Fig. 3
Inside a thermostatic mixing valve
disturb the supply and watch it recover
MIXED OUTLET
feeds one port of Fig. 2
→ Fig. 2
WAX ELEMENT SITS IN THE MIXED STREAM
SETPOINT ADJUSTER
ROD BEARS ON THE ADJUSTER
OVERLOAD SPRING
pushes hot open
HOT SEAT
SHUTTLE
COLD SEAT
HOT SUPPLY
132 °F
COLD SUPPLY
52 °F
116
84
100
40 s ago
now
outlet temperature · shaded band is ±2 °F
—
100.0
valve shut · no flow
Hot in
132
Cold in
52
Setpoint
−
100 °F
+
Disturb
Flush a toilet
Cut the cold
Outlet
100.0
°F
Hot port
62
%
Cold port
38
%
Flow
1.9
gpm