Extractor fan problem

[Bodidly]

Morning all

My extractor fan in the bathroom has just burnt out for the second time. I have nobody to blame but myself as the exit pipe goes slightly up as it goes through the outside wall causing all condensate to run back into the guts of the fan. I have removed the fan and got soaked in the process but what shall I do next?

Option 1. Block up ducting inside and out and just open the window when showering.

Option 2. Remove current exit pipe and correct the problem with the angle. This sounds easy but access is difficult and the pipe is mortared into a 2' thick granite wall which I can only really get at from the outside.

The soggy fan


The pipe is going out through the end wall you can see here.


I should ad that most of the time we only use the window for moisture removal and I have only been using the fan in the recent cold spell.
There is probably an option 3,4,5 but I don,t know what they are.

All ideas welcomed
Beau

[johnrae]

Because you don't use the fan for every shower its windings get wet due to room humidity and corrode.  The solution is to use the fan at ALL showers and either fit it with a timer to run-on after the shower or leave it running for say 10 minutes after you've finished.  Once the room humidity is back to normal there should be no condensate run-back.

[Heinz]

Are you sure it's burnt out? My utterly, utterly useless Expelair bathroom fan melted the thermal fuse which was taped to the windings. Bought a few replacements for next to nothing and soldered in a new one. Having said that no electric motor should be wet like yours, recipe for disaster... 

H

[pb]

Other possible things to try:

- Fit a condensate trap in the outlet duct

- Replace the fan with an in-line type mounted horizontally, so that any condensate runs to the bottom of the duct rather than going through the motor on its way down

[JohnS]

Are you sure that rain, especially horizontal rain, cannot get in to the tube from the outside?

If it can, you will need to change the angle of the pipe.

[clivejo]

Because you don't use the fan for every shower its windings get wet due to room humidity and corrode.  The solution is to use the fan at ALL showers and either fit it with a timer to run-on after the shower or leave it running for say 10 minutes after you've finished.  Once the room humidity is back to normal there should be no condensate run-back.

I agree with this option, you need to run the fan more often.  That condensation looks fresh (i.e. the motor was cold and steam rising from a shower has settled there)  Any time you are raising the moisture level in the room you should use the fan.  Even while having hot shave in the morning, when the bathroom is cool, will fog up my mirrors!

[Bodidly]

Heinz
I am pretty sure one of the windings has gone because it does try to turn but fails while moaning a bit.
pb
Fitting a condensation trap would require me to pull the plasterboard off to get access to the duct also presumably the trap has to have a drain which would require hacking up the wall as well. I know this would be good solution but if I can avoid all that work I will.
JohnS
I don't think rain has caused the problem as the last time the fan failed I fitted a cowl and a one way flap because I thought rain had been the problem. Also it exits on a north wall so not much driving rain from that direction.
johnrae
At the moment your solution sounds the most appealing as I have fan in our utility room that never gets used and it has a timer and a humidity control. I will use the dead one to blank off the hole.

Thanks all for your ideas

I think I will go with johnrae's idea unless you can see some problem with this.

Beau

[clivejo]

Turn the power to the fan off and blast a bit of WD40 or other spray oil in around the axle.  Turn with your finger (or screwdriver if you got bunty fingers) to work the oil into the bearings.  Then try it with the power on.

[acresswell]

How about swapping the fan for one with a smaller diameter?  You could then just stick the new duct through the old one, angling it down slightly at the same time and filling the gap around the outside with expanding foam...  could probably leave the old vent on the outside and just work from the inside.

I'd suggest you don't rely on a dead fan to provide anything like a decent seal.  However, you could stuff the duct with old carrier bags (or other plastic inside a carrier bag) and then stick an old fan on the inside to make it look prettier.  This does have the advantage that it's easily reversible so you could try managing without the fan fora few months and see if you really need it.

[rogeriko]

Run the wire through the duct and put the fan outside, maybe a little squirrel cage fan with a weatherproof motor.

[johnrae]

Question :-
When you did use the fan, did it actually remove "steam" from the room. 

From your second photograph it appears that the flexible exit ducting is obstructing the air discharge of the fan.  These cheap (or not so cheap) axial fans are notoriously useless when discharging into any duct that creates obstruction.  They are really only suitable for a direct straight connection to the outside.  For systems with long or convoluted ducting you really need a centrifugal style fan.

Since you seem to be getting "brainstorm" suggestions, how about simply fitting a fan in the bathroom wall, from the interior of the house and "pressurise the bathroom.  This will then force the steam out through windows or the existing fan ducting.

[Bodidly]

Hi johnrae
I never thought the fan was very effective but it did the job if left on for 45mins or so. The tube is not blocked but it does go through a 90 degree turn in a 15cm radius and then straight for a meter to get out through the wall. I have tried to raid the fan from the utility room but I must have glued it into the ducting so a new fan of some sort is now necessary. You have got me thinking with your idea of pressurising the room. The utility room below tends to be quite warm and the bathroom errs on the cold side so a fan in the floor might work if I can get past all the UFH pipes.

I know I did a bad job with the fans in our house. I used to live in a draughty old farmhouse and the need for decent ventilation never seemed important so I just did enough to comply with building regs.

Beau

[clockmanFR]

In wet rooms and shower rooms i fit 24v DC types with a separate transformer. On many occasions due to moisture the fan just hums, switch it off, switch it on, it gets going eventually. I have also noticed that some times the back pressure wants to turn the fan the wrong way.

Just my observations.