Custom Search
|
|
|
||
 FIGURE 2-41
A Draindown System
Using Three Solenoid
Valves
Special control valves are of a rotary or spool valve type. Both are typically used on
small systems only, due to their limited flow capacity. Their basic principle of
operation is identical to the three solenoid valve system. (Figure 2-42)
Draindown control valves usually include a check valve to prevent nighttime heat
loss by reverse thermosiphoning. This heat loss can occur on nights warm enough
for the collectors to be filled.
FIGURE 2-42
An Automatic
Draindown Control
Valve
OPERATION
2.7 COMPONENT OPERATION
45
|
 
|
|
|
||
