15
Water Connections continued-
2.
For a drainback solar heating system, refer to Figure 4. The solar water heater connection labeled “FROM
SOLAR COLLECTOR” should be piped to the solar collector supply piping. Mount the pump making sure the
flow arrow points toward the water heater. The use of shut-off valves and unions are recommended for future
service convenience. Pipe and fittings between the solar collector and solar water heater must be ¾” diameter or
larger. The drainback tank must be located at a level above the pump and water heater. A site glass should be
installed either on the tank or in piping at the same level as the tank to determine fluid level within the system
when not heating. Verify that all check valves are removed from the solar heating system including components
such as the pump. Also verify that all heating fluid drains from the collectors and piping through a suitable pitch
in the lines.
Figure 4 - Solar Collector Piping in Drainback Installation
FILL SOLAR COLLECTOR SYSTEM
1.
Fill solar heating system appropriately with water or a FDA approved propylene glycol/water mix.
2.
Verify pump flow and direction. In a closed loop system, purge all air from the collector/water heater piping.
3.
Check system for leaks. Repair as necessary.
a.
In a closed loop system, check for leaks when flow is stopped and the operating pressure is maintained.
