Pellet stove help

[Charles Hellickson]

This appears to be a 4" PVC pipe coming up through the chimney for the pellet stove. Can someone explain this to me? I am not real familiar with pellet stoves and this does not look right to me. Any help would be appreciated.

[James F. McKee]

I've only seen them direct vented like the gas units....I think I'd reccomend checking manufacturers specs on that installation....jmo....jim

[Marcel R. Cyr]

Charles;

This might help a little.

http://www.nevelsstoves.com/articles...llet-stove.htm

Venting your Pellet Stove

Venting your new pellet stoves is crucial for optimum operation of your stove.

To begin let's first talk about the different types of vent pipes in the market. There are five different types of vent pipe used in the heating industry.

1. Gas vent pipe, which uses aluminum for the inside wall of the chimney. The chimney itself looks very similar to Pellet Vent pipe. Read the label to make sure. Under no circumstance should gas vent pipe be used for Pellet Vent Pipe, as the inner wall will not stand up to the pellet vent exhaust and pipe will fail very rapidly.
2. Pellet Vent pipe, referred to as L-Vent pipe, can be purchased in 3 inch and 4 inch diameter sizes. The L-Vent pipe is the correct type of pipe for your pellet stove. The inner chimney is made from Stainless Steel and will last as long as your pellet stove.
3. Corn Vent pipe is usually for corn burning stoves however, it is OK to be used for the pellet stoves as well. Corn Vent also comes with a stainless steel inner chimney, and should last the life of the stove.
4. Manufactured wood stove pipe, classified as Class A pipe, usually comes in 6 inch, 7 inch, and 8 inch diameters. This type of pipe will also work with your pellet stove as it also has a stainless steel inner chimney. However, it is not necessary to be used for the pellet stove since this type of pipe is very expensive.
5. Existing masonry wood stove chimneys with clay liner are also classified as a Class A chimneys and comes in various sizes and must have a clay inner liner. This also works very well with a pellet stove. Pellet vent pipe can vent directly into Class A chimneys.

Having talked about the different types of pipe, we now move on to our main topic which is how to vent pellet stoves using the using pellet stove vent pipes or in conjunction with an existing chimney. The purpose of this article is to discuss how to configure your pellet stove vent System. It is critical to adhere to all clearances and recommendation from the manufacturer of the pellet stove you bought. All pellet stoves come with its own installation manual. These installation instructions are to be followed exactly, and will override any suggestion printed below. Inspectors at your local municipality based their inspections on the manuals along side any local codes that need to be enforced. As such it is imperative that the installation manual be adhered to.
First let us understand what we can not do as to the location for the termination of the vent pipe. If your planned termination location falls at any of the below described location, it is critical to select an alternative location. Do not compromise as the safety of your family and others will be at risk. 1. Less then 3 feet above any forced air inlet located within 10 feet 2. Less then 4 feet below or horizontally from, or 1 foot above, any door, window or gravity air inlet into any building. 3. Less then 2 feet from an adjacent building and less than 7 feet above grade when located adjacent next to a public walk way. Mobil home installations must use a spark arrester. 4. Termination should not be located where it might ignite trees, shrubs, dry grasses or be a hazard to children as exhaust gases can reach 500 degrees and cause serious burns if touched. 5. Do not install vent pipe into chimneys shared by other appliances, as you can get a back draft and causing the exhaust from one to the other appliances to come back into the home through the other appliance.

Pellet stoves have to push the exhaust air through the vent pipe with the stove's exhaust fan. With less restriction your pellet stove will breathe easier and burn more efficiently. First let's clarify the word restriction. Restrictions come from several different items.

1. 45 degree elbows
2. 90 degree elbows
3. Horizontal distance
4. Vertical distance
5. Elevation where you live.

A rule of thumb equation we are using has been adopted by most pellet manufactures. The equation is called the sum of Equivalent Vertical Length (EVL). All of the above mentioned venting restrictions have been assigned EVL values as follows:

1. Each 45 degree elbow = 3 EVL
2. Each 90 degree elbow and Tees with cleanout = 5 EVL
3. Each foot of horizontal run = 1 EVL
4. Each foot of Vertical run = 0.5 EVL
5. Elevations above 3000 ft with an EVL of 7 must adapt to 4 inch vent pipe.

If your installation is below 3000ft, we would need to do some math. The rule of thumb equations is that if the sum of the EVL is 15 or greater, then the pellet vent pipe would be increased to 4 inch diameter pellet vent pipe.

