If this is the case it could be an incorrectly sized flue pipe which is making water to drain back into the furnace.
Gas furnace flue pipe leaking water from storm.
While this may look like water leaking from your furnace it s actually furnace gases that have turned into their liquid form.
The water drips on a piece of wood in the attic which apparently has always dried before causing an issue.
Improperly installed vent connector that reduces exhaust velocity.
This includes the drain pan and the drain piping.
If this is the case it s best to call your local furnace repair team.
If you have a condensation leak with a standard efficiency then its exhaust or flue pipe may be incorrectly sized.
Improper flue exhaust can result in your furnace leaking water.
In a gas heated home a flue pipe vents the gases out through the roof.
A number of points may fail in the flue but they are mostly easy to detect and fix.
This can cause premature flue failure.
Some causes of exhaust pipe restrictions are the flue cap is missing.
Gas furnace flue pipe leaking water from storm where my gas furnace flue pipe type b runs through my attic i had water dripping from the connections seams in the area where it makes a 45 degree bend water was inside the pipe from blown rain.
Much of the drain system and some of the parts are made of plastic.
There s a chance this has.
It was very windy out during the storm.
This will cause your gas furnace to leak water.
You ll need a furnace technician to diagnose which of these is the issue and then fix it.
It sounds like the flue gas is condensing before it has left the flue.
If your flue pipe is improperly sized or was installed incorrectly the gases move too slowly allowing them to cool down condense inside the flue and drip back toward the furnace.
Other causes of leaking water around a furnace if you have a conventional standard efficiency furnace then its flue pipe may be incorrectly sized.
If you have a standard efficiency furnace usually 15 plus years old it should not be leaking water.
Your humidifier should be getting annual maintenance from a professional to prevent this.
Broken condensation line condensate pump.
Like all installations that poke through the roof sometimes a flue pipe develops leaks that result in water leakage into the attic or roof space when it rains.
A standard efficiency furnace extracts some heat from the combustion gases and quickly vents them out the exhaust or flue pipe.
If you have a whole house humidifier connected to the furnace there may be an issue which is causing the humidifier to leak into your furnace.
There are other reasons why your condensing gas furnace can leak water.
There should be no water involved with a standard efficiency furnace.
B vent leaking from seam in pipe.