Bungalow bathroom fan, no external walls

[timhoward]

I've just had a look at an extractor fan not working. As per title it's a bungalow and there are no external walls, so it vents through the loft and roof.
Earlier this year the customer requested a more powerful fan and the sparks fitted a Manrose inline unit. Fair play.

But the thing is, there's a vertical ducting run from the Manrose unit to the roof vent, and when I got there I emptied half a bucket of water from the vertical ducting and the fan.
I happened to see the neighbour who obligingly let me look at their setup, which was the original ceiling mounted fan and some heavily cladded ducting going straight up. I guess any condensation would simply fall down and through in that scenario.

Options as I see it are:
a) change it back to a ceiling fan and try and find some insulated ducting and reinstate a directly vertical run. Customer not keen as the fan location isn't above the bath and they wanted a better solution.
b) fit another Manrose unit, insulated ducting and presumably some kind of condensation trap.
c) Change to a very long horizontal pipe run through the bungalow side wall, this would be at least 6-7m of pipe.

I'm thinking a) as it's apparently worked for years before, but glad to hear any thoughts or previous experiences.

 

[Pretty Mouth]

Sorry bad example link, but as you said 100mm are available. Just need to pipe the condensation to somewhere.

Nothing wrong with the one you linked to, so long as you've got the right pipe to go with it

 

[Zerax]

I had exactly the same setup to sort out a few months back... customer reported the fan dripping, then not working. The bathroom had no external ventilation or windows. I went for a 'belt and braces' approach... fitted a more powerful in-line fan, with insulated ducting and a condensation trap that ran out to the gutter. Also added 2 x Louvre vents in the door so that the fan could always draw air from somewhere. No callback since.

 

[timhoward]

I had exactly the same setup to sort out a few months back... customer reported the fan dripping, then not working. The bathroom had no external ventilation or windows. I went for a 'belt and braces' approach... fitted a more powerful in-line fan, with insulated ducting and a condensation trap that ran out to the gutter. Also added 2 x Louvre vents in the door so that the fan could always draw air from somewhere. No callback since.

Thanks, that's very helpful to know. I certainly don't want to be the 2nd one who messed it up....

So taking the general principles from the answers I'm intending to get the fan much nearer the roof with a condensation trap and a very short length of insulated ducting to connect to the roof vent. I'm hoping to use entirely rigid ducting from the ceiling to the fan.

 

[brianmoooore]

If you use solid ducting, you can use these;

Condensation Trap for 4 Inch Soil Pipe | Manrose (1440 / MONV434)

Or has somebody mentioned that..

These work well, but you still need a 22mm pipe sloping downhill to somewhere it can drip.

 

[Midwest]

These work well, but you still need a 22mm pipe sloping downhill to somewhere it can drip.

Which is what I said in #14

 

[Zerax]

These work well, but you still need a 22mm pipe sloping downhill to somewhere it can drip.

But it's just overflow pipe... so very easy to work... if it can't be led out to a gutter, then it'll need to go via a fanny trap to the waste somewhere.

 

[Mike Johnson]

Or connected back to the shower extract point and drip into the shower tray and hence the tray waste?

 

[Zerax]

Or connected back to the shower extract point and drip into the shower tray and hence the tray waste?

Is that the French way ??

 

[timhoward]

Or connected back to the shower extract point and drip into the shower tray and hence the tray waste?

Funnily enough the first place I looked to drill out for the drain would have been over a neighbours hot tub....!
It's going to go into a gutter.
I'm all for creative ideas but recycling sweaty steam back into the very place it came from isn't quite ticking the box for me.

 

[Mike Johnson]

It's the only way to do it if you don't have access to a gutter or soil pipe, bonnet hipped roofs and soil pipe on the other side of the roofs.

 

[Mike Johnson]

I'm all for creative ideas but recycling sweaty steam back into the very place it came from isn't quite ticking the box for me.

Surely from the condensate trap it's only condensate water, no steam involved.

 

[Pretty Mouth]

Or connected back to the shower extract point and drip into the shower tray and hence the tray waste?

Not sure I understand what you're getting at Mike.

In my experience, the trap is usually fitted just above the ceiling grille, to catch all the condensation from the ducting above, and drain it somewhere where it won't be a problem (eg. to outside the property).

Your suggestion is to drain the condensation back through the ceiling grille? What would be the point of the condensation trap?

 

[brianmoooore]

The 150m2 of slate roof that I spent the first 'lockdown' replacing, had suffered multiple leaks for years, with at least a dozen bowls placed around inside the loft to catch the drips. After it had rained, there was varying quantities of water in these bowls, but after a week or so without rain, most of them would be bone dry.
I suspect that if something with a reasonable surface area, such as a washing up bowl, was placed in a reasonably well ventilated loft, so as to catch the drips from a condensate trap, its contents would evaporate faster than it filled.

 

[freddo]

I suspect that if something with a reasonable surface area, such as a washing up bowl, was placed in a reasonably well ventilated loft, so as to catch the drips from a condensate trap, its contents would evaporate faster than it filled.

And if not, you could run an overflow pipe from the washing up bowl to the gutter or similar.