Bryant 355MAV Troubleshooting Manual page 27

39. Will main burners ignite and stay on?
40. Do you have combustion pulsations?
41. Make sure perforated disks are in combustion-air vent inlet.
42. Check pressure tubing going to gas valve air pressure fitting for kinks.
43. Remove gas valve air pressure fitting and check gas valve for blockage.
44. Ensure vent and combustion-air pipes are not reversed.
45. Check burner orifice size and alignment.
46. Add restriction to combustion-air pipe or lengthen it a few feet if possible.
47. Jumper R and W2 thermostat terminals on furnace control board.
48. Do you have combustion oscillations in high fire?
Fault Code 41
BLOWER OUTSIDE VALID SPEED RANGE—THIS FAULT INDICATES 1 OF THE FOLLOWING:
• Blower motor speed cannot be maintained within 10% of calculated speed over a 30-sec period.
• Blower motor speed is less than 250 RPM or greater than 1300 RPM for more than 10 sec.
STEP
Turn power off, remove blower access panel, and disconnect R thermostat lead from furnace con-
1.
trol board.
2. Turn power on and depress door switch. Use a piece of tape to hold switch closed.
3. Jumper R and W/W1 thermostat terminals on furnace control board.
4. Observe operation of furnace for next 8 minutes or until fault occurs.
5. Does Fault Code 44 flash twice followed by Fault Code 41?
After about 10 minutes of operation, furnace will lock out and flash Fault Code 12. Go to page num-
6.
ber indicated in Index for Fault Code 12.
7. Does only Fault Code 41 flash?
8. Does a different fault occur?
9. Go to page number indicated in Index for fault code flashed.
Go to page number indicated in Index for CLEANUP AND STARTUP
10.
INSTRUCTIONS.
11. Does blower motor suddenly stop 10 sec before fault is signaled?
12. Turn power off and disconnect jumper wire across R and W/W1 thermostat terminals.
13. Put setup switch SW-4 labeled EMER. HEAT in ON position.
Turn power on and wait several sec, then jumper R and W/W1 thermostat terminals on furnace con-
14.
trol board.
15. Check connectors PL3, PL10, PL11, PL12, PL13, B1, and B2.
16. Does motor operate intermittently in response to connectors and wires being moved?
17. Fix problem.
18. Does blower motor suddenly stop?
Replace entire blower motor or blower control module attached to the blower motor. If you replace
→19.
the blower control module go to step 26. If problem still persists on an intermittent basis after re-
placing blower motor or blower control module, contact your distributor.
20. Replace furnace control board.
21. Turn power off and disconnect jumper wire across R and W/W1 thermostat terminals.
Check connectors PL3, PL10, and PL13 for possible intermittent connection of ORANGE and VIO-
22.
LET wires.
23. Are ORANGE and VIOLET wires from PL3 and PL13 making good contact?
Replace entire blower motor or blower control module attached to the blower motor. If you replace
→24.
the blower control module go to step 26.
Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS. If problem
persists on an intermittent basis, replace entire blower motor or blower control module attached to
→25.
the blower motor. If your replace the blower control module go to step 26. If problem still persists on
an intermittent basis after replacing blower motor, contact your distributor.
ACTION
—27—
12 17 —
41 47 —
— — 42
— — 43
— — 44
— — 45
— — 46
— — 12
— — 48
41 12 —
YES NO GO TO
— — 2
— — 3
— — 4
— — 5
6 7 —
— — INDEX
11 8 —
9 25 —
— — INDEX
— — INDEX
12 21 —
— — 13
— — 14
— — 15
— — 16
17 18 —
— — 10
19 20 —
— — INDEX
— — 10
— — 22
— — 23
24 17 —
— — 17
— — INDEX