bathroom fan extraction rate

[uk1simon]

Hello,


I want to buy an extractor fan for my mathroom. My bathroom dimensions:
lenght 8ft (2.44m)
width: 4ft 9in (1.45m)
height: 7ft 7in (2.32m)
which means that my bathroom's volume is 290 ft3 (8.21m3).


According to tlc-direct.co.uk required performance for this bathroom size (bathroom with shower) is 148 m3/h.
I'd like to buy an inline fan and use about 6 mtrs of ducting to take the air out through fascia.
And a few questions:
1. is an inline fan with air extraction rate of 220m3/hour too much?
tlc website suggests 148m3/hour
2. can the moist air taken from the bathroom be sucked back in the loft through fascia and cause damage?
3. I don't know whether a powerful inline fan would interfere with the boiler that is located in


the room next to the bathroom.
4. I want to mount the fan on the ceiling in zone 2.
Would I get better result if I fitted the fan in zone 1 on the ceiling above the bathtube?




Regards,
Simon




Regards,
Simon

 

[telectrix]

220 cu.m/hour is fine. the 148 nis a minimum.

mounting...... an in line fan is mounted in the attic. duct from ceiling intake to fan, then from fan to fascia outlet. should not cause damp in attic if the ducting is properly fixed.

mount the inlet grille wherever the steam is thickest.

 

[Geordie Spark]

Hello,


I want to buy an extractor fan for my mathroom. My bathroom dimensions:
lenght 8ft (2.44m)
width: 4ft 9in (1.45m)
height: 7ft 7in (2.32m)
which means that my bathroom's volume is 290 ft3 (8.21m3).


According to tlc-direct.co.uk required performance for this bathroom size (bathroom with shower) is 148 m3/h.
I'd like to buy an inline fan and use about 6 mtrs of ducting to take the air out through fascia.
And a few questions:
1. is an inline fan with air extraction rate of 220m3/hour too much?
tlc website suggests 148m3/hour
2. can the moist air taken from the bathroom be sucked back in the loft through fascia and cause damage?
3. I don't know whether a powerful inline fan would interfere with the boiler that is located in


the room next to the bathroom.
4. I want to mount the fan on the ceiling in zone 2.
Would I get better result if I fitted the fan in zone 1 on the ceiling above the bathtube?




Regards,
Simon




Regards,
Simon

Is the boiler a room-sealed appliance?

 

[rob28870]

The fan speed required to extract at 220m3/hour may be a bit noisier than you would like (depending on the type of duct you use and location of the fan).

These are 184m3/hour on high speed with a lower speed setting if you need it Airflow Aventa Timer Fan 100mm Mixed Flow 2 Speed [9041086]

Moist air won't come back in as long as you're not dumping directly over the top of the open window (even then its highly unlikely).

Best check the boiler implications first on a plumbing and heating forum though.

 

[Octopus]

The thing to remember is that for the "extraction" to work properly, the room must be able to "suck" air into it - so be prepared to shorten the door as part of the project!

 

[morph]

as long as boiler is not open flued it will be fine and even if it is open flu and gas or oil as its in the next room that too should be fine, the only real time to worry is with open flu solid fuel appliances

 

[nickblake]

Screwfix do a manrose inline duct kit fan outlets inlets ducts etc good little fans to one point i will make is the fan will have to be fused down and this type of work is notifiable too ... im sure thats 2 points ...

 

[morph]

Screwfix do a manrose inline duct kit fan outlets inlets ducts etc good little fans to one point i will make is the fan will have to be fused down and this type of work is notifiable too ... im sure thats 2 points ...

not wanting to hijack post in anyway, but how do you fuse yours down when its a timer fan, i know someone who puts line to line and switch line to neutral then connector block for the neutral . i have pointed out to him that this means the switch line is not fused
.
personaly i put fused connection unit before the light so the light and fan are both fused down as this seems to be the simpliest method

 

[Geordie Spark]

not wanting to hijack post in anyway, but how do you fuse yours down when its a timer fan, i know someone who puts line to line and switch line to neutral then connector block for the neutral . i have pointed out to him that this means the switch line is not fused
.
personaly i put fused connection unit before the light so the light and fan are both fused down as this seems to be the simpliest method

It's nice to know that I did something right !!

 

[nickblake]

i use one of these and fuse the perm live side as per manufacturers instruction you will find that the fan itself will not be energised if the perm live is not presant as its this that enables the timer circuit to operate but with out it it wont work and the issue is the fans seizing and over heating causing a fire i have seen this happen on several occasions one causing £1000,s work of damage the other where the fan motor had caught fire dropped out of the housing and burnt a hole into a soil pipe where the fire was extinguished , these are available from scholmore click

 

[morph]

thanks
is that a two pole switch with the line being isolated by fuse removal?
its a good looking unit i was wondering why no one had made one lol
is the purpose of the manufacturer requiring it to be fused down due to the potential overheating? do they draw excess current when at fault then ?

thanks

 

[Geordie Spark]

i use one of these and fuse the perm live side as per manufacturers instruction you will find that the fan itself will not be energised if the perm live is not presant as its this that enables the timer circuit to operate but with out it it wont work and the issue is the fans seizing and over heating causing a fire i have seen this happen on several occasions one causing £1000,s work of damage the other where the fan motor had caught fire dropped out of the housing and burnt a hole into a soil pipe where the fire was extinguished , these are available from scholmore click View attachment 14520

That looks nice .. it saves having the twin backbox with both the FCU & Fan Isolator in it.

 

[nickblake]

they are great i use them all the time , they are modualr face plase fuse holder and a fan isolator its a 3 pole switch so the perm live goes into the switch then the out put goes to the fuse then to the fan all you have to add is the link from the switch to the fuse doing it this way when you switch the isolator off the fuse is dead so you can remove the fuse with out it being powered as you should

 

[nickblake]

thanks
is that a two pole switch with the line being isolated by fuse removal?
its a good looking unit i was wondering why no one had made one lol
is the purpose of the manufacturer requiring it to be fused down due to the potential overheating? do they draw excess current when at fault then ?

thanks

its all about maintainance if you have a fan thats not been cleaned and looked after you get a build up of dust and what ever else im sure youve see this if it buids up to the extent that the fan siezes then the fan can over heat and in some cases catch fire , this can also happen if the bearing siezes for the impellers are damaged etc , the problem is the coil when it siezes draws less current than the 6 amp lighting circuit requires to trip so catches fire hence the reason for fusing them down

 

[MarkieSparkie]

The extractor fan should be mounted as high on the wall as practical and preferably less than 400mm below the ceiling.
Bathroom:
Intermittent Extraction:- 15 litres/second
Continuous Extraction:- 8 litres/second
Building Regulations, Approved Document F1:2010 Tables 5.1a & 5.2a