Of course there may be different variables to this equation that we used, but still it works quite well. Let's try out this equation using several different typical installation configurations we encounter.
The first typical installation is out the back of the stove and straight through the wall with 10 to 12 inches protruding chimney past the outside wall with an installation altitude of less than 3000 ft. Do make sure that the pipe outside is clear of walkways, shrubs, and at least 24 inches above the ground. Looking back at our chart, we know that each horizontal foot equals 1 EVL. For this installation we have about 2 and no more than 3 horizontal feet which equals to no more than 3 EVL. This is of course way below the EVL of 15 so 3" pellet vent pipe would be very adequate size pipe to operate the pellet stove. The through the wall and terminate is the least desirable of installations as it is not uncommon for soot to stain the outside of the home and is more prone to high winds blowing back into the stove causing poor burning of the stove and even have the exhaust blown back into the home.
Another popular type of venting installation is in the corner of a home and an installation altitude of less than 3000ft. This is similar to the first style of installation with the addition of a 45 degree elbow is added to compensate for the corner. In this type of installation a 3 foot pipe is usually required to exit the home in order to maintain the one foot clearance on the outside. So let's start with the calculation. A 3 feet horizontal run has an EVL of 3. The 45 degree elbow has an EVL of 3 as well. Adding that together you get a total EVL of 6. This is way below the EVL of 15 so a 3" is very adequate size pipe to operate the pellet stove. The above two examples are the most common method of vent a pellet stove, because of the cost of the pipe, but also the least desirable method. READ ON. The main reason for these types of installation is cost efficiency. There is however, a word of warning. If the exhaust is located in a breeze way or prevailing wind side of the home, this would not be a suitable installation. A drawback on the through the wall and terminate installations is that it is not uncommon for soot to stain the outside of the home and it is more prone to high winds blowing back into the stove causing poor burning of the stove and even have the exhaust blown back into the home. High wind problems can be overcome by using the Up and Out or the Out and Up method of installation, but we want to terminate closer to the eve of the house or above the roof of the house.

The third and a better installation is call the Up inside the room then Out through the wall configuration. The advantage to going up and out is that the stove now has some natural draft. This advantage is more clearly seen in the case of a power outage and the exhaust fan on the stove stops. Without this natural draft this type of installation creates, the smoke coming from the live flame still going in the stove will exhaust into the home. But the draft created by this type of installation allows the smoke to be drawn up into the hot chimney and exhausted outside since hot air (and smoke) rises naturally. OK let's do the math. The home is located less then 2000 elevation. We will put a Tee with a clean out on the stove, or out side the home depending on the method decided on. A Tee is basically a 90 degree elbow, EVL=5. Next we have to go up, usually about 3 feet, EVL=1.5 another 90 degrees at the top of the 3 foot section EVL=5. Two foot through the Wall EVL=2. Now lets add, 5+1.5+5+2=13.5 EVL, still OK for 3 inch pipe.


The forth and still a very good installation is straight up through the ceiling and roof. Let's do the math. Home is located at an elevation of less then 3000 feet above sea level. One 90 degree on the back of the stove EVL=5, 12 feet of vertical pipe EVL=6. Now let's add 5+6=11, still OK for 3 inch pipe.
The fifth configuration to consider, an existing wood stove chimney on the out side of the home and we want the pellet stove to vent into the chimney. The home is located at less then 3000 feet elevation. Tee with cleanout on back of stove EVL=5. Vertical elevation in the room for this example will be 6 feet EVL=3. A 90 degree elbow to go into the chimney EVL=5. 1 foot piece of pipe to go into the chimney EVL=1. The Chimney now 90 degrees up EVL 5. Another 6 feet of vertical rise for this example for the existing chimney EVL=3. Lets do the math, 5+3+5+1+5+3= 22 EVL. 4 inch chimney is required for this type of installation. The sixth configuration we will consider is up and into an existing wood stove chimney located in the ceiling above the pellet stove. This will be the most complicated configuration to figure out, but with a knowledgeable person, this can be a very good installation with a minimum of problems. Usually the Wood Stove pipe is not directly in the right place for the pellet vent to vent into the existing pipe requiring 2 additional 45 degree elbows. This example is only an example, as every existing stove pipe will have different distances for the configuration. The stove will be located less then 3000ft above sea level. Tee with cleanout on the stove EVL=5. Vertical pipe, for this example, will be 4 feet, EVL=2. 45 degree elbow, EVL=3. 2 feet of pipe running at a 45 degree angle has an EVL of 2. 45 degree angle EVL=3. Vertical run on a one story home 6 feet EVL=3. Lets add 5+2+3+2+3+3=18 EVL. Once again we must use a minimum of 4 inch pipe.
The last configuration we will consider is for Pellet Stove Inserts. One story liner kits. The home is located less then 2000 feet elevation. 90degree on back of stove EVL=5. 15 feet of vertical elevation EVL=7.5. Do the math 5+7.5= 12.5 EVL. Two Story Liner kits. The home is located less then 2000 feet elevation. 90 degree on back of stove EVL=5. 25 foot vertical liner pipe EVL=12.5. Let's do the math 5+12.5=17.5 EVL. A 4 inch liner is required for a two story home. As you can see, using the EVL equation it is not hard to find out for yourself what your venting requirement for your stove. We hope this article gives you some guidelines in the placement for the venting options for the pellet stove of your choice.

