These heating thermostats are specially designed for use on self-
generating systems. They should never be used on line or low
voltage A.C. circuits.
exterior Wall — The thermostat may be mounted on an exterior
wall above the heater if it is located in the same stud space as the
vent tubes and is a minimum of 6" (152mm) above the heater.
interior Wall — The thermostat should be installed on an inside
wall away from the unit but in the same room.
note: Use 16 gauge wire to prevent excessive loss of millivolts.
Proper operation depends on a good pilot flame. The flame must
cover the top of the thermopile. Cleaning of the pilot orifice and
burner may be required due to spiders.
system check
A millivolt meter is required to check the system. The millivolt
readings should be:
• Across the thermopile terminals, 400-450 millivolts with ther-
mostat OFF.
• Across the thermopile terminals, 150-250 millivolts with ther-
mostat ON.
• Across the thermostat wires at the valve, less than 30 millivolts
with thermostat ON.
• Across the thermostat wires at the thermostat, less than 5 mil-
livolts with thermostat ON. (Strong winds, dirty pilot and low
pressure will reduce readings.)
Piezo Pilot Ignitor Instructions
Depressing the piezo ignitor button completely causes a spark to
occur at the pilot. This is a substitute for a match which requires
opening the pilot hole cover.
To light the pilot, it is important that the electrode be 1/8" (3mm)
from the thermopile. The spark must occur at the point the burner
flame hits the thermopile. The end of the electrode will be red hot
with the pilot on.
On a new installation with air in the gas line, it is suggested that a
match be used. The match will light the pilot faster than the piezo
under this condition.
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tHerMostat location
Figure 6
12433-11-0709