Trane UX1B040A9241A Installer’s Guide, Burner Box Temperature Limit Device, Abnormal Conditions

BURNER BOX TEMPERATURE LIMIT DEVICE

All models are equipped with a manual reset tempera- ture limit located on the burner box. In case of exces- sive temperature, the limit will open and cause the cir- cuit to open which shuts off all flow of gas.

ABNORMAL CONDITIONS

1.EXCESSIVE COMBUSTION PRESSURE (WIND IN EXCESS OF 40 M.P.H.) VENT OR FLUE BLOCK-

AGE

If pressure against induced draft blower outlet be- comes excessive, the pressure switch will open and shut off the gas valve until acceptable combustion pressure is again available.

2.LOSS OF FLAME

If loss of flame occurs during a heating cycle, or flame is not present at the sensor, the flame control module will close the gas valve. The flame control module will then recycle the ignition sequence, then if ignition is not achieved, it will shut off the gas valve and lock out the system.

3.POWER FAILURE

If there is a power failure during a heating cycle, the system will restart the ignition sequence auto- matically when power is restored if the thermostat still calls for heat.

4.GAS SUPPLY FAILURE

If loss of flame occurs during a heating cycle, the system integrated control module will recycle the ignition sequence, then if ignition is not achieved, the integrated control module will shut off the gas valve and lock out the system.

5.INDUCED DRAFT BLOWER FAILURE

If pressure is not sensed by the pressure switch, the contacts will remain open and not allow the gas valve to open, therefore the unit will not start. If failure occurs during a running cycle, the pressure switch contacts will open and the gas valve will close to shut the unit down.

6.CONDENSATE DRAIN BLOCKAGE

If the condensate drain is blocked, either by debris, improper draining, or by freezing condensate, the pressure switch will sense the accumulation of con- densate in the furnace drain pan. The pressure switch contacts will open and remain open, not al- lowing unit operation. The unit will not operate un- til the condensate drain has been cleared, and the condensate flows freely.

7.RESET AFTER LOCKOUT

When the integrated control module has shut the system down and gone into lockout, the system must be manually reset before the unit will restart. To reset, turn the system power off, then on, then off and then on again within 30 seconds. This may be done at the unit’s power source or at the ther- mostat. The system will not reset unless the proce- dure off-on-off-on is completed within 30 seconds.

Installer’s Guide

8.RESET AFTER BURNER BOX LIMIT SHUT- DOWN

If the furnace shuts down, one thing that can be checked is the burner box temperature limit switch. It is located on the bottom of the burner box. The vent and combustion air inlet terminations should be checked for blockage. If blockage exists, clear

the problem and then the reset button may be de- pressed. If there is no blockage of the termina-

tions, the limit switch must be reset by a qualified servicer.

Carbon monoxide, fire or smoke can cause serious bodily injury, death, and/or property damage.

A variety of potential sources of carbon monoxide can be found in a building or dwelling such as gas-fired clothes dryers, gas cooking stoves, water heaters, furnaces and fireplaces. The U.S. Consumer Product Safety Commis- sion recommends that users of gas-burning appliances install carbon monoxide detectors as well as fire and smoke detectors per the manufacturers installation in- structions to help alert dwelling occupants of the pres- ence of fire, smoke or unsafe levels of carbon monoxide. These devises should be listed by Underwriters Labo- ratories, Inc. Standards for Single and Multiple Station Carbon Monoxide Alarms, UL 2034 or CSA Interna- tional Standard, Residential Carbon Monoxide Alarming Devices, CSA 6.19

NOTE:

The manufacturer of your furnace does not test any de- tectors and makes no representations regarding any brand or type of detector.

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