L8100A,B,C Aquastat
®
CONTROLLERS
60-2336—3
8
1
2
3
VR8440 VALVE
TERMINALS
3
2
ECO SWITCH
CONTROLLER
L8100A,B
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
FACTORY-INSTALLED WIRES, DO NOT REMOVE.
SELECTED MODELS HAVE 3/16 AND 1/4 IN. TAB TERMINALS.
M4757
TH-TR
TH
TR
L1
(HOT)
L2
1
25V
25V
TH-R
TH-W
MV
MV/PV
PV
GND
S86H
GND
Fig. 16. Four-terminal L8100B manual reset hookup with S86H and VR8440.
OPERATION AND CHECKOUT
Operation
When tank temperature rises past the setpoint, the liquid fill in
the sensing element expands and activates the snap-acting
switch, closing the gas valve. When the water temperature
drops below the differential, the switch opens the gas valve
and the burner begins heating the water. The ECO switch will
break the circuit to the Powerpile® millivolt generator or 24
Vac main valve before the water temperature rises to 210
°
F
(99
°
C).
The second element of the L8100B,C is located at the top of
the tank. These two elements sense the average temperature
in the tank. If a stacking condition begins, the L8100B,C will
close the valve before the top tank temperature becomes
excessive.
Adjusting
Adjust the control point to agree with the manufacturer’s
recommendations. To adjust, remove the cover and set the
scale to the desired control point (see Fig. 17).
SETPOINT SCALE
CONTROLLER
TERMINALS
ECO SWITCH TERMINALS
(ON L8100A,B ONLY)
M4760
Fig. 17. Internal view of the L8100.
