Goodman Furnace not staying lit

[ScubaSteve]

I haven't been able to find the answer I'm looking for so far so I thought I'd try asking about my problem directly.

I have a Goodman furnace that I tried to start up a few weeks ago for the first time since last winter. The furnace will light without an issue and the indicator light will remain on (meaning everything is fine) but after a few seconds the flame will go out. This process is repeated three times before the system shuts down and the indicator light begins to slowly and continuously blink. I can't find an error code to correspond with this pattern of blinking.

I read that the a flame that burns for a few seconds and goes out indicates a bad reading on the flame sensor so I replaced it but the problem remains. If it helps, the furnace is on a concrete slab in a dirt floor basement. Any advice is greatly appreciated.

[HayZee518]

is there any make up air being fed into the basement? have you had this problem last year's heating season?

[ScubaSteve]

The furnace worked without any issues last year. I'm not sure if the unit has a system of drawing in any makeup air but it doesn't seem like it and there's no other ventilation down there.

[HayZee518]

do me a favor, go and check out this site I stumbled upon. Perhaps your issue is explained here.
Goodman Janitrol Furnace Ignitors

[ScubaSteve]

I've already spent some time on that site and I'm yet to find my problem. It is a very helpful site though.

[HayZee518]

OK, I been reading your post. That site indicates the pilot device but you said you replaced the millivolt generator [ flame sense] so we can eliminate that. the millivolt generator is connected into the main valve pilot solenoid. The bulb end that screws into the main valve should be wrench tight. So the next thing I'm looking at is the main valve and/or pilot valve. I realize that to try to purchase a new valve to replace the existing is expensive, but that may be the only alternative. you willing to buy one?
another site - this one has the main valve:

http://americanhvacparts.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=gv-goodman

[ScubaSteve]

Sorry if I'm mistaken but aren't the millivolt systems only for furnaces utilizing pilot lights? My furnace uses an ignitor. Obviously I have a flame sensor but from what I understand it doesn't work the same way as the millivolt generators. My flame sensor goes to a connector that leads to the control board. Also, the link you provided does not seem to carry goodman/ janitorial gas valves at all.

[HayZee518]

OK, granted a millivolt system may not be what you have. A flamerod for a furnace functions more/less the way one in a monitor heater does. It has an ac potential on it when it is cold. when a flame is on, the gas in the air between the electrode and ground becomes ionized and so conducts producing a dc voltage which is monitored by the electronics. there's a timing circuit in the flame sense or flamerod circuit. if a flame isn't detected then the system shuts off the main gas and locks out. if there is a flame then the circuit allows the main valve to open fully. sorry about that link, I'm trying all my resources.