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Unsafe through-wall side wall vent chimney © D Friedman at InspectApedia.com Side Wall Vent Chimneys & Flues
Direct-Venting Heating Appliance Chimneys & Flues

  • POST a QUESTION or COMMENT about the installation or diagnosis of sidewall vent or direct vent chimney or flue exhaust systems for heating appliances: oil, gas, other fuels firing heating appliances & fireplaces

Direct vent chimneys or exhaust for heating appliances:

This article describes side wall vent systems for conventional & mid-range-efficiency heating boilers, furnaces & water heaters. We include for comparison, low temperature side wall vent systems used by high efficiency or condensing boilers, furnaces & water heaters.

We explain the difference between side wall or direct venting for conventional/mid-range efficiency oil or gas burning heaters and side wall vented high efficiency condensing heating appliances.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Guide to Direct Vent or Side-Wall Vent Chimneys & Flues

Oily soot at a direct vent or sidewall vent exhaust at a building in northern Minnesota (C) Daniel Friedman at InspectApedia.comDirect-venting or side wall vent chimney and flue systems are a method of venting the exhaust gases from a heating appliance directly out through the side wall of a building while eliminating the need for a vertical chimney of any sort.

Gas or oil fired side wall power vents are provided by several manufacturers listed at the end of this article.

Watch out: if you see thick soot and smoke at your sidewall or direct-vent exhaust flue or chimney (like the black soot around the vent in our photos here and at page top) the heating equipment vented by this exhaust system is not operating properly and it's probably unsafe

[Click to enlarge any image]

Article Series Contents

Side Wall Vent Equipment for Oil Fired Boilers, Furnaces, Water Heaters

For safe and clean sidewall venting of oil fired heating equipment the vent system incorporates a power vent fan to assure that gases leave the building side wall with sufficient velocity to avoid sooting or otherwise harming the wall.

The system, such as Tjernlund's SIDESHOT® series of power vents draws outdoor air thorough the outer passage(s) of a multi-walled vent plenum, cooling the exhaust gases as they pass through the vent.

Risk of fire and heater malfunction with improperly installed or site-built side wall vent systems

One look at the "do-it-yourself" attempt at side wall venting (photo at left) makes clear why the proper equipment is needed to vent an oil fired appliance directly though the building wall. Avoid a building fire with do-it-yourself though-wall chimneys & flues

Our soot stained wall photo (photo at left ) shows what happens at a direct-vented oil-fired heating system when there are multiple errors and unsafe conditions including:

The heater is not working properly and needs immediate service as it is blowing thick dense sooty smoke

The through-wall metal flue vent and "chimney" appears to be a home-made adaptation rather than a listed and approved direct-vent device.

The effects of this home made direct-vent "chimney" are quite visible: the siding on the building has been thickly coated with soot. If you (click to) enlarge the photo you will also see some interesting reverse thermal tracking effects marking the wall studs. This is an unsafe installation that needs immediate repair.

Watch out: the photograph above illustrates an unsafe thorough-wall vent for an oil fired heating appliance.

See SOOT on OIL FIRED HEATING EQUIPMENT for more information.

We have received or read building owner complaints that sidewall venting has "ruined the building siding" or "stained the siding" but in our OPINION such problems occur because of an improper installation or improper heating equipment maintenance.

Side Wall Power Vent Equipment for Gas Fired Boilers, Furnaces, Water Heaters

Vent Drip (C) Daniel Friedman

Our photo above shows an Energy Kinetics oil fired heating boiler vented using an OEM direct vent system.

Shown below is the exterior wall of the same installation.

The stained wall photo (photo below) shows what can happen at a direct-vented high-efficiency heating boiler if the vent is not properly sloped through the wall.

Condensate accumulates in the vent pipe, dissolves flue gas deposits, and ultimately leaks both outside and back into the equipment.

Vent Drip (C) Daniel Friedman

To repair this mistake the installer will have to disassemble the entire vent system, and either remove a bit of masonry block from the bottom of the present wall opening or change the interior flue vent connector piping to slightly raise the inside end of the through wall vent - one or the other - to obtain proper condensate slope and condensate handling on this equipment.

