I have a 10 year old Bryant model 376CAV (92,000 btu) downflow furnace. The electronic igniter will glow at the appropriate time and ignite the flame but the flame will cut out shortly after the ignitor shuts off. This happens repeatedly through many cycles/attempts to maintain ignition.This has happened in the past (about 4 years ago) and vacuuming any sediment out of the relief box seemed to cure it (possibly the furnace is pressure sensitive and a partial block in the relief was to blame?). This is not the case this time as I have shop vac'd the relief box again to no avail unless possibly there is more blockage than I thought. You can only get so far into the relief box with a shop vac. Any ideas and/or suggestions on what could possibly be the problem would be appreciated. Thanks.
Rob

Check the self test feature. How many blinks.

http://www.ackleysheetmetal.com/brya...s/00002248.pdf

Look on inside door for the blink code.

Another possibility.

Clean flame sensor see this link for location.

http://www.gogeisel.com/geiselonline...CAV_Gas_OM.pdf

Another possibility

Bulletin United Carrier Corporation Technologies Carrier Residential Engineering SMB 96-0023 Subject: FURNACE CONTROL BOARD RESISTOR SOLDER JOINT FAILURES 04/17/96 UNITS AFFECTED: CAC: 58MXA, 58MCA, 58WAV, 58PAV, 58RAV BDP: 350MAV, 340MAV, 395CAV, 376CAV, 383KAV, 373LAV PAYNE: 480BAV, 481BAV, 490AAV Resco/Eventemp/Cobra: GB1AAV, GB3AAV SITUATION: A resistor solder joint failure mode has been identified on the following control boards used in the subject gas furnace. Affected Controls: HK42FZ004 (Obsolete) HK42FZ007 (Obsolete) HK42FZ008 (RCD Replacement) HK42FZ009 (Production, Open faced control board) HK42FZ011 (Production, Covered control board) Refer to Table 1 for the affected serial number ranges of the subject units. Table 1 CAC MODELS SERIAL NO. RANGE BDB MODELS SERIAL NO. RANGE 58MCA 3193A - 4595A 340MAV 3193A - 4595A 58MXA 3193A - 4595A 350MAV 3193A - 4595A 58PAV 1594A - 4595A 383KAV 1594A - 4595A 58RAV 1594A - 4595A 373LAV 1594A - 4595A 58WAV 1594A - 4595A 395CAV 1594A - 4595A 58ZAV 1594A - 4595A 376CAV 1594A - 4595A PAYNE MODELS SERIAL NO. RANGE RESCO/EVENTEMP SERIAL NO. RANGE /COBRA 480BAV 1594A - 4595A GB1AAV 1594A - 4595A 481BAV 1594A - 4595A GB3AAV 1594A - 4595A. For further information on replacing these controls please contact your supplier."