The thermostat controls the temperature of water in the front boiler.
* The thermostat rests in a well in the coffee boiler.
* The thermostat contains a bellows filled with a thermal fluid that expands and contracts depend-
ing on the surrounding temperature.
* As the water heats in the coffee boiler it causes the fluid in the
bellows to expand, which pushes up a piston.
* When the piston rises far enough, it actuates a switch, which turns
off the thermostat and cuts power to the heating element.
* When you adjust the screw on top of the thermostat you are
adjusting the distance the switch is from the piston.
Turning clockwise increases the distance causing the
piston to travel farther to actuate he switch, therefore in-
creasing the temperature of the water in the boiler. Turning
counter-clockwise has the opposite effect. Shorter distance
to travel and therefore lower water temperature.
* Each 1/4 turn of the adjustment screw represents approximately a 3 degree F change in temp-
erature.
Heating Element
Each boiler has a heating element.
* The element for the steam boiler receives electrical power
from the pressure switch.
* The element(s) for the coffee boiler(s) receive electrical
power from the thermostat(s).
* As electrical power is applied to the element it heats up the
surrounding water in the boiler.
* To determine amp draw, divide wattage by incoming voltage.
Pump Motor
The pump motor turns the pump, which boosts existing water pressure. The LM uses several types
of motors.
* All motors feature an internal thermal overload protector.
* Some pump motors are equipped with a capacitor, which provides the initial “push” required to
start the motor.
*Over time the capacitor may weaken causing a slight delay in the motor turning on after the group
is activated.
Gasket
Solenoid Coils
The solenoid valves operate by energizing an electromagnetic coil that causes a valve piston to
move downward, opening the valve.
* Test the coil by turning the machine off and disconnecting the wires, then read between the left
and right terminal with a multi-meter. The reading of a good coil should read between .7K
ohms and .8K ohms.
Power from Switch
Power to Switch
Adjustment Screw
Bellows
Thermostat
