount escapes. Place a one-liter plastic container under the PRV
to capture any fluid that may be expelled from the Solar Boiler.