90 + gas furnace. inducer full of water

Most likely one of two issues is occurring. Either the inducer fan is not providing enough draft because it is either spinning too slowly or the impeller is damaged, or the pressure switch that the inducer motor air flow is supposed to activate is not operating properly. If the pressure switch fails to activate, the furnace will not open the gas valve and fire the ignition believing that there is not sufficient draft the vent the combustion gases.

I would check the vacuum switch and make sure its not sticking it is the switch that is hooked up to your fan with a small 1/4 inch hose.

Could be several causes.
1. Blockage on piping
2. Water in inducer housing slowing down inducer impeller
3. Condensate trap for furnace clogged up.
4. Inducer motor going bad.
5. Leak in vacuum hoses or not connected.
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The codensate drain is the white 3/4 inch pipe comimg off the side of the furnace. The inducer is the motor above the burners. Sometimes if they drain is clogged it will back up and leak, other times it will leak behind the inducer, and should ne removed and silicone applied to the gasket of the motor

This unit is designed to condense, I suspect that the drain is blocked by some debris. Remove the larger hoses from the burner box and inducer motor and blow into them to clear any debris. Plug the end of the hose so you don't force water into either the inducer or burner box. Make sure that there is a vent on the drain just as it leaves the furnace cabinet. This will assist the drain to work properly and not cause the condensation to go up in the pressure switch hose.

nope, condensate drain clogged

code 31 indicates pressure switch did not close or reopened during the heat cycle....1st thing to check is the inducer motor,,this is a small motor that turns a small blower wheel that draws the exhaust gases through the furnace and blows them into the vent pipe....1st locate the inducer assembly,,most easily identified by the small plastic fan blade that cools the inducer motor as it runs..1st turn off tstat and turn off furnace power switch..then turn on furnace switch,then set tstat to heat,set the temp above room temp by 5 degrees...remove the furnace front cover,locate the inducer motor,,if it isnt turning,but is warm or hot after a minute or so,likely the inducer motor is bad..if it isnt turning and isnt warm after 1 minute,then likely the main control board is bad,,not turning the inducer motor when it should,,,,,if the inducer motor is running,,then the pressure switch isnt closing,, could be a bad pressure switch but more likely there is a problem with the venting...some possible problems that would cause the pressure switch not to close in an 80% eff furnace [metal vent pipe] are: [1] a blockage in the vent pipe,base of chimney,dead bird at the furnace where vent connects to furnace or down inside the inducer assy,accessed by removing vent pipe from furnace....if all clear the chimney could be blocked up inside,,is the draft good when vent is removed from base of chimney?..if furnace is a 90%+ type [pvc plastic vent pipe],,then check the intake pipe at the furnace by removing it where it attaches to top of furnace..is the intake clogged with anything?..then check the intake and exhaust pipes outside for blockages,,including ice/frost/snow at the exhaust pipe outlet..

Short cycling, could be because of gas pressure, drain issues from inducer and exchanger (if 90% plus furnace), auxilary limit getting to hot (dirty filters, obstruction, dirty coil), or your flame sensor is failing. Does the furnace lock out? or does it just cycle on and off? If it does how often? Thanks

If the exhaust comes off the top of the furnace, you will need to make sure the condensation will drain all the way back to the condensate outlet found at the base of the inducer blower. If you are having to remove the tube from the pressure switch, there must be a blockage from the inducer down to where ever it drains to. Check to see if all tubes are free of blockages and if there is a condensate trap, clean it out. If the pressure tube you mentioned is facing up toward the blower allowing water to flow into it, reposition it so water will not enter the tube.