Lennox Hearth EPIC40 - Manual (Page 22)

 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Operating Options
Your stove comes equipped with an “On/Off” rocker switch
used to turn the burner on and off while the pilot light is
on. The switch is a round rocker switch located behind the
main control panel door.
A millivolt wall thermostat, or a remote control, can be used
to supplement the rocker switch. The gas valve is powered
by millivolts generated by the pilot assembly. This millivolt
system is very sensitive to electrical resistance, therefore,
make sure all connections are tight, clean and free from
corrosion. Do not splice any millivolt wires. Consult the
table below to determine the proper gage of wire for the
thermostat or wall switch connections. This table refers
to the total length of the wire (out to the switch and back).
The thermostat must be a millivolt type. A 24-volt furnace
thermostat will not work. Never hook up household current
- 120 Volts - to the millivolt system. It is not recommended
to hook up any more than two switches to the stove (for
example a rocker switch and a wall thermostat). Additional
switches may affect the system resistance and increase the
chance of the burner not igniting.
Millivolt Control Schematic
Follow the instructions included with the thermostat or
remote control for wiring. The thermostat, remote control
and rocker switch will turn the burner on and off indepen-
dently. Be sure to set the rocker switch to the “Off” position
when using the thermostat or remote control and set the
thermostat or remote control to the lowest temperature when
you wish to use the rocker switch only, otherwise one may
override the other.
Millivolt Control System
This stove operates on a millivolt control system. As such,
no additional power supply is needed for the stove to heat.
The pilot assembly contains a thermocouple that, when
heated by the pilot flame, generates electricity (millivolts-
mV=1/1000 of a volt) which opens a valve allowing gas to
continue flowing to the pilot assembly. The pilot assembly
also contains a thermopile that, when heated by the pilot
flame, generates electricity that flows to terminal #1 (labeled
TPTH) on the gas valve. When the electricity is conducted
from terminal #1 through the on/off switch, thermostat, or
receiver of the remote control to terminal #3 (labeled TH)
on the gas valve, the main burner will ignite.
Thermopile
ON/OFF Rocker Switch,
Thermostat, or Remote
Thermostat
Piezo Igniter
Thermocouple
Pilot Gas Line
Sparker
Pilot Hood
Pilot Assembly
Gas Inlet
Pressure Taps
Terminal 3 Terminal 1 Terminal 2
CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper
and dangerous operation. Verify proper operation after
servicing.
Figure 33
Thermostat Wire
Wire Size Maximum Length
 Gage 00 Feet
4 Gage 64 Feet
6 Gage 40 Feet
8 Gage 5 Feet
0 Gage 6 Feet
Gas Valve
Wiring Terminals