extractor fan issues (as in, it doesn't work very well)

[MyWifeNowDave]

Hello all, I'm new to the forum and I was hoping to get a bit of advice please

I'm a plumber and I've put a new fan in my bathroom. The old one was ineffective and didn't clear the steam very well. What I'd like to achieve is to be able to run a shower without the walls and mirror steaming up.

The new fan is a vent axia acm100t, the fan speed is at the highest setting and the timer overrun is running around 20 minutes after light goes off. I have situated the fan in the loft about 700mm from extraction grill (bathroom end), which is above the shower area. The ducting is insulated ducting and goes down to a soffit vent. All other soffit/roof vents within 1m of extractor vent have been blocked up to stop moisture getting back up into the roof space. I have about a 13mm gap on the bottom of the door to allow a flow of air into the bathroom..... but the walls and mirror still get steamed up, although the room doesn't fill up with steam the way it used to do. The bathroom is only about 1800mm x 1800mm.

I have just had a shower and the walls are still pretty wet . The heating isn't on at the moment as the stat downstairs is on 20 degrees.....

Any ideas would be gratefully received as I don't know what else I can do to improve the situation.

 

[buzzlightyear]

I'm a plumber and I've put a new fan in my bathroom. The old one was ineffective and didn't clear the steam very well. What I'd like to achieve is to be able to run a shower without the walls and mirror steaming up.

have you no windows in the bathroom!

 

[mhar]

If you are requiring instantaneous removal of the steam / moisture, it would require quite a draught through your bathroom.

Wire in a humidistat so that the fan does not turn off until the moisture levels in the air are at an acceptable level

 

[Octopus]

1. Hold a piece of toilet paper in front of the ceiling grill - if it stays there, the fan is working.

2. Don't be surprised about the moisture on the walls - that's what happens when you introduce warm moist air into a room

3. Sounds like its better than before.

4. Unless you have a bigger, or "stronger" fan nothing is likely to change.

5. Consider adding a heat mat behind the mirror...

 

[Phil Thompson]

Or get an inline mixed flow fan with a higher cfm air movement.

 

[telectrix]

turn the heating up, cut your shower time down to just as long as it takes to scrub up.

 

[Octopus]

turn the heating up, cut your shower time down to just as long as it takes to scrub up.

lower the temperature of the shower water!

 

[buzzlightyear]

or put in a 12in fan .

 

[MyWifeNowDave]

Thanks guys for the responses.

So am I being unreasonable to expect no steaming up at all? I thought 220 m3/he would prevent that..... providing I get the airflow? Even tried showering with door slightly ajar to see if that improved things .....and if so put in a low level vent....but it didn't.

Would changing to a acm150t sort this out (460m3/hr) as every so many months I need to fight back the start of mould..... it's not bad and is easily gotten rid of... but it's bloody annoying though

 

[MyWifeNowDave]

What's a mixed flow fan????

 

[buzzlightyear]

nice picture by the way .where you once with black &white minstrel boys!

 

[buzzlightyear]

What's a mixed flow fan

 

[Taylortwocities]

If you are trying to suck air out of the room down a 100mm dia pipe then you must have a air inlet to the room of at least an equivalent size.
otherwise your fan will just be tryin to create a vacuum in the room.

Ideally, air inlet to the room and the point where the air is extracted from the room should be on opposite sides of where the steam is created.

 

[Squid]

How many external walls do you have and did you fit a demister pad to the mirror?

 

[Rpa07]

Are you sure that the whole run of ducting isn't pooled with condensate? If you are then as the others say!
Sometimes it seems like a fan is pulling the air but it's just trying to push it a against a big puddle of water effectively doing nought.

 

[Rpa07]

nice picture by the way .where you once with black &white minstrel boys!View attachment 38209

Quite normal for a Sunday night that - enjoyable as well! I'll bet there was a do-gooder responsible for its demise. That'll be another thread!

 

[davesparks]

when steam meets a cold surface it condenses into water, no matter how much extraction you have.

 

[MyWifeNowDave]

Are you sure that the whole run of ducting isn't pooled with condensate? If you are then as the others say!
Sometimes it seems like a fan is pulling the air but it's just trying to push it a against a big puddle of water effectively doing nought.

It's all brand new as the old fan was ineffective, the ducting is all new and runs from the fan downwards to the grills. Maybe I need a more powerful fan..... or to lower my expectations?

 

[MyWifeNowDave]

Are you sure that the whole run of ducting isn't pooled with condensate? If you are then as the others say!
Sometimes it seems like a fan is pulling the air but it's just trying to push it a against a big puddle of water effectively doing nought.

It's all brand new as the old fan was ineffective, the ducting is all new and runs from the fan downwards to the grills. Maybe I need a more powerful fan..... or to lower my expectations?

 

[Midwest]

I can take long hot showers in my ensuite, using an in-line 100mm extractor fan, with no steaming up

Is your ducting fairly straight, with no bends & under 3m total length. Venting out through soffit always causes poor extraction IMO