Author Topic: Clearance between furnace intake and any other exhuast  (Read 1012 times)

Offline vyasji

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Clearance between furnace intake and any other exhuast
« on: June 25, 2016, 05:40:45 PM »
I have purchased a new home and the builder provided the central vacuum rough in.

When I called a vacuum installer, the technician said the exhaust of vacuum system is just two inches away from the furnace intake which is against the code.

He said as per the code there should not be any exhaust within 3 feet of any of the furnace intake (air or combustion).

I don't have any proof regarding this and my builder is saying there is no code violation.

I tried looking as Gas Code 2010 but is specifies for the moisture exhaust ( which is generally referring to the Dryers) I need the details on clearance between Central vacuum system exhaust and furnace intake.

Can somebody provide me the code reference if there is any?
Thanks.

Offline walker

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Re: Clearance between furnace intake and any other exhuast
« Reply #1 on: June 25, 2016, 06:28:02 PM »
as far I know there is no code pertaining to the exhaust of a vacuum.  I think some others here can chime and confirm that.

Offline Porcupinepuffer

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Re: Clearance between furnace intake and any other exhuast
« Reply #2 on: June 25, 2016, 07:33:26 PM »
I've never personally seen a central vacuum yet that was exhausted to the outdoors. I don't see anything in the codebook for it. But perhaps there's some confusion with the code by the technician.
Maybe he has seen in the owners manual (if it were a Carrier) it may say "Furnace combustion air intake clearance to a water
heater vent, dryer vent or other types of appliance exhaust".

He may be accustomed to a central vac being labelled an appliance, but it's not.

Appliance in our codebook is defined as a device that consumes or is intended to consume a gas and includes all valves, fittings, controls and components attached or to be attached to it.
Maybe he's thinking of a moisture exhaust from a dryer or spa.

Is this an abs/636 pvc type of intake that is directly attached to the furnace? or a larger 4" or so fresh air intake? What's the model of your furnace?

Offline Admin

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Re: Clearance between furnace intake and any other exhuast
« Reply #3 on: June 27, 2016, 11:40:40 AM »
I would agree, there are no codes about clearances to a vacuum exhaust.

Clauses 7.5.2 and 8.3.7 apply to moisture exhaust ducts.

Quote
Clause 7.5.2 - A moisture-exhaust duct shall not terminate within 3 ft (1 m) in any direction of any pressure regulator vent termination or fresh-air intake.

Quote
Clause 8.3.7 - An air-supply opening shall not be located within 3 ft (1 m) of a moisture exhaust duct.
Note: A moisture-exhaust duct (e.g., a gas or electric clothes dryer discharge; spa exhaust) is considered to interfere with the combustion air intake when located within 3 ft (1 m) of the air intake.

Offline vyasji

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Re: Clearance between furnace intake and any other exhuast
« Reply #4 on: June 27, 2016, 12:43:55 PM »
Thanks for your inputs.
I also tried looking at various sources that says about moisture exhaust and furnace intake clearances but couldn't find anything on the central vac. I am going to install Vacuflo 466Q model which needs to be exhausted outside.

As per the technician 5% for the dust it accumulates goes to this vent and if it is near the furnace intake (it is just 2 in. away from furnace combustion intake)  it can foul furnace sometime or we may have dust being circulated in the house.

I called city of Edmonton to inquire about it and the technical advisor told me that the dryer and central vacuum falls under the same category and needs to follow the 3 ft clearance regulation. He didn't gave me any specific code detail.

This is getting confusing as I found on union gas guide for gas meter regulator that says " The following items do not conflict with the meter placement and require no clearance from a gas service regulator - HRV exhaust, Central Vac exhaust, Fixed window or fixed part of sliding doors, range hood exhaust, bathroom exhaust.  "

I need some proof for what is being said by city so that I can pass it on to my builder.

Any help would be appreciated.
Thanks

Offline Admin

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Re: Clearance between furnace intake and any other exhuast
« Reply #5 on: June 27, 2016, 05:40:44 PM »
Get the bureaucrats working and have them provide a gas, bylaw or building code reference.

I would say it's not ideal for the furnace intake to suck in dust from the vacuum exhaust, as it can cause poor combustion which results in lower furnace efficiency.

It's likely the furnace will not be heating everytime the vacuum is used.  If you're living around new construction, the furnace intake has already been sucking in dust for some time.

An easy option may be to have the builder snorkle the furnace vents away, and have the vacuum installer install a fitting to divert any exhaust away from the furnace intake.  Or just have the builder relocate the vacuum exhaust and replace one piece of siding or brick.