ADD DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED
TO CONTROL LOW VOLTAGE EQUIPMENT
TO CONTROL LINE VOLTAGE
SETTINGS AND ADJUSTMENTS
When adjusting the fan and limit set point levers
(Fig. 10), hold the scalepale dial to keep it from turning
and straining the sensing element.
Move each indicator lever to the control point
recommended by the burner or furnace manufacturer.
Use gentle finger pressure.
FAN SETTING ADJUSTMENT
1. Move the FAN OFF lever to the temperature at
which the fan is to stop to prevent circulation of cool
2. L4064B - Move the FAN ON lever to the
temperature at which the fan is to come on.
MANUAL FAN SWITCH
For constant fan operation, push the FAN switch
button in. For fan to cycle automatically, pull button
LIMIT SETTING ADJUSTMENT
These controllers have a limit stop which prevents
the limit indicator lever from being adjusted beyond
the equipment manufacturer's specifications.
1. Push the small end of Limit Adjust Tool
(196722) through hole in scaleplate (located at
caution marking) to depress the stop disc not more
than 1/16 in. (1.6 mm) to release stop lock (Fig. 10).
Stop disc is on back of scaleplate.
2. While depressing the stop disc, insert the long
end of Limit Adjust Tool next to limit stop (Fig. 10)
and move the stop to desired setting. If the L4064 is
a replacement control, high limit stop setting should
be the same as that of the control being replaced.
(Move stop clockwise
limit stop adjust tool.
3. Set the LIMIT OFF lever to the temperature at
which the high limit switch is to open to stop the
burner. If the high limit stop has been properly set,
the LIMIT OFF lever should be as high as the stop
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN, 55422
© Honeywell 2006 Printed in Canada
Fig. 9 - A: Limit in low voltage circuit.
B: Limit in line voltage circuit.
C: Limit in line voltage circuit without jumper.
to lower the setting,
to raise it.) Then remove the
As the plenum temperature rises, the bimetal sensing
element of the control wraps and mechanically makes
FAN OFF SET
FAN ON SET
HOMEOWNER: THIS IS A "SAFETY STOP". DO NOT ALTER
Fig. 10 - Changing the high limit stop.
the fan contacts (at the FAN ON temperature setting).
During normal operation, the call for heat end before
the LIMIT setting is reached, and the fan contacts break
as the plenum temperature falls and the FAN OFF
setting is reached.
If the call for heat continues until the temperature in
the plenum rises to the LIMIT setting, the bimetal
element will mechanically break the limit contacts and
de-energize the gas control circuit.
When installation is complete, disconnect the fan
motor circuit at the L4064. Turn on power and set
thermostat to call for heat. Burner should come on and
limit controller should shut burner off when plenum
temperature reaches the limit set point. Turn off power,
recconnect the fan switch, turn on power and again set
thermostat to call for heat. Fan should come on when
plenum temperature has reached fan-on setting.
TO RELEASE STOP,
PRESS STIFF WIRE
DO NOT ROTATE - HOLD DIAL
WHEN SETTING POINTERS
LIMIT SET POINT LEVER
(FACTORY-SET AT 200