I'm working on a forced hot air furnace that's in a basement that got flooded and the furnace was only on 2-4 so it looks like the whole blower motor and control board transformer got flooded. I responded to a no heat call today check the unit the unit won't do nothing, it has power coming from service switch it has power going to the board it has 24v going to board tstat but won't operate when calling for heat I checked pressure switch checked for countinity when I sucked on the tube it was fine I jumped it nothing happened I checked all limits switches roll outs etc everything good. I think I have a bad board it has some green corision on the board as well before I order a new I just wanted a professional opinion thanks

You say you have 24v at themostat strip on board? If so, then this eliminates the fuse on the control board. Set the thermostat to call for heat and then check for 120 at the board going to your draft inducer. This is just to make sure you draft inducer has not failed. If you have 120v at the inducer and inducer doesn't start, let me know.

That said, if your board was immersed in water, it's a pretty good bet that its fried. Flooded furnace, usually means replacing board, and you may also have a ruined blower motor. Not to mention transformer(but if you have 24v to board, your trans if fine.

I would start by replacing the control board. This will have to be done before you can check other operations of furnace. Good luck and let me know what you find.

Your right the fuse was not blown and the idm is not getting no power from board

You said you have 120 suppling board, yes. If this is true, you have to replace board. Definitely first step.
Let the home owner know what you are dealing with, and see if they want to have you replace part after part, or would they think about looking into a knew furnace. (Some people don't like the idea of having a gas fired applience that has been flooded.) If they just want you to fix existing furnace, start with the baord, and see if this doesn't fix all of your problems. Just let the homeowner know that there may be other problems you will have to deal with after the board is replaced. Im hoping the board is the final sollution. Good luck and please keep me posted.

Thanks ill change it and let u know