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Hi guys, I have posted this on the plumbers site and I know some of our sparks do know about boilers, also as its a grey area for me and wanted advice if i am correct or not.

Situation is I am doing a bathroom simple stuff, new light fan and shower, However I have noticed the bathroom has a linen cupboard which houses a multipoint boiler. Not a major problem electrically but it occured to me that this boiler which is not a sealed type (sorry did not get the make/model) is old and relies on a air vent next to it to outside and has air vents top and bottom of the cupboard door for its safe operation, that bit I understand.
Now I would be installing an extract fan in this room which will no doubt have the door shut making a negative air preasure in the room and air wanting to take the easiest route will come from the boiler cupboard. My thoughts are that fumes could be sucked into the room from the boiler am I correct ?
At the moment I have said i don't think its possible due to the type of boiler fitted in its location but i did not want egg on my face being wrong and also i do like to sleep at night. I'm sure this is correct but wanted to be 100% before i went back hopefully armed with the facts.

I hope I have explained the setup correct but it just was ringing wrong in my head when i see the boiler in there.
Many thanks in advance for your replies.
Needasparks
 

telectrix

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can you fit the fan so as to extract into the boiler cupboard, then outside?
 
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  • #3
see where your going tel, simple answer is no, not really.
It was going to be a humidistat job as council grant job and in the spec, however i think it must have been an oversight.
Glad i spotted the issue as I have come across similar before but not quite the same setup.
 

ruston

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You are right to be concerned about spillage from the boiler depending on the power of the fan. I know gas fitters that have issued danger notices for ceiling fans in living rooms with open flue boilers. Best to get professional advice on this I think.
 

topquark

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Can you replace the extractor fan with a heat exchanger (vented back into the room)? Expensive option though.

Only other choice I can think of is to run an additional fan venting into the bathroom (would have to be both timed though).
 
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  • #6
Yeah I don't think i have an option other than just refuse the fan install really and throw the prob back to the surveyor for not spotting it.
It makes it no worse than it is now. I would think left alone its fine as is but changes to airflow in the room is where i fall down, not knowing enough about the boiler regs etc.
cheers all for your input though guys.
 

telectrix

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best way to avoid a boiler conflict is to make sure you keep your mother and her mother well apart.
 
Hi guys, I have posted this on the plumbers site and I know some of our sparks do know about boilers, also as its a grey area for me and wanted advice if i am correct or not.

Situation is I am doing a bathroom simple stuff, new light fan and shower, However I have noticed the bathroom has a linen cupboard which houses a multipoint boiler. Not a major problem electrically but it occured to me that this boiler which is not a sealed type (sorry did not get the make/model) is old and relies on a air vent next to it to outside and has air vents top and bottom of the cupboard door for its safe operation, that bit I understand.
Now I would be installing an extract fan in this room which will no doubt have the door shut making a negative air preasure in the room and air wanting to take the easiest route will come from the boiler cupboard. My thoughts are that fumes could be sucked into the room from the boiler am I correct ?
At the moment I have said i don't think its possible due to the type of boiler fitted in its location but i did not want egg on my face being wrong and also i do like to sleep at night. I'm sure this is correct but wanted to be 100% before i went back hopefully armed with the facts.

I hope I have explained the setup correct but it just was ringing wrong in my head when i see the boiler in there.
Many thanks in advance for your replies.
Needasparks

"Hello needasparks",

You are absolutely correct to be VERY concerned about this situation.

From your description about the Boiler / Multipoint Water Heater [?] NOT being a Room Sealed Appliance and the Air Vents for the Cupboard that the Boiler is located in there could already be a Very Dangerous situation:

If the Boiler / Multipoint Water Heater [?] is an Open Flued Appliance which relies on Air Vents for `Combustion Air` the Compartment / Cupboard should ONLY have Air Vents direct to outside Air - There should be NO Air Vents in the Cupboard Door - into the Bathroom !

Also - IF the Appliance is an `Old` Open Flued Multipoint Water Heater - fitted in the Bathroom before this type of Appliance was BANNED from being in a Bathroom / Shower Room - Locating it in a Bathroom Cupboard would NOT have been the `Answer` [in the past] for getting over those Regulations.