[Click to enlarge any image]

Direct or Sidewall Vent Conventional Oil or Gas Fired Heater Exhaust compared with a High Efficiency Condensing Furnace or Boiler

Exhaust or venting of heating appliances may be horizontal, direct through a building side wall, or vertical, up through the building roof. But what is the difference between Direct Exhaust and Direct Venting ? Weil-McLain makes the following important distinctions: [10]

Definitions of Sidewall or Vertical Direct Venting compared with Direct Exhaust

Direct Venting uses a power ventilating blower or fan (and in some models a heat exchanger plenum to cool outgoing gases passing through the building wall (sidewall direct exhaust) or roof or through an existing unused chimney through which a vent pipe is passed (vertical direct exhaust).

Combustion air for heating boilers or furnaces is drawn from outdoors through a dedicated air intake pipe or duct (the small diameter pipe in the pair at left of our photo below).

Definitions of Sidewall or Vertical Direct exhaust

Direct exhaust venting draws combustion air from the utility room or boiler room around the heating appliance and vents appliance exhaust out through a building sidewall or through the roof using an approved or listed B-vent, metal chimney, or similar materials. Combustion air is provided to the heating appliance from the space surrounding the equipment.

Sidewall direct exhaust heating appliances

Sidewall direct exhaust uses a B-vent or other listed or approved metal or even plastic flue vent connector and metal chimney materials to vent outgoing combustion gases through a building side wall (sidewall direct vent).

A blower or power vent draws combustion air in to the heater and a power vent pushes exhaust gases out through a separate or dedicated exhaust flue.

The heating appliance vents directly out through a building side wall, powered by natural draft provided by the heating equipment, typically using a single wall metal flue or chimney or a B-vent.

This venting method, typically for gas fired boilers, can be used only by certain heating appliance models such as Weil-McLain's CGs boilers excluding the CGs-4E model.[10]

Vertical direct exhaust-vented heating appliances

Unsafe sidewall vent (C) Carson Dunlop Associates

Vertical direct exhaust is a similar installation to the sidewall direct exhaust vented vertically, typically up through the building roof. This heater venting system, typically for gas fired boilers, is used only by certain heating appliance models such as Weil-McLain's CGs boilers.

Image at above left courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ]. [Click to enlarge any image]

Safety Controls at side wall power venters include

[Click to enlarge any image]

Safety controls and power vents for gas fired heating appliances are certified by the AGA, the American Gas Association.[6]

Vent condensate freeze (C) Daniel Friedman

Watch out: don't confuse direct vent heating equipment with the through-wall venting and air intake of high efficiency boilers and furnaces.

Both types of heating systems can vent horizontally through a building wall, but the exhaust products of high efficiency or condensing boilers and furnaces are generally cool and have different venting and combustible clearance specifications.

See CONDENSING BOILERS/FURNACES

also
see CONDENSING BOILERS/FURNACES DAMAGE.

What's the Difference Between Venting a High Efficiency Condensing Boiler or Furnace or Water Heater with a Mid-range or Conventional Heating Boiler, Furnace, or Water Heater?

In comparing the venting of exhaust gases from a high efficiency furnace, boiler or water heater with the venting of exhaust gases from a conventional heating system it will be immediately obvious that the high efficiency equipment exhaust is produced at a low-enough temperature that it is vented through comparably small-diameter plastic piping rather than a cooled, fire-protected metal heating vent.

What can be confusing is that some mid-range efficiency heating equipment may vent through a (larger diameter, say 4") plastic heater vent referred to as HTPV (high temperature plastic vent) chimneys.

We illustrate an HTPV system at below left and a high efficiency plastic direct vent system at below right (Image courtesy of Carson Dunlop Associates ).

Unsafe sidewall vent (C) Carson Dunlop Associates

More details about HTPV and a product safety recall are

at PLASTIC Plexvent / Ultravent RECALL.

