Ceiling Extract with Inline Fan (insulate?)

[MortarThePoint]

This is for first floor bathrooms (two) with a loft conversion above. I'm planning to use a Manrose MF100T inline fan, pushing out through roof tile vents which are already installed. In both cases, the ducting will only pass through unheated space and the tile vents are about 1.5m or less from the planned location of the ceiling valve. It feels like insulated ducting is a good way to go to avoid condensation, but I think that's only available as flexible, unless I just wrap rigid ducting with thin (25mm?) mineral wool. I could use partition roll. Or should I just use pre-insulated flexible ducting?

 

Is it worth / required to insulate the ducting?

 

I plan to use fire rated ceiling valves which is a bit silly as a fire in bathroom is not likely, but everything else about the ceiling is fire rated so I don't want to compromise here. Kair seem to do a sensible one (shown below). Going up from 100mm to 125mm massively reduces (-67%)  the flow resistance with a minor (+18%) increase in aesthetic size. I could probably then immediately reduce to 100mm ducting since it is the ceiling valve and tile vents that are likely to be the limiting factors for pressure drop.

https://www.i-sells.co.uk/product/kair-fire-rated-ceiling-extract-valve-white-coated-metal-vent/?attribute_pa_size=125mm

 

[JohnMo]

2 hours ago, MortarThePoint said:

I'm planning to use a Manrose MF100T inline fan, pushing out through roof tile

Not sure I would ever use a fan like that again, for any reason. Not knocking the make or model, just the noise of intermittent fans - Dreadful.

 

Just install a Greenwood CV2 or CV3. Background silent ventilation at a very low rate and automatic (rising humidity) boost, again near silent. 

[Super_Paulie]

2 hours ago, MortarThePoint said:

This is for first floor bathrooms (two) with a loft conversion above. I'm planning to use a Manrose MF100T inline fan, pushing out through roof tile vents which are already installed. In both cases, the ducting will only pass through unheated space and the tile vents are about 1.5m or less from the planned location of the ceiling valve. It feels like insulated ducting is a good way to go to avoid condensation, but I think that's only available as flexible, unless I just wrap rigid ducting with thin (25mm?) mineral wool. I could use partition roll. Or should I just use pre-insulated flexible ducting?

 

Is it worth / required to insulate the ducting?

i did exactly this. Was tricky to get the tubing correct as the vent was "too close" to the motor but with some fancy angles it was pretty straightforward. I insulated by wrapping with 25 or 50mm and then aluminium tape all round to stop it from falling away.
ps, in the first photo i used duct tape which was useless and fell off half an hour later. Use aluminum tape all round is my advice.

 

17 minutes ago, JohnMo said:

Not sure I would ever use a fan like that again, for any reason. Not knocking the make or model, just the noise of intermittent fans - Dreadful.

really? the only noise i hear is the sound of the air getting sucked up, the fan itself is so quiet you cant hear it running from any other room but the loft. Thats why i use the run-on timer as people just kept forgetting to turn it off and it would run all night, non the wiser.

[JohnMo]

2 minutes ago, Super_Paulie said:

really? the only noise i hear is the sound of the air getting sucked up, the fan itself is so quiet you cant hear it running from any other room but the loft.

As I said the fan linked to is silent, no air noise - nothing. I have to take the cover off to see if it's actually running. Plus costs about 50p a year to run at low speed.

[Nickfromwales]

I'm now a huge fan (lol) of the Icon range with the openable shutters for zero draughts during the winter. It is obvs noisier than the inline, but I looked at dampers and gave up, plus I don't want the chatter of a back-draft shutter (these get clogged up soon enough and stop working fully anyhoo....).

[MortarThePoint]

49 minutes ago, JohnMo said:

Not knocking the make or model, just the noise of intermittent fans - Dreadful.

I would prefer a option with real PWM control and Bluetooth so I can add it to home automation, but the only people making those at the moment a NoNames on AliExpress etc.

 

 

16 minutes ago, Nickfromwales said:

I'm now a huge fan (lol) of the Icon range with the openable shutters for zero draughts during the winter

 

These ones:

They do look cool, but if I'm to preserve the ceiling fire rating not an option.

 

32 minutes ago, Super_Paulie said:

photo

 

Looks tidy. Am I right in saying you've used some rubber vibration isolators on the mounting points? Where did you get those?

[Nickfromwales]

22 minutes ago, MortarThePoint said:

They do look cool, but if I'm to preserve the ceiling fire rating not an option

We do solutions here squire, not problems  You can ask your BCO if you can come off the back of that with a piece of rigid soil pipe, and immediately behind the plasterboard you can fit an intumescent pipe collar to comply.

 

https://www.fireprotectiononline.co.uk/intumescent-pipe-closer?attribute_values[1043]=2910&gad_source=1&gclid=CjwKCAjw--K_BhB5EiwAuwYoygI-Y_N7auDjqilxYfotngcAcJ6qpMh0KBFUntWDjy-oGM6V5LZ0thoCTocQAvD_BwE

 

👊

[JohnMo]

37 minutes ago, MortarThePoint said:

would prefer a option with real PWM control and Bluetooth so I can add it to home automation

Why? Not a fan of heating or ventilation that requires third party control especially if internet is involved.

 

Background ventilation that already automatically boosts only when needed - zero to do, zero for home assistant to mess up if an IP address changes blah blah. The ones I mentioned are 0 to 100% speed control.

 

CV2 - Cheaper than the one linked, full speed control for setup (set flow rate for normal and boost), auto boost - no additional wires needed, no AVMs needed, no back draft needed, no additional room grille needed. Fit and forget never hear you fan again.

Edited April 11 by JohnMo

[Nickfromwales]

1 hour ago, MortarThePoint said:

They do look cool, but if I'm to preserve the ceiling fire rating not an option

Also you can use these LINK inside a regular (more attractive) vent. 

[Super_Paulie]

4 hours ago, MortarThePoint said:

Looks tidy. Am I right in saying you've used some rubber vibration isolators on the mounting points? Where did you get those?

 

I did. Used rubber I found at work but it's nothing out of the ordinary, just cut it down to go in each corner. My initial plan was to suspend the whole thing on bungee cords from the rafters but I thought I'd just try it as it was and it was totally fine so I didn't bother.

[MortarThePoint]

15 hours ago, Super_Paulie said:

I did. Used rubber I found at work but it's nothing out of the ordinary, just cut it down to go in each corner. My initial plan was to suspend the whole thing on bungee cords from the rafters but I thought I'd just try it as it was and it was totally fine so I didn't bother.

 

I notice you you don't have a condensation trap. Any issues without it?

[Super_Paulie]

Nope. I did initially design it with a condensation collar I think they are called in the system which just sits in line. Can't recall why I didn't go with it in the end, think I was trying to evacuate the trap to the eaves, but as the run is insulated and so short the 10 minute over-run seems to deal with it. Been in over 2 years now and shows no ill effects, and I enjoy a good long 20 minute shower every evening.

 

I'll likely revisit the whole thing when I pull out the bathroom to  make it all a bit more serviceable, I was in a rush for the install as the builders had made my bathroom "windowless" for a short time with the wraparound extension.