Condensation on a bathroom extractor fan

[tex431]

Hi got a customer who has a icon 45 bathroom extractor fan, fitted by myself and it develops water droplets on the front grill and drips on the floor. It is flush mounted in the wall through a 40mm polystyrene backed plaster board. I have put some expanding foam between the wall and the back of the plasterboard. Due to the nature of the wall I put a duct through the wall 150mm long, sloping out with a back draft flapper on the wall no water runs in the duct, it only forms on front grill. Any suggestion? Probably going to swop fan to a different brand. Never had this problem with this particular fan before

 

[Geordie Spark]

What does the manufacturers tech support have to say about it??

That would be my first port of call.

 

[tex431]

What does the manufacturers tech support have to say about it??

That would be my first port of call.

I am going to ring them on mon

 

[Jay Sparks]

May be the extraction isn't good enough for the room?? Now don't get me wrong, I don't know exactly how to work it out myself but i am sure there is a formula somewhere??

P.S. Hope I read your post right??? Condom-sation on the fan???

 

[Geordie Spark]

I am going to ring them on mon

For what it's worth, I'm thinking there isn't enough air getting INTO the room for the fan to suck out.

Try running it with the door slightly open & see what happens.

 

[tex431]

Thought you would know being a plumber!

 

[R G]

There needs to be either a vented window , i.e. a trickle vent at the top and open , failing this the door to the bathroom needs to be cut to allow air circulation and for fan to be effective , I would also check that the fan duct and grille are not obstructed....

 

[Geordie Spark]

Thought you would know being a plumber!

I am a man who wears many hats.

 

[tex431]

Funny enough the door has not been fitted yet and I checked the flap opens

 

[tex431]

It's a icon 30 not 45, it was not a cheap one either

 

[Jamzie]

Funny enough the door has not been fitted yet and I checked the flap opens

ok so the flap opens and gets moist, but what about the fan?

 

[Jay Sparks]

There needs to be either a vented window , i.e. a trickle vent at the top and open , failing this the door to the bathroom needs to be cut to allow air circulation and for fan to be effective , I would also check that the fan duct and grille are not obstructed....

Does the fan have overrun?? i.e. it stays on for a timed period, after the light/fan is switched off?

Jay

p.s. Geordie is a plumber....but that dont mean he knows owt!!!lol
Sorry Geordie, only joking....I know you Mackams know loads.lol

 

[tex431]

Yes it does

 

[R G]

What heating have they got in this bathroom. and also is their condensation elsewhere in the house ..

 

[ruston]

Funny enough the door has not been fitted yet and I checked the flap opens

So you are heading for a damp house then using it with no door on. The moisture will be flowing into the bigger air space and probably not be flowing to the fan. It is air flow you need.

 

[tex431]

The bathroom door is going to be fitted, it is a larger than average bathroom with 2.7m height ceilings in an old Victorian house (been modernised)

 

[trev]

.I know you Mackams know loads.lol

Divvent ye Iva call wor Fatha a mackem! Daint myek uz come owa there an clash ya lugs bonny lad!

 

[R G]

I have seen similar issues in timber framed houses with a membrane in the walls , dampness and mould issues especially in cupboards and closed voids , The customer will need some sort of ventilation system in use together with heat recovery combined ..

 

[tex431]

Large Towel rail and ufh, not always on though.

 

[Guest125]

Does it only occur when the shower is on?

 

[tex431]

Yes it does,

 

[ruston]

The bathroom door is going to be fitted, it is a larger than average bathroom with 2.7m height ceilings in an old Victorian house (been modernised)

The door off could well be the problem, with no heat in the room using the bath/shower the condensation will be greater.

 

[tex431]

Good point, I will wait and see

 

[ruston]

Good point, I will wait and see

Work in progress lol.

 

[Leesparkykent]

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this should work if you fit it in the ducting, will stop the cold air traveling through the duct and meeting the warm air and causing the condensation.