HTPV high temperature plastic vent

Vent Clearance Requirements for Direct Vented Gas Appliances

Direct vent clearance distances sketch - adapted from Thermo Products & NFGC at GAS APPLIANCE / HEATER DIRECT VENT CLEARANCES we provide a complete list of required clearance distances between the air intake or combustion gas exhaust vents for direct vented heating appliances. Illustration adapted from Thermo Products installation instructions - click to enlarge this or any other image or photo at InspectAPedia. [15]

[Click to enlarge any image]

Some highlights include:

 

Importance of Proper Slope on Heating Equipment Exhaust Vent Piping

Vent condensate freeze (C) Daniel Friedman& Protection from Blockage by Snow, Ice, Shrubs or Wind

Watch out: Both direct vent chimney specifications (discussed beginning at the start of this article

at DIRECT VENTS / SIDE WALL VENTS) and

condensing boiler or furnace vents (shown at below left and discussed

at DIRECT VENT GAS HEATER IMPROPERLY INSTALLED must be installed following the manufacturer's specifications.

Otherwise there is risk that condensate either freezes (if you're in a freezing climate) to block the heater's exhausts (you lose heat) or to produce dangerous carbon monoxide gas in the building.

Specifications for direct vent and condensing boiler vents may specify that the vent line slopes to indoors where condensate is to be disposed-of at an interior condensate handling system or drain, or they vent may be required to slope to the outside.

Our illustration at left shows the plastic pipes of two types of direct vent heating appliances protruding through a building sidewall.

We can tell from the height above ground that the heaters are most likely located in the building basement.

The pair of plastic lines in the left of the photo are an air intake (the shorter protruding plastic pipe) and exhaust vent outlet (the longer plastic outlet pipe). The wider single round plastic vent at the right side of our photo is venting a second appliance, perhaps a water heater.

Watch out: We can also see that as with the gas appliance power vent shown in the previous section, this high efficiency heating system condensate is also not being properly drained from the left hand condensing heater - instead of condensate running back into the building and into a building drain, this pipe is sloped so that condensate runs out of the end of the plastic vent line.

The problem with this arrangement becomes evident in cold weather as condensate freezes and the ice formed can actually block the safe venting of exhaust gases.

Watch out: Ice formation at sidewall vents is not the only cold weather hazard for this equipment. Our photo at left shows that the vents are less than 24 inches from the ground. In climates where snowfall may occur at depths capable of covering the air intake or sidewall vent outlet, Vermont Gas and Thermo Products both warn that it is critical to keep sidewall vents clear of snow-cover.

Blocking the combustion air intake or exhaust outlet by accumulated snow, ice, or even shrubs or piled leaves can result in dangerous. potentially fatal carbon monoxide gas poisoning of the building occupants.[13][15]

You should inspect the exhaust vent and combustion air intake vent for blockage at least annually, and we recommend further inspection in winter for blockage by snow or ice:

The vent and combustion air terminations shall be checked periodically, at least at the start of each heating season, for restriction or blockage from foreign material in the exhaust vent or in the air intake piping. Clean the air intake and vent terminations when necessary. [15]

Protect direct vented appliance vents from becoming blocked by snowfall

Rooftop installation of direct vent intake and exhaust vents - Thermo Products, InspectAPediaAs you can read in our citation of direct vent and sidewall vent clearance distance requirements in the FAQs below,

The outlet/inlet of the vent and air intake terminations shall be a minimum of 12 inches above highest anticipated snow level. The vent outlet must be installed a minimum of 12 in. above the air intake inlet.

Terminations must also be kept clear of any leaves, weeds, combustible materials, snow, and ice build-up. [15]

and Thermo Products further recommends:

In geographical areas with considerable snowfall, it is advisable to locate the vent terminal much higher than the minimum 12-inches above ground to prevent blockage by snow accumulation or drifting. [15]

For at least some heating appliances and manufacturers, and to solve vent clearance difficulties when your installation cannot meet the specifications in the Gas Code, manufacturers' specifications, or local building codes, roof vent termination kits are available.

