Fitting in line fan in attic.

[John Brown]

I'd like to replace the ceiling mounted fan in our bathroom with an inline fan in the attic. The current fan, despite making more noise than a 747 taking off, is ineffectual at best.
There is pipework in the attic, 10mm diameter, with a couple of elbows. I'm not familiar with these fittings, however, are they glued, or push fit?
Also, I don't have any easy access to the external bits of this pipework, and the roof is Cotswold stone, so I imagine that I'd want to find some way to adequately secure the part that sticks out of the roof before cutting through or dismantling anything.

Any advice welcome.

 

[Agent_zed]

looks like soil pipe to me. Something you could do which might make like easier is build a support in wood from the floor in the pic to hold the top vertical part. You should be able to use a soil pipe clip around the indented part to hold it. Then you can remove some of the other bits and plumb in the remote fan. I used aluminium convoluted tube and I also put in a non-return valve so cold air couldn't come back in. The valve has to be mounted horizontally so using the bendy tube may help you be able to make some twists and turns and probably a swirl up and into the vertical part. if that makes sense.

 

[Jake]

I was going to say the same (and it says Osma on the side) - sure it is 100 not 110?

 

[John Brown]

looks like soil pipe to me. Something you could do which might make like easier is build a support in wood from the floor in the pic to hold the top vertical part. You should be able to use a soil pipe clip around the indented part to hold it. Then you can remove some of the other bits and plumb in the remote fan. I used aluminium convoluted tube and I also put in a non-return valve so cold air couldn't come back in. The valve has to be mounted horizontally so using the bendy tube may help you be able to make some twists and turns and probably a swirl up and into the vertical part. if that makes sense.

Ok. Great. So it's push fit with rubber seals? I was planning on using bendy plastic or aluminium ducting, and possibly suspending the fan for quietness.

 

[Jake]

Yes, the first one looks like a push fit bend with a plain end, with the socket side down and the upper plain end going into the socket of another of the same type of bend.

On a second look it says 87.5 (degrees) on the side of the socket, so that has to be a soil pipe bend.

Flexi ventilation ducting will be 100mm or 125mm - the latter will be about the right diameter to clamp onto the outside of a soil pipe socket (not the lip at the end, but the flared bit behind it if you chop the lip with the seal off).

 

[John Brown]

I was going to say the same (and it says Osma on the side) - sure it is 100 not 110?

Ok, could be 110. I thought 100 was pretty standard, so just waved a tape measure at it, rather than using calipers or anything. Presumably 125mm flexible will still clamp to it?

 

[John Brown]

looks like soil pipe to me. Something you could do which might make like easier is build a support in wood from the floor in the pic to hold the top vertical part. You should be able to use a soil pipe clip around the indented part to hold it. Then you can remove some of the other bits and plumb in the remote fan. I used aluminium convoluted tube and I also put in a non-return valve so cold air couldn't come back in. The valve has to be mounted horizontally so using the bendy tube may help you be able to make some twists and turns and probably a swirl up and into the vertical part. if that makes sense.

What fan unit did you use, by the way?

 

[Jake]

Ok, could be 110. I thought 100 was pretty standard, so just waved a tape measure at it, rather than using calipers or anything. Presumably 125mm flexible will still clamp to it?

As I said above 125 flexi should mate quite nicely with the flared bit of pipe at the socket end. I found this out installing soil pipe for my extraction system - cutting the lip off a socket end of a soil pipe fitting or chopping a soil pipe coupler in half gives something that mates pretty well to 125mm plastic blast gates. 125 flexi will be too big to mate well with the pipe itself, and 100mm is too small obviously.

 

[MikeJhn]

Is a condensate trap necessary? Probably not it the fan overrun is sufficient, I would recommend a humidistat in the shower room close to the shower head, not inside the shower zone, but close enough to detect steam.

Used one of these on my own shower enclosure: https://www.tlc-direct.co.uk/Main_Index/Ventilation_Index/Soler_TD_Silent/index.html sufficiently powerful that once you have finished wiping down the shower door you are almost dry.

 

[Jake]

I have an older (not "Silent") S&P in a shower room (also from TLC https://www.tlc-direct.co.uk/Products/SLTD160.html) - it's been running just fine for nearly 20 years. That newer silent one looks good. How honest is the silence? Most of the noise with mine is air noise, can't really hear the fan itself behind that but I guess it is hard to tell without a side by side comparison.

 

[Stuart Moffat]

I have 4 vent axia silent fans (about a year old now). They come with two speed options. If set at the higher speed, they are not silent. Not bad but not silent! If set at the slower speed they are really quite close to silent but shifting less air. But if you get the option that turns on and off depending on relative humidity in the room then they will do a perfectly good job of turning on and off appropriately (you can adjust the sensitivity). It’s way better than having a fast fan speed on a set timer overrun. If you have wet towels, then with a standard timer, these won’t dry on a heated rail in 15 minutes, but the auto setting works well for us. For the likes of a downstairs loo with no shower etc, the relative humidity function is not appropriate, but a silent one on the quiet setting with a long timer setting works well

 

[Fitzroy]

Ok. Great. So it's push fit with rubber seals? I was planning on using bendy plastic or aluminium ducting, and possibly suspending the fan for quietness.

I installed an inline fan in one of my rooms and I ended up installing it on a wooden board separated from the joists by acoustic foam I had lying around. This was a retro fit as initially the board just sat on the joists and there was noticeable noise from the ceiling acting as a sound board.

 

[Phil Pascoe]

I haver a 6" Manrose (48w, iirc) shifting heat through insulated ducts - it's audible, but not to the point of being irritating.

 

[MikeJhn]

I have an older (not "Silent") S&P in a shower room (also from TLC https://www.tlc-direct.co.uk/Products/SLTD160.html) - it's been running just fine for nearly 20 years. That newer silent one looks good. How honest is the silence? Most of the noise with mine is air noise, can't really hear the fan itself behind that but I guess it is hard to tell without a side by side comparison.

The S&P Silent replaced a non acoustic version and it is very noticeable less noisy, you can't hear it when under the shower spray.

 

[HappyHacker]

I fitted an inline quiet fan in a customers bathroom It needed quite a powerful one as there was a long run of duct on the outlet. It was a little noisy in the bathroom not because of the fan but the airflow through the ceiling vent.

Another customer had soil pipe ducting in the attic exiting via the roof and got a lot of condensation running back down the pipe, not helped by the installer effectively making a U bend in the ducting which filled with condensation! I fitted a more powerful silent fan and got rid of the U bend and they had no more problems with condensation from the pipe.