If as You pointed out there was ever ANYTHING that caused the Appliance Ventilation or Flueing to be compromised there could very quickly develop a DEADLY situation - As the addition of an Extract Fan could easily cause.

If the Boiler / Water Heater is an old `Open Flued` Appliance this situation would already fall into the `Immediately Dangerous` category because of the Ventilation communicating with the Bathroom and the possibility of `Cross Ventilation` / Adverse effect on the Boiler / Multipoint Water Heater Flue.

In that situation the Boiler Gas Supply should be Immediately Disconnected and Capped Off by a Gas Safe Registered Engineer / Installer - With the permission of the Occupier / Responsible Person for the Property.


ANY Gas Appliance / Boiler / Multipoint Water Heater that is fitted in a Bathroom or Shower Room MUST be Room Sealed - a NON Room Sealed Appliance even if fitted in a Compartment which communicates / is `located in` a Bathroom or Shower Room MUST NOT have Air Vents that take Air from the Bathroom / Shower Room and allow `Compartment Cooling` Ventilation INTO the Bathroom or Shower Room.


IF the Boiler / Multipoint Water Heater IS a Room Sealed Appliance there should still usually be `Compartment Cooling Ventilation` - But this should still be either `Direct to outside Air` - OR `Into the Room` - NOT some of Both.


Having written a few pointers about this - obviously without knowing the Appliance details - I must urge You to get the Surveyor to order a Gas Safety Inspection of the Boiler / Multipoint Water Heater and the Compartment Ventilation.


You are quite right to have questioned this and I Compliment You on your Professionalism - it is great to see another Professional Tradesman who considers the Safety of Gas Appliances and how their Works / Installation of Fans etc. could possibly have an effect on them.


There are now specific Ventilation regulations within the Building Regulations - and when CORGI were in operation they kept `Informing` Me that I should join their `Competent Persons` Scheme for Ventilation if I was responsible for any `Mechanical Ventilation` regarding Homes where I installed Heating Systems / Gas Appliances.


I hope that this has been Helpful needasparks - I would definitely involve the Surveyor - even If there has previously been a Gas Safety / Landlords Gas Inspection / Certificate this situation should be Checked AGAIN.


NO Surveyor who is acting Professionally would ever decry You for bringing this to their attention - You could be Saving Lives ! and also if they arrange for a Gas Safe Engineer to Inspect and there ARE Problems the Surveyor will probably take the `Credit` for HIS Findings.


Regards,


Chris - Heating Engineer and Gas Safe Registered Gas Engineer
 
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  • #10
Thanks Chris, points duely noted. as said i did post on the plumb side of the site to get their input but as mentioned i did the normal numbty thing and forgot photo's or boiler model to help get answers as it could be a storm in a teacup but just seemed wrong seeing the vents around it give me boiler wiring anyday. I'm saying old boiler as it had the pilot light in the window and red/white buttons to light so looked old style to me.
Will give more info tomorrow when on site again to start works as was only there just to see job today.
thanks for your time to post.
 
Thanks Chris, points duely noted. as said i did post on the plumb side of the site to get their input but as mentioned i did the normal numbty thing and forgot photo's or boiler model to help get answers as it could be a storm in a teacup but just seemed wrong seeing the vents around it give me boiler wiring anyday. I'm saying old boiler as it had the pilot light in the window and red/white buttons to light so looked old style to me.
Will give more info tomorrow when on site again to start works as was only there just to see job today.
thanks for your time to post.

"Hello again needasparks",

I am glad to be of help - it may be that the Appliance is a Multipoint Water Heater ? - from your reference to `Multipoint` - BUT - even so if this Appliance is NOT Room Sealed and although the Combustion Air may be entering the Appliance from the Air Intake section of the Flue Terminal [?] - the Compartment Cooling Ventilation should still NOT be via the Cupboard Door Vents into the Bathroom.

Even IF this is the situation regarding the Gas Appliance - it still needs to be brought to the Surveyors attention.