 

[Octopus]

Yes it does,

Tell them to turn the fan on. Moisture can't exist if the fan is running. I don't think the user is telling the truth

 

[Guest125]

The door off could well be the problem, with no heat in the room using the bath/shower the condensation will be greater.

Exactly. If the fan surface is cold when the steam hits it it will turn to water.

 

[ruston]

Exactly. If the fan surface is cold when the steam hits it it will turn to water.

That's my view too. An accumulation of circumstances

 

[Guest125]

Try running a 3kw fan heater extended from the landing socket into the shower room to see if it combats the problem.

 

[Guest125]

^^^^^^^joking joking joking. Do not do this - dangerous ^^^^^^^

 

[Jay Sparks]

^^^^^^^joking joking joking. Do not do this - dangerous ^^^^^^^

----.....why not???? I have just set this up while are lass is in the bath!!!lol

 

[Guest125]

----.....why not???? I have just set this up while are lass is in the bath!!!lol

Some on here would have junped all over that as irresponsible blah blah blah and then tomorrow say that everyone on here should know what they are doing blah blah blah.

11pm Electricians forum is sooooo much more relaxed.

 

[Guest125]

11pm is the new 10pm.

 

[Jay Sparks]

11pm is the new 10pm.

11pm is when Jay has had a drink...lol. Only on Fridays and Satudays.lol
I don't mind mind having a laugh with anyone. Even if your'e a plumber...lol. I will only post if I have something instructive to say.....unless someone has misread a post!lol. But after that......most things go!!


Jay

 

[Jay Sparks]

11pm is when Jay has had a drink...lol. Only on Fridays and Satudays.lol
I don't mind mind having a laugh with anyone. Even if your'e a plumber...lol. I will only post if I have something instructive to say.....unless someone has misread a post!lol. But after that......most things go!!


Jay

Sorry....constructive, I meant to say!!

 

[GB.Kayak]

Hi got a customer who has a icon 45 bathroom extractor fan, fitted by myself and it develops water droplets on the front grill and drips on the floor. It is flush mounted in the wall through a 40mm polystyrene backed plaster board. I have put some expanding foam between the wall and the back of the plasterboard. Due to the nature of the wall I put a duct through the wall 150mm long, sloping out with a back draft flapper on the wall no water runs in the duct, it only forms on front grill. Any suggestion? Probably going to swop fan to a different brand. Never had this problem with this particular fan before

Hi Tex, when does it develop this condensation? Before it runs, while it is running or when it switches off? What are the conditions in the bathroom at the time? Condensation levels and bath full of hot water or empty, or shower running hot etc? It is just as much a case of identify the full circumstances like you would if fault finding an electric circuit ... without possession of the full facts you, or other members, may come to the wrong conclusion! That brings with it of course possibly expensive 'stabs in the dark' which do not solve the real problem.


If the condensation forms while the fan is running and the level of humidity at the time is high, it could be a case of 'you cannae change the laws of physics' as Scotty used to say! The lowering of air pressure in the room close to the fan as a result of the fan moving air out of the room and subsequent rise in air pressure at the stagnation points on the grill in front of the fan mean that the dewpoint falls and then rises again leading to the condensation on the grill. The only ways to avoid the condensation are to change the local atmospheric conditions at the grill; either:


- Heat the fan grill to above the dewpoint temperature for the combination of air pressure, temperature and humidity at that point.


- Heat the air so that the temperature of the air at the grill is above its dewpoint for the humidity level at the time; difficult if the surface of the grill is cold leading to cooling of the air and condensation ... refer to the above!


- Reduce the pressure fall and rise by reducing the fan speed and therefore extraction rate!


- Do what the Victorians did ... open the window and ventilate the room after bathing or showering! Closing the door after exiting the room of course to reduce the loss of heated ... and humid air from the rest of the house. Return to close the window when air has changed and condensation evaporated!