Notice that the illustration (left) of roof-vent termination of direct-vent appliance air intake and exhaust does not show the necessary flashing & sealing to avoid roof leaks.

Illustration adapted from Thermo Products installation instructions. [15]

The furnace may be vented vertically through the roof. The outlet/inlet of the vent and air intake terminations shall be a minimum of 12 inches above highest anticipated snow level. The vent outlet must be installed a minimum of 12 in. above the air intake inlet.

The combustion air intake shall be installed upwind of the vent outlet when exposed to prevailing winds. The exhaust vent and combustion air intake can be a minimum of 3 in. and a max. of 24 in. apart. [15]

Watch out: when chimneys or vents pass through building floors and roofs above, additional fires stopping may be required.

Protect direct vent appliances from wind:

Wind protection for direct vent appliances - Thermo Products Installation Instructions

The combustion air intake shall be installed upwind of the vent outlet when exposed to prevailing winds.

Avoid locating the vent terminal on a wall facing prevailing winds and wide-open areas.

When impractical, choose a location that protects the vent from strong winds, such as behind a fence or hedge. [15]

Comment: Keep hedges, fencing, or other wind barriers far enough away from the air intake vent to avoid obstructing air intake, and keep hedges far enough away to avoid plant injury from the heat of exhaust gases.

Illustration adapted from Thermo Products installation instructions. [15]

Avoid locating the vent terminal over areas where dripping of condensate, or small pools of acidic condensate, could create a problem. [15]

Comment: OPINION: an exhaust vent that is dripping condensate to the outdoors in freezing climates risks dangerous blockage by ice formation.

Safety Warnings Regarding Combustion Air Supply Source for Direct Vented Heating Boilers/Furnaces

Weil Mc-Lain [10], Thermo Products [15] and other manufacturers warn that if the heating appliance is in an area where local indoor-area-supplied combustion air is likely to be contaminated the installer must pipe an outdoor combustion air supply to the heating boiler (or other heating appliance) combustion air intake port.

Watch out: There are critical concerns with combustion air contamination for heating appliances:

Combustion air that is contaminated with corrosives can damage the boiler by corroding the heat exchanger or other components. The result can be worse than damage to the equipment. Corrosion that leads to flue gas leaks can leak potentially fatal carbon monoxide or other gases into the occupied space of the building.

Other combustion air contaminants that are flammable or themselves combustible could lead to an actual fire or explosion.

Examples of corrosive contaminants include

If your building contains any of these or other corrosive or explosive products and if you cannot remove them from the locale, an outside combustion air supply must be piped to the heating appliance air intake.

Watch out: also make sure that the combustion air supply outdoors is not itself close to a source of corrosive or explosive materials.

Manufacturers & Manuals: Gas & Oil Direct Vent, Side Wall or Through Wall Vent Chimney Systems

Rutland sealant for direct vent chinmneys (C) InspectAPedia.comDirect sidewall vent heating appliance manufacturers & products can be listed here at no fee. CONTACT US to provide information or technical comment.

Listed special gas vent systems that comply with UL-1738 & UL S636 and in Canada, certified by CSA are the only vent systems that can be used with Weil Mc-Clain's CGs heating boilers. Depending on the brand and model, your heating appliance may have similar restrictions so be sure to read the installation instructions with care.

Clearance Distance at Exterior Vent Termination of a Direct-Vent Gas Fireplace

We moved this data to a separate table now found

at GAS FIREPLACE VENT CLEARANCE REQUIREMENTS Separate Table for Direct Vented Gas Fireplaces

Reader Question: is this direct vent gas fireplace outlet too close to my air conditioner?

See CLEARANCE DISTANCE, HVAC where a reader commented that his building inspector did not accept the safety of the installation shown below. We agreed.

Gas fireplace vent too close to air conditioner compressor/condenser unit (C) InspectAPedia.com

Reader Question: is this direct vent outlet too close to my window?

