Condensation inside bathroom vent fan - update

This is a long time coming. Back in March 2006 I opened a topic stating that I was getting pools of condensation in my bathroom vent fan. The fan in question was a Panasonic FV 11VQL3 110 CFM. I tried insulation aroung the vent pipe - didn't work. Insulation around fan - didn't work; removed the dampener (flappy thing that does not allow air to travel back in fan) - didn't work. Finally I took the fan in the Warranty Shop and they said the Squirrel Cage and motor had to be replaced. I had high hopes. 3 MONTHS later (due to back order of parts) I got the fan back installed it and.... same problem.
I called REWilliams.com and they are going to take the fan back. They were pretty understanding and have a good policy on defective products.
So overall I wanted to say thanks to the people that responded to the original posting "Condensation inside bathrrom vent fan" and say I am getting a new fan from Home Depot. Hopefully this one will work. Heck I might find out that my home has some sort of moisture/venting issue. Funny thing about this whole experience is that I learned more about ventalation and fans that I would really care to know.
Also as far as the Panasonic fan, I hear good things about it. Just cause this one fan did not work for me I am not writing them off. If there was a place that sold them for 100 bucks like REWilliams.com I would try another one but all these fan places sell them for $175.
Regards,
Mike
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I'm curious, does your vent go through the roof or out the wall. I ask because I installed a nice older one in our master bath from a demolition salvage place that removes fixtures from high-end houses, and I was careful to slope the vent tube down to the wall exit. I've had no problems
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Hi Eric,
Actually I did a horizontal run of 1.5 feet with a slight slope down and then it curved up to a vent in the roof. The install instructions showed that install or a wall exhaust install.
Just to give you a little more information. I actually removed the dampener and the vent pipe and did a test of running a hot shower and the fan venting into the attic space. After 8 minutes there was a good size pool of condensation inside the fan. Got this idea from a few contractors at church. This test showed that the steam from the bathroom was not exiting the fan fast enough.
I already have the new fan and plan to install this weekend. I'll let you know what happens.
Eric in North TX wrote:

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I have learned the hard way to avoid metal tubing, it is cold in winter and can produce a considerable amount of condensation. Now I only use 4" PVC sewer pipe, it is not as thick walled as drain and vent pipe and has belled ends for easy connecting. Since I changed I have not had any condensation problems. Also in my climate and because it runs through the attic I make sure that it is buried in the insulation for extra insurance, but so was the metal pipe that gave me problems.

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Put a automatic timer on it so it runs 10 minutes after the shower is done.

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i alway move up one size and never had an issue

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Thanks but I tried everything and I still get a pool of condensation in the fan. The fan is 110cfm and I only need 80cfm for the size of my bathroom. Trust me I have been through it all except tearing a huge hole in my ceiling and roof to allow the steam to vent. ;) Well except for the PVC idea but the problem is not with the tubing.
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Are you sure it is not the tubing, I had water running backwards through the tubing and dripping out the fan when the fan was turned off. I had so much water because my tubing ran horizontally through the attic and then turned up through the roof. This gave about 18" of tubing that I could not get adequate insulation around. Using the PVC tubing I built a simulated "trap" at the bottom of the vertical section (and even ran a 1/4" diameter tube from the trap area to allow me to vacuum the water out of the trap in case it built up enough to block the airflow, as it did once on one run) to catch the water and prevent it running back to the fan. I did a lot of crawling around my attic to correct this problem, even tried an in-line fan near the end of the run in one bathroom to see if it would help (no difference). My solution that worked was PVC tubing, piling the insulation over the pipe, and building traps at the bottom of the short vertical run to catch any liquid.

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Yep, I am absolutely sure it is not the tubing. I actually removed the tubing and ran the shower and fan for 8 minutes and condensation built up in the fan. The fan was venting into the attic for this test.
Also I replaced the fan this weekend with a new one from Home Depot. It's 110cfm and I am using the exact same materials (tubing and vent) and I have no condensation in the fan.
I am very excited to have this project done and a working fan.
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