28. | Put setup switch | Ð | Ð | 29 | |
29. | Jumper R and W/W1 thermostat terminals. | Ð | Ð | 30 | |
30. | Does RED LED2 turn back ON? | 7 | 31 | Ð | |
31. | Install isolation relays in the W/W1 and Y/Y2 circuits per Fig. 5 in Appendix B or replace thermostat. | Ð | Ð | 8 | |
32. | Was RED LED2 ON before you started Step 1? | 34 | 33 | Ð | |
33. | Solid YELLOW LED3 indicates furnace is in high fire and solid GREEN LED4 indicates furnace is in | Ð | Ð | 8 | |
low fire. | |||||
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34. | Check outdoor unit contactor. Failure to pull in can cause excessive current draw on |
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circuit. This can be intermittent and may require extended operation to repeat problem. Isolating | Ð | Ð | 35 | ||
| outdoor unit may solve problem. (See Fig. 6 in Appendix B.) |
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35. | Check thermostat wire gage between furnace and outdoor unit. It is recommended that AWG No. |
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18 | Ð | Ð | 14 | ||
| ft, use AWG No. 16 wire. |
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36. | Observe operation of furnace through a 20 minute heat cycle. Try to pinpoint where in cycle RED | Ð | Ð | 37 | |
LED2 turns ON. | |||||
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| Go to step indicated below if RED LED2 turns ON when 1 of the following events occur: | Ð | Ð | Ð | |
| · When gas valve is energized. | Ð | Ð | 38 | |
37. | · When HSI is energized. | Ð | Ð | 39 | |
| · When | Ð | Ð | 38 | |
| · RED LED2 never turns ON. | Ð | Ð | 40 | |
38. | Replace gas valve. | Ð | Ð | 8 | |
39. | Isolate humidifier with a separate | Ð | Ð | 14 | |
40. | Observe operation of furnace through a 4 minute cooling cycle. Does RED LED2 turn ON? | 41 | 47 | Ð | |
41. | Disconnect all thermostat leads from furnace control board. | Ð | Ð | 42 | |
42. | Put setup switch | Ð | Ð | 43 | |
neously until RED LED2 turns OFF. | |||||
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43. | Put setup switch | Ð | Ð | 44 | |
44. | Reconnect only outdoor unit to Y/Y2 and Com terminals on furnace control board. | Ð | Ð | 45 | |
45. | Jumper R and Y/Y2 thermostat terminals. | Ð | Ð | 46 | |
46. | Does RED LED2 turn back ON? | 34 | 31 | Ð | |
47. | Go to page number indicated in Index for CLEANUP AND |
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persists on an intermittent basis, replace furnace control board. If problem still persists on an inter- | Ð | Ð | INDEX | ||
| mittent basis after replacing furnace control board, contact your distributor. |
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RED LED2 FLASHINGÐIndicates line voltage polarity is reversed.
STEP | ACTION | YES | NO | GO TO | |
1. | Turn power off, remove blower access panel, and disconnect all thermostat leads from furnace con- | Ð | Ð | 2 | |
trol board. | |||||
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2. | Turn power on and depress door switch. Use a piece of tape to hold switch closed. | Ð | Ð | 3 | |
3. | Is RED LED2 flashing? | 6 | 4 | Ð | |
4. | Replace furnace control board, date code 9405 or later. | Ð | Ð | 5 | |
5. | Go to page number indicated in Index for CLEANUP AND | Ð | Ð | INDEX | |
6. | Do you have 120 vac across L2 and chassis ground? | 7 | 8 | Ð | |
7. | Line voltage polarity is reversed. Fix problem. | Ð | Ð | 5 | |
8. | Replace furnace control board. | Ð | Ð | 5 | |
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