Direct vent wall inlet / outlet clearance to window (C) InspectApedia.com BL

I googled “carbon monoxide plastic flue roof top side house” and came across your website with relevant information. I have a question below, and please let me know if there is a fee for answer and what is the fee. I would like to address my concern of CO coming out from side of house, even if it is per code.

Breathing in CO is of great concern to me. Comparing it to car exhaust does not comfort me, as we would not a stationary car for the exhaust gas with CO at same place as plastic flue side wall vent. Please assist answer the questions below. Thank you. B.L. by private email, 2016/03/30

Reply: here are typical clearance distances for a direct-vent gas fired appliance vent opening to an operable window

Direct vent gas vent clearance required depend in part on the size in BTUs (BTUH or thousands of BTUs per hour input rating) of the heating appliance.

We marked on your gas vent photo the two measurements that are typically made: the vertical distance to the window and the horizontal distance to the window from the nearest point of the gas vent.

For a typical gas fired water heater, the distance from the vent outlet to some building features are a bit different depending on whether your home is in Canada or the U.S. or in another country and jurisdiction.

But for operable windows, both countries use the same guideline: the distance shown by the red arrows needs to be 3 feet for heating appliances over 100,000 BTUH.

These clearance instructions were in the General Venting Requirements installation manual for your vent system, in the document that you sent to me (page 65), as

Direct Vent Exhaust for Heating Flues: Installation & Inspection Questions

This topic has moved to DIRECT VENT INSTALLATION, SNAFUS & SPECS

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2023-12-15 by InspectApedia Publisher - technical support at Navien agrees that the installation is improper

@Allen,

Update: technical support at Navien is in agreement that the installation is improper. Here's what Navien technical support replied to my query:

---

Looking at the photo the unit would need further termination distance to prevent the exhaust gases from recycling into the unit causing it to self-cook.

Normally you want at least a 1ft distance vertically and horizontally for the venting - If another furnace venting is there it would need the exhaust to be moved away.

- Navien Technical Support, by private email to InspectApedia editor, 2023/12/15

---

By "self cook" I think the technician means overheat, which can damage or destroy the equipment and which thus also be a safety hazard.

On 2023-12-14 by InspectApedia Publisher

@Allen:

About your Lennox EL196 gas furnace, if you don't have the installation manual (which gives clearance distances for direct vent on p. 26-30) and also the user's information manual, you can download both of them at our Lennox Manuals page

LENNOX HVAC MANUALS & PARTS GUIDES

Look for these two manuals
Lennox EL196UHE SERIES GAS FURNACE USER'S INFORMATION MANUAL [PDF] (2018)
LENNOX EL196UHE GAS FURNACE INSTALLATION MANUAL [PDF] (2021)

You'll see that your installation seems to violate clearances given in that installation guide as well.

On 2023-12-14 by InspectApedia Publisher

@Allen & other readers: we posted a technical request at Navien's contact page asking for a review and comment of your installation photo.

On 2023-12-14 by InspectApedia Publisher

@Allen,

Let me know if we have any errors in the labeling on this copy of your photo.

improper venting for gas appliances (C) InspectApedia.com Allen

On 2023-12-14 by InspectApedia Publisher - Navien's direct vent heater clearance distances table

@Allen, and other readers:

and here's the rest of Navien's direct vent heater clearance distances table

Navien direct vent heater clearance distances table

On 2023-12-14 by InspectApedia Publisher

@Allen, and for other readers,

here is Navien's Direct Vent Clearance Distances table. You'll see that it's similar to other illustrations like https://inspectapedia.com/heat/Direct_Vent_Clearances2c.jpg

and that we give in detail at

GAS APPLIANCE / HEATER DIRECT VENT CLEARANCES Separate Table for Direct Vented Gas Appliances

from other sources that we cite at InspectApedia.

Navien terminal clearances for direct vent installation

On 2023-12-14 by InspectApedia Publisher

@Allen, and other readers,

Here's p. 57 from the Navien Manual, showing direct sidewall venting - notice that the drawing does not show other mechanical or non-mechanical air intakes or vents close by.

p. 57 from the Navien Manual, showing direct sidewall venting

On 2023-12-14 by InspectApedia-911 (mod) - building code official may help contractor do required repairs

@Allen,

Thank you for the helpful discussion.

