I don't remember, but is a G16 the one with the gas valve and ignition control thta are combined into one unit?? If it is good luck, there is a kit from Lennox to replace this, but it can get pricey.
Keep us posted, I'd like to see if it was the ventor motor, or pressure switch??
D D Boyer, the some of the first generation had what you talking about gas valve and ign. in one m/n (G16Q*E-***-1).
J Starzy, In Georgia, I wouldn't spend the money for a 90%+, but NJ maybe a different story. If you can repair for a moderate price, I would. I've seen those heat exchangers (G8, G10, G12, G16, G17, G20's) last 15 to 30 years (your age may vary)where has it been located (basements good, crawlspaces bad), how much rust on the burner.
The cracks in a Duracurve Heat Exchangeer are most likely in the upper back in the curve (they are really hard to see with a flashlight alone and sometimes it looks cracked but isn't). Also they can be found in front right above burners and pilot.
Everything mentioned here could be the problem, however remote, it is possible the pressure switch is causing this, jump it out and see if flame stays established.....
Where in central NJ?
The G16 should not be venting into the Brick chimney without a chimney liner... And Is the brick chimney exposed (outside wall) or is it an inside chimney (center of house or such that not exposed to the cold on any sides?
I have seen G16 furnaces installed improperly with the chimney terminations and in most cases the excessive rust and condensation caused by this improper installation was the cause of many problems (with inducer motor and pressure switches)
Just curious about your chimney setup.....
[Edited by jimhvac86 on 01-28-2005 at 07:17 PM]
Chimney is only exposed for 1-1/2 stories above garage roof line. There is a 6 inch rectangular liner on the furnace side and a 12 inch liner on the fireplace side. Both have meshed caps to keep the varmints out.
The HWH penetration to flue in basement is above the furnace...my error in previous message.
Tech is suppose to swap parts and assess today. The new real Lennox inducer and pressure switch assembly were dropped of with me yesterday.
What was wrong with the draft motor? Was it shutting down?It was either running or not. Also you can jump out the pressure switch in a manner to allow it to fire to determine if it is the switch or not.
Conclusion to Short Cycling
Gas Co. Tech measured draft in flue with old inducer blower and demonstrated how draft kept reducing; at first with inducer, then flame engaged then fan motor. It went below what I think was 4.5 (something like that with meter that looked like VOM). This kicked the pressure switch and shut down the flame.
He installed the new inducer motor and kept the old switch in place...inducer engaged, then flame, then blower....ALL OK...flame stays on just fine, no cycling...apparently inducer blower was bad. He replaced the pressure switch with the new one anyway and the unit operates fine. We examined heat exchager and firebox and all looked good. Flame was also consistent through all cycles.
Thanks to all for help...