Water in bathroom exhaust vent

[magikal]

Not sure if this really falls under plumbing forums but hopefully someone can help me all the same. Ok, we keep getting water dripping down from the bathroom exhaust vent (fart fan!! ) at the in-laws house. Originally I went into the attic only to discover that the roofers had simply cut back the exhaust tube and strapped to a roof truss rather then fix it right. (It originally had gone to a CanVent) Not wanting to remove the vent and replace, dealing with getting on the roof,etc, I re-routed it horizontally to a vent on the gable. This didn't cure the problem. There is no way water could be back flowing through this. The run from fan to vent is over 12ft long. Yes, it does use metal vent tube. But it seems highly unlikely to me that this much condensation could be accumulating in this.

There is another identical setup for the second bathroom and this hasn't had any issues that I am aware of.

I am stumped at the moment and am open to ideas/advice. Please help!!

 

[specgrade]

I would still wrap some insulation around the duct pipe and see what happens. Mine was doing the same thing and the insulation solved the problem.

 

[majakdragon]

I agree with insulating the exhaust fan duct. Also check the fan blades to make sure no damage has been done by the accumulation of water.

 

[magikal]

Talked w/ a buddy who is a plumber by trade and got the same response. Thanx all....off to wrap some duct work.....

 

[CHRISM]

The previous responders advice to insulate the `Air Duct.Pipe` is correct/good advice - I am based in the U.K. and when we run Horizontal Ventilation Pipework with a `substantial` length we incorporate a TEE fitting which has a 3/4" - overflow pipe size branch connection - which we fit approx. midway between the fan and where the Vent exits the home - this is installed at a SLIGHTLY lower level in the pipe `run`- the pipe sags slightly at the Tee point - the 3/4" branch of the Tee is put at the bottom - with a 3/4" overflow [pvc] pipe run from there to outside the building.
Any Condensation that does condense within the Vent runs to the TEE - and discharges out via the 3/4" `Overflow` pipe. [to a suitable exit/discharge point]
This would `normally` be used where the bathroom has a lot of shower usage - leading to a lot of condensation being drawn into the Vent line - But depending on the `humidity` in your home and the time of year/weather - and amount of people living there - you would be surprised how much condensation does go into the Vent Duct/Pipe.