It's unfortunate but true that sometimes just following the correct instructions isn't enough to motivate the contractor to go to the trouble of redoing a job but a building code official stepping in can give them a little boost in the right direction.

On 2023-12-14 by Allen

@InspectApedia Publisher, Thank you for the detailed reply. I looked at the manual you sent and Navien shows the optional low profile two-pipe sidewall venting on page 57 which doesn't appear to need 12" between the two water heater vents.

But I see the required 3 feet between the exhaust vent of the water heater and the house non-mechanical air intake. So it looks like the company installed it wrong. I have asked them to re-install the water heater.

However, they are giving the cold shoulder right now. I'm wondering if I should request the city inspector check it out. Since the company did get a gas permit to install it.

On 2023-12-13 by InspectApedia Publisher - does the venting for multiple gas appliances have proper clearances

@Allen,

I don't know what happened to my long reply with drawings and illustrations that I posted in reply to your question and photo so while I recreate that let me just recap as follows:

The direct venting equipment in your photo looks as if it may well be improper, unsafe, and perhaps installed by someone who was not expert on this topic.

Taking JUST the direct vent water heater data that you gave for example (I asked for the water heater brand and model) we found that the manufacturer expects a minimum of 36" between the water heater's exhaust vent and its combustion air intake vent.

I also commented that the water heater elbow in your photo would normally face down (that's usually the combustion air inlet); when it faces horizontally or maybe even slightly "up" as I think I see in your photo, there is risk of rain or snow entry, and in cold weather, freezing that could obstruct the inlet.

I asked that you let me know what you're told as these are important life-safety questions that may help other readers.

I looked at that Navien heater IO manual and that's where I got the 3 ft separation distance.

Here's our page that has the manual for your Navien water heater

NAVIEN WATER HEATER AGE & MANUALS

And from this manual

https://inspectapedia.com/plumbing/Navien-NPE-A2_S2_Installation_Manual.pdf

we have this example of the 36 inch clearance requirement.


I ended by saying that at the very least you want to be sure that you have working, tested, properly installed and located Carbon Monoxide Detectors (CO detectors) and smoke detectors in the home and I added that you might call the technical support for your water heater to ask the company rep to take a look at your photo.

Navien direct vent horizontal installation

On 2023-12-13 by InspectApedia Publisher

re-posting a lost earlier comment

AUTHOR: Allen (no email)

COMMENT: @InspectApedia DF, Thank you for your response. I have a 199k BTU, Navien NPE240A2 tankless hot water heater (It has the exhaust vent on the top left, and intake with the elbow on the right). The big tin vent on the far right is fresh air going into the house. Then I have a Lennex EL196 45k BTU furnace (that's the oval shaped venting on the bottom).

On 2023-12-12 by Allen

Hello, I'm wondering if the venting is installed correctly on my home. The bottom oval shaped terminal is for the 45k btu gas furnace. Above that is the exhaust, intake for the 199k btu tankless hot water heater. Beside those is the metal air intake for the house, what I guess would be called non-mechanical air intake.

improper venting of multiple appliances (C) InspectApedia.com Allen

On 2022-05-30 by InspectApedia-911 (mod)

@NewtownGuy,

Air intake & exhaust vents for direct vented heating equipment.

On 2022-05-30 by NewtownGuy

There is a photo of 3 white PVC pipes, one much larger in diameter than the others, on the side of a building that has white siding. What are the functions of the 3 pipes ?

On 2022-01-20 by Inspectapedia Com Moderator - direct vent furnace exhaust condensation ruined the paint on my siding

@Mark B,

That's an annoying problem I agree. I don't have an instant, perfect solution, as frankly it's not a problem that we've encountered before.

Are there specific site conditions such as unusual moisture traps, roof overhang, weather exposure, wind direction at cetera that could be contributing to this problem?

