Amana Air Command 80

[lordrandy]

My furnace works good most times.  then one time it doesn't . I turn the system off, either by turning t-stat all the way down for a few seconds or by turning the switch off by the furnace.  works good, maybe all night, then in the morning it stops working. Any suggestions?

[dkpd1581]

With so little information to go on, some of the more common problems causing intermittent heating might be:

1. Over limit switches tripping and auto resetting but the board registers the fault and locks the unit out until you reset via the power switch or T-stat.

2. Bad flame sensing device (hot surface ignitor/flame proof, bad thermocouple/flame sensor)

3. Exchanger cracks or obstruction (in flue and/or exchanger).

4. Defective limit switches.

5. Bad gas valve.

6. Improper gas pressure setting.

7. Defect in control wiring low volt.

8. Defect in blower motor, inducer, high volt system.

9. Dirty or maladjusted pilot assembly.

These are in no particular order of precedence and may be one, a combination, or none of the above.  The preceding items assume a gas furnace since it references 80 for 80% in the name.  Give all the information you may have starting with model, serial, wire diagram if one is available, age of unit, location of unit, type of heat system gas/electric, type of ignition system, natural gas or LP, induced or natural draft.