Dettson AMT100B34-IM2, Installation Instructions Manual

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2.4) LIMIT CONTROL CHECK
The Limit Control is factory adjusted according to Figure 1.. After the
furnace has been in operation for at least 15 minutes, restrict the
return air supply by blocking the filters or closing the return registers
and allow the furnace to shut down on high limit. The burner will shut
OFF and the main blower should continue to run.
Remove the restriction and the burner should come back on in a few
minutes.
For Year Round Air Conditioning
The furnace is designed for use in conjunction with cooling
equipment to provide year round air conditioning. The blower has
been sized for both heating and cooling; however, the fan motor
speed may need to be changed to obtain the necessary cooling
airflow.
Heating
The blower speed is factory set to deliver the required airflow at
normal duct static pressure.
Cooling
The blower speed may be adjusted in the field to deliver the required
airflow for cooling, as outlined in Table 5, according to the selected
model.
Constant Blower Switch
This furnace is equipped with a constant low speed blower option.
Whenever the room thermostat is not calling for heating or cooling,
the blower will run on low speed in order to provide air circulation. If
this constant blower option is not desired, the rocker switch on the
side of the control box can be used to “turn off” this feature.
2.4.1) Fan-Limit adjustment and blower regulator
Modification of the “FAN ON” and “HI” limit settings on the Fan-Limit
can cause malfunctioning of the furnace and result in premature
wear of the heat exchanger.
CAUTION
Modification of the factory set limits will void the
warranty.
Figure 1: Fan-limit adjustment and blower regulator
DNS-0355 Rev A
1 Limit “FAN OFF” 90 ° F
2
Limit “FAN ON”
110 ° F
3 Limit “HI”
Model: AMT1-SM1 & AMT1-IM2
170 ° F
Model: AMT2-IM2 190 ° F
Model: AMT2-SM3
180 ° F