And I expect you will confirm that this is a gas fueled heater that's being vented.

Before attacking a fix to this direct vent condensation on wall problem it might be worth asking your heating service company to confirm that there's no abnormal level of condensation being produced, such as by an improper burner adjustment or a fuel problem.

It's important to rule out a safety or heater malfunction before we treat the symptom.

Then, If your manufacturer agrees that it is safe to do so, you might be able to improve matters by extending the vent further from the wall. I wouldn't do that without checking with him.

I might also be sure to use a pigmented stain rather than an actual paint on siding as that's much more resistant to peeling.

On 2022-01-20 by Mark B

How do I prevent direct vent furnace exhaust from condensing on my siding? The moisture condenses on the siding then the freeze/ thaw cycle ruined the paint.

The "fix" was to extend the pipe but still get condensation and frost in cold temps. No it is not from an uninsulated wall this is on a wall with 6 inches of spray foam insulation

condensation from direct vent furnace exhaust is ruining paint on siding (C) InspectApedia.com MarkB

On 2021-11-10 by Inspectapedia Com Moderator - Do I have to use B-vent?

@Daniel K Majka,

Not necessarily, but let's identify the specific furnace brand and model and then look at its installation manual where venting requirements will be detailed for that very heater. A "generic" answer may be wrong.

On 2021-11-10 by Daniel K Majka

I live in Michigan. I'm installing a 80% furnace in my basement. My exhaust vent is 8 feet from the chimney. Do I have to use B-vent?

On 2021-08-06 by inspectapedia.com.moderator - Which way does the direct-vent, sidewall-vent, or combi-vent for my heating equipment slope?

@Bob,

Thank you for a helpful question that I'd phrase (for other readers as )

Which way does the direct-vent, sidewall-vent, or combi-vent for my heating equipment (boiler, furnace, water heater) slope?

To be fully confident of a right answer it'd help to know the vent & boiler brand and model so that we could both consult the installation instructions from the manufacturer.

But in most instructions we see that the vent slopes "down" towards the boiler and "up" to the exterior: here's a quote from the Burnham ESC instructions - as an example:

Horizontal vent pipe must maintain a minimum ¼ inch per foot slope down towards boiler. (That's the same as sloping "up" towards the outdoors)

Also see

SLOPE REQUIREMENTS for direct-vented chimneys & plastic vents

If you have a condensing boiler or furnace, also see

CONDENSING BOILER/FURNACE CONDENSATE DRAIN

On 2021-08-06 Bob

Should the intake pipe on a combi boiler be sloped so it drains outside or should it be sloped to drain back to the appliance?

Thanks

On 2021-04-28 by danjoefriedman (mod) - seal of flue vent connector into chimney thimble is deteriorating

@Linda,

Just how durable the seal of flue vent connector into chimney thimble will be depends on a number of variables besides the quality of the original sealing cement, including area moisture, chimney top leaks, mechanical disturbance, and probably other factors.

Considering the cost of a bucket of chimney seal-cement and the time involved, this ought to be a trivial repair that any handyman and many homeowners can do - and perhaps with less total time and aggravation than arguing with the installers if they don't want to return to the job.

At Lowes this container of Oatey Chimney repair cement that's more than you need costs about $13. U.S.

Oatey Chimney repair cement

On 2021-04-28 by Linda

We had a new flue put in our chimney for our gas water heater and gas furnace a few years ago. The chimney people replaced the vent from the furnace/water heater to the wall to the chimney.

When they patched it into the wall, they used what looks like a gray colored cement. Now, a few years later, the circumference of the cement patch is peeling away from the basement fieldstone wall.

Are the chimney people responsible for fixing this? What causes this to happen?

On 2020-12-20 by danjoefriedman (mod)

I don't have a clear picture of a situation. Is this a duplex house?

On 2020-12-20 by Maire Siordan

neighbours side wall kitchen vent is directed on to my shared front porch. - is that allowed by gas or any authorities/



...

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DIRECT VENTS / SIDE WALL VENTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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