I think like many things, in the electrical and wider world, we forget that there are some things that those who went before knew and based their designs and installations upon. Victorian ... indeed the woodwork in any house will decay if exposed to moisture. Victorian houses are designed to be well ventilated! Wrapping our houses in insulation and expecting to live in temperatures of ~ 20 degrees Celsius + will, unless we also prevent the moist air from penetrating to cold surfaces, result in condensation and then rot in timber. It is a fallacy to believe that insulation and vapour barriers can prevent this ... you have been warned! ;-)) Friendly warning but serious none the less!

 

[Octopus]

I think that the OP is ambigious.

We have an Icon 15 in our cloakroom - it never has condensation on it and that's because its cool in there.

To have condensation "dripping" off a fan cover I can only imagine this happening when:

1. The room is cool and the shower is used, the fan is not used, creating condensation on the "cool" surface of the fan

2. The house is hot, the bathroom is poorly heated, the door is left open and the excessive warmth is condencing on the cover of the fan.

3. Inadequate ventilation into the bathroom and the fan is only switched on after the shower has finished.

 

[Geordie Spark]

Hi Tex, when does it develop this condensation? Before it runs, while it is running or when it switches off? What are the conditions in the bathroom at the time? Condensation levels and bath full of hot water or empty, or shower running hot etc? It is just as much a case of identify the full circumstances like you would if fault finding an electric circuit ... without possession of the full facts you, or other members, may come to the wrong conclusion! That brings with it of course possibly expensive 'stabs in the dark' which do not solve the real problem.


If the condensation forms while the fan is running and the level of humidity at the time is high, it could be a case of 'you cannae change the laws of physics' as Scotty used to say! The lowering of air pressure in the room close to the fan as a result of the fan moving air out of the room and subsequent rise in air pressure at the stagnation points on the grill in front of the fan mean that the dewpoint falls and then rises again leading to the condensation on the grill. The only ways to avoid the condensation are to change the local atmospheric conditions at the grill; either:


- Heat the fan grill to above the dewpoint temperature for the combination of air pressure, temperature and humidity at that point.


- Heat the air so that the temperature of the air at the grill is above its dewpoint for the humidity level at the time; difficult if the surface of the grill is cold leading to cooling of the air and condensation ... refer to the above!


- Reduce the pressure fall and rise by reducing the fan speed and therefore extraction rate!


- Do what the Victorians did ... open the window and ventilate the room after bathing or showering! Closing the door after exiting the room of course to reduce the loss of heated ... and humid air from the rest of the house. Return to close the window when air has changed and condensation evaporated!


I think like many things, in the electrical and wider world, we forget that there are some things that those who went before knew and based their designs and installations upon. Victorian ... indeed the woodwork in any house will decay if exposed to moisture. Victorian houses are designed to be well ventilated! Wrapping our houses in insulation and expecting to live in temperatures of ~ 20 degrees Celsius + will, unless we also prevent the moist air from penetrating to cold surfaces, result in condensation and then rot in timber. It is a fallacy to believe that insulation and vapour barriers can prevent this ... you have been warned! ;-)) Friendly warning but serious none the less!

Spot on!!

 

[R G]

Which is why it would be wise to install whole house ventilation with a central unit combined with heat recovery just as they do in North America and what has to be done in timber frame houses , as already mentioned

 

[GB.Kayak]

I think that the OP is ambigious.

We have an Icon 15 in our cloakroom - it never has condensation on it and that's because its cool in there.

To have condensation "dripping" off a fan cover I can only imagine this happening when:

1. The room is cool and the shower is used, the fan is not used, creating condensation on the "cool" surface of the fan

2. The house is hot, the bathroom is poorly heated, the door is left open and the excessive warmth is condencing on the cover of the fan.

3. Inadequate ventilation into the bathroom and the fan is only switched on after the shower has finished.

M ... 'warmth' does not condense, moisture vapour condenses!

