Limit Control Checkout:
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 main burners will shut OFF and the main blower and combustion blower should continue to run. Remove the restriction and the burners should come back on in a few minutes.
Flame Rollout Switch:
This unit is equipped with two (2) manual reset flame- rollout switches that protects against improper venting of the flue gases from the heat exchanger due to blockage causing heat (or flames) to "rollout" into the burner box from the heat exchangers, either safety device will activate and shut off power to the automatic gas valve before there is damage to the furnace. The loss of power to the gas valve will shut off the gas burners. Should this occur, it will be necessary to determine the cause of the rollout, correct the condition that caused it, and reset the
The furnace should be allowed to
The switches are located behind the front access door. Remove front access door from the furnace and reset by pushing in the button in the middle of the switch (between the two wire connections - See Figure 16). Very little force is required to push the reset button, and a "click" should be heard when the switch resets.
Figure 16
FLAME ROLLOUT SWITCH
Pressure Switch Check:
To check the operation of the pressure switch vent safety control, remove the vent adaptor from the combustion blower. Place the furnace into operation for high fire. Gradually cover up the blower outlet; the furnace should first drop to low fire and with further restriction of the opening, the main burners should shut OFF. Remove the restriction and the unit should relight. Replace the vent adaptor and reseal the opened joints as required.
The operational checkout is now complete. Be sure to adjust the thermostat to the desired setting and inform the homeowner how to operate the furnace system before leaving the job site.
If the pressure switch activates to shut the furnace down, the vent system must be checked and cleared. Failure to do so may result in serious bodily harm or nuisance furnace shutdown and/or a hazardous condition that may lead to property damage, personal injury or death.
20571201 | Issue 0527 | Page 22 of 28 |