As Professional as I consider Myself to be regarding `Remote Advice` on Gas Installations / Appliances I MUST advise that A Gas Safe Registered Engineer should carry out a Gas Safety Inspection of the Gas Appliance / Location / Ventilation configuration etc.

Changing this situation to have Vents communicating to Outside Air Only can sometimes be awkward - depending on whether there is room to Install the Correct / Calculated Vent Sizes - although obviously this would not be included in Your Works.


Regards,


Chris
 
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  • #12
Well after todays visit i took some pics.







Hope that gives more info, as you can see its a small bathroom.
 

ruston

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It is a room sealed heater but well done and glad to see you were on the ball of the possibilities if it was'nt. You have a better chance to see if it complies now in light of Chris's post.
 
"Hello again needasparks",


Sorry that I could not reply to You earlier - I had a very busy Day and Evening - I did not see your message until late .


Your Photos have revealed that this is a Room Sealed Multipoint Water Heater so You have nothing to worry about regarding installing the Extract Fan regarding a possible Air Pressure imbalance causing a Spillage of Combustion Products from the Gas Appliance.

The Combustion Air is drawn in from Outside Air via the Air Intake Ducting which forms part of the Flue.


There IS however the very real possibility that the Extract Fan will cause a `Cross Ventilation` of the Boiler Compartment - Because it will act upon the Air Vents in the Boiler Compartment Door and because there is an Air Vent to Outside Air this may well cause Air to be drawn in from outside.

We might all think in our Professional Judgement / Common Sense that this could NOT possibly cause any problem for either the Boiler or the `Cooling Ventilation` for the Boiler Compartment - BUT according to the Gas Safety Regulations and the correct procedure for Ventilating a Compartment containing a Gas Appliance the existing Ventilation configuration is Incorrect.

Even though the Gas Appliance is a Water Heater and as such would not be Firing for long periods of time - as would a Heating / Combination Boiler in cold temperatures - the Regulations still apply regarding `Correct Compartment Ventilation`.


I would suggest that You let the Surveyor know that you did some research to ensure that the Gas Appliance was NOT of a type which would be adversely affected by the Installation of the Extract Fan and that You have been advised by a Gas Safe Registered Engineer about the `Cross Ventilation` that exists in the Boiler Compartment / Cupboard.

Then I suspect that He will arrange for A Gas Safety Inspection - by a Gas Safe Registered Engineer - to `Cover Himself` / get an Inspection Report - which SHOULD state what I have written here about the Compartment Ventilation.

One of the main things that Correctly Calculated and Installed Compartment Ventilation is designed to do is to prevent the Boiler / Water Heater Casing from becoming Too HOT and gradually causing the [Room Sealed] Casing SEAL from degrading - and becoming No longer `Room Sealed` - IF that did occur it would obviously become a Serious Problem.


This will probably be viewed as `strange` - the idea that `Extra` Ventilation direct to Outside Air would be a Breach of the Correct Ventilation procedure / regulations - BUT this is an example of where there is a `Set Procedure` which has been drawn up from some VERY Scientific `Real Scenario` Testing by prescribed bodies in the Gas Safety and Utilisation sectors.

Also Ventilation for this purpose must be provided from the same `Pressure Zone` - obviously Ventilation direct to Outside Air would NOT be in the same Pressure Zone as that which `Enters`/ `Exits` the Compartment from the Bathroom.


The `Compartment Cooling Ventilation` must EITHER be ALL to Outside Air - Or ALL to Internal Space - the Bathroom - And the Vents must comply with the Correct Sizes for Cooling the Compartment in relation to the Appliance - NOT just `Any old Vents` top and bottom.


I have to advise You to bring this to the attention of the Surveyor - For Professional reasons - obviously You must decide what to do with the Information.


I hope that I have been of some help needasparks - and that I have not Bored You and other Members with My very long Posts about this - But I felt that I should explain about the Compartment Ventilation - especially as the Extract Fan may well cause `Cross Ventilation` of the Compartment / Cupboard.


Regards,


Chris - Heating Engineer and Gas Safe Registered Gas Engineer.
 
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telectrix

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while a lot of your post, chris, is over my head, still an excellent and useful post for future reference.
 

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