Which is why it would be wise to install whole house ventilation with a central unit combined with heat recovery just as they do in North America and what has to be done in timber frame houses , as already mentioned

How long would you trust the vapour barrier to last ... we jump through significant hoops now to reduce the hazard to users of electrical installations because of the risk of metal pointy things piercing our widely spaced and 'sparsely' distributed wiring. Can you honestly assure the integrity of that all enveloping barrier for the 30 and rarely 50 year design life of that timber framed house. If damaged, is it easily repairable ... or repairable at all?


In my lifetime I have lived in recently built new build houses, 50s and 60s properties where the bitumen roofing felt has hung from the rafters and a Victorian, extended in Victorian and again in Edwardian times stone built house ... I don't like the heating bills and we have a long way to go to bring about improvements on the thermal front, but if the minor roof and lime mortar pointing repairs had been done well and kept up, I would not have the current costly repair task on my hands that I have today. Furthermore, if those same repairs are carried out over the next 140 years, there is no reason why she should not last many many more! I don't fancy the chances of any of the other properties that I have inhabited!

 

[Octopus]

M ... 'warmth' does not condense, moisture vapour condenses!

Er no. Just being picky are you??

So are you going to answer the points about what is really going on??

 

[Anthony S]

Hi got a customer who has a icon 45 bathroom extractor fan, fitted by myself and it develops water droplets on the front grill and drips on the floor. It is flush mounted in the wall through a 40mm polystyrene backed plaster board. I have put some expanding foam between the wall and the back of the plasterboard. Due to the nature of the wall I put a duct through the wall 150mm long, sloping out with a back draft flapper on the wall no water runs in the duct, it only forms on front grill. Any suggestion? Probably going to swop fan to a different brand. Never had this problem with this particular fan before

No different to when you see water droplets on window/door trickle vents, its condensation.

 

[GB.Kayak]

Er no. Just being picky are you??

So are you going to answer the points about what is really going on??

Yes ... but pedantic is my middle name! As to what is really going on, I couldn't possibly say as I am not the OP!

 

[Anthony S]

Its about a good balance between: heating, ventilation, insulation

 

[LankyWill]

It's probably due to the coned design of the cover. Why not swap it for a vortice filo 4 or even a vortice quadro micro. The quadro is very powerful and will work on a 4" duct.

 

[Octopus]

Hi got a customer who has a icon 45 bathroom extractor fan, fitted by myself and it develops water droplets on the front grill and drips on the floor. It is flush mounted in the wall through a 40mm polystyrene backed plaster board. I have put some expanding foam between the wall and the back of the plasterboard. Due to the nature of the wall I put a duct through the wall 150mm long, sloping out with a back draft flapper on the wall no water runs in the duct, it only forms on front grill. Any suggestion? Probably going to swop fan to a different brand. Never had this problem with this particular fan before

When? and under what circumstances?

 

[specs]

Funny enough the door has not been fitted yet and I checked the flap opens

you mean there is no door and yet still droplets on grill.

 

[Octopus]

you mean there is no door and yet still droplets on grill.

So hot house, cold air outside is behind grill of fan and the client is surprised that there is condensation??

I do wish the OP would come back and add information!

 

[Darkwood]

I've had this before ... turned out the owner was using the shower for 40mins ...4 " fans are only really designed to cope with a certain amount of moisture in the air to maintain condensation build up... as has already been said - modern living, excessive temperatures and showers that take longer than having a bath.

 

[tex431]

Sorry for the delay, the house is under modernisation. the bathroom door has not been hung yet and the bathroom ufh is operational but not used on the programmer yet or regular. There is a towel rail on the central heating (wet) but only comes on for a short time if at all in the evening. The windows are often opened during the day whilst work is going on. The floor is tiled to ceiling on two sides of the shower cubicle (glass screen on other two sides 2m heigh) and to a metre down one side,the dimension of bathroom are 3.6x2x2.65 heigh. The fan is an icon 30 and will perform @ 32l/sec or 118cubic metres /hr.

The fan comes on with lights and turns off on a timer. It clears the steam no problem so I would say it is adequate

as for the heater could I not just plug it into the socket in the shower cubicle? Lol