ADJUSTING HEAT ANTICIPATOR
!CAUTION
The adjustable heat anticipator WILL BURN OUT if 25 VAC is applied directly to the thermostat by shorting out the primary control during testing. This may cause personal injury and/or property damage.
This thermostat is equipped with an adjustable heat anticipator and was preset at the factory to provide satisfactory operation of the heating system under normal conditions. If additional adjustments are necessary, they may be made as follows (see fig. 9):
1.Remove thermostat cover.
2.If heat cycle is too long, set heat anticipator to a slightly lower dial setting (1⁄2 division).
3.If heat cycle is too short, set heat anticipator to a slightly higher dial setting (1⁄2 division).
4.Replace thermostat cover.
CALIBRATING THERMOSTAT
This thermostat has been carefully adjusted at the factory and should not require recalibration.
Due to environmental conditions, during normal operation there may be a few degrees of difference between the indicator setting of the thermostat and actual room tem- perature. If the disagreement is appreciable, however, first make sure that the thermostat is properly located and leveled. Then, if recalibration still seems necessary, pro- ceed as follows:
!CAUTION
To prevent electrical and/or equipment damage, disconnect electrical power to the system until recalibration is complete.
1.The anticipator’s heat may adversely affect thermo- stat recalibration. To prevent this, disconnect electri- cal power to the thermostat at the furnace, main fuse, or breaker box.
2.Move temperature adjustment lever to a setting about 5° above room temperature.
3.Remove thermostat cover. Slip 7⁄32” wrench onto hex nut beneath bimetal. While holding temperature ad- justment lever stationary, turn hex nut clockwise until mercury shifts to the right end of the tube (see fig. 10).
4.Move temperature adjustment lever to lowest setting.
5.Replace thermostat cover. Wait 10 minutes for bi- metal temperature to stabilize. Do not stand near the thermostat during this period, as your breath and body heat will affect bimetal temperature.
6.Move temperature adjustment lever to correspond to actual room temperature. Then remove thermostat cover.
7.Slip 7⁄32” wrench onto hex nut. While holding tempera- ture adjustment lever stationary, turn hex nut counter- clockwise until mercury just barely shifts to the left end of the tube (see fig. 10).
8.Replace thermostat cover and set temperature ad- justment lever to desired temperature. Turn on elec- trical power to system.
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Arrow points to the |
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| Move this lever to |
matched current rating |
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| adjust heat |
of the primary control |
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| anticipator |
Figure 9. Anticipator adjustment
7⁄32” Calibration
wrench
Bimetal
Temperature 
adjustment
lever
Figure 10. Calibrating thermostat
If you need further information about this product, write to us at:
Emerson Electric Co.
9797 Reavis Road
St. Louis, MO
Attn: Technical Service Department