Marcel

[Charles Hellickson]

They have a pellet stove insert into an existing fireplace, so basically they used the pellet vent pipe into the existing chimney which should be ok, correct? If I am reading the information correctly

[Marcel R. Cyr]

Manufacturers instructions of the particular unit should be adhered to in proper installations.

The product specifically tested and listed for use with pellet stoves is PL vent pipe, labeled as tested to UL 641. PL vent pipe is double wall pipe; the stainless steel inner pipe that carries the exhaust products is separated from the outer wall by an air space. Pipe joints must be sealed gas tight to prevent exhaust products moving through the vent under pressure from leaking into the home. Stoves tested and listed requiring PL vent must use no substitute venting materials.

Venting materials and products that MUST NOT BE USED TO VENT PELLET APPLIANCES include:

• <LI itxtvisited="1">Dryer vent <LI itxtvisited="1">Gas appliance (Type B) vent <LI itxtvisited="1">PVC (plastic) pipe
• Single wall stove pipe (unless clearly approved by the installation manual and local codes)

Fig. 1 Pellet fireplace inserts and freestanding stoves are often vented into existing masonry and factory-built fireplace and wood stove chimneys (Fig. 1). The chimney should be inspected before installation to ensure that it is clean, mechanically sound, and meets local safety code requirements. The appliance manufacturer's installation instructions may require relining the chimney with an approved metal liner, pipe, or PL vent. Vents or grilles on the face of factory-built fireplaces which provide cooling air to the outside jacket of the fireplace must not be blocked. Cleanout access for future maintenance should be considered.

Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6












The options for venting layout fall into the following categories:

• <LI itxtvisited="1">Sidewall horizontal venting (Fig. 2)
  Invariably the least expensive venting system. Disadvantage of potential smoke spilling into the house in the event of a power outage or component failure, or house depressurization.
  <LI itxtvisited="1">Horizontal vent with backup vertical venting (see Fig. 3)
  Preferred horizontal method that avoids venting problems associated with unexpected appliance shutdown.
  <LI itxtvisited="1">Vertical venting through the ceiling and roof (Fig. 4 and 5)
  Has the advantages of keeping vent gases warm and of providing natural draft to prevent problems in an unexpected shutdown.
  <LI itxtvisited="1">Venting into existing chimney (see Fig. 1)
  Stove manufacturers provide recommendations for venting into masonry and factory-built chimneys, which may include partial or full chimney relining.
  <LI itxtvisited="1">Natural Draft
  All vents for appliances designed without mechanical exhaust fans must meet stove manufacturer's requirements for minimum draft and must terminate above the roof.
• Horizontal and vertical (Fig. 6)
  Extends from the top or back of the appliance, penetrates the wall, turns up to penetrate the eave and roof.

Besides appliance requirements, several other factors may be considered in specifying pellet venting systems. The following factors may play a role in the designation of the venting system:

• <LI itxtvisited="1">Altitude
  High altitude installations, generally higher than 2500 feet above sea level, may require special venting options to provide adequate combustion air and/or draft.
  <LI itxtvisited="1">House Pressure
  Extremely tight house construction or strong kitchen, bath, or other exhaust fans may create a negative pressure within the home that decreases venting effectiveness. May necessitate an approved outside air source.
  <LI itxtvisited="1">Windy Conditions
  Unpredictable effects of high winds or prevailing wind conditions may necessitate the addition of vertical venting extending above the roof and/or special termination caps.
• Cleanout and Maintenance
  The venting system must be designed with normal maintenance in mind.

When assembling and joining together pellet venting components, appliance manufacturer's instructions should be followed closely regarding sealing joints and seams, particularly of pressurized mechanical exhaust vents. It is imperative that they be gas tight so that they cannot leak. Proper application of an approved sealant or sealing band is typically required. Appliance manufacturer's instructions for pipe sealing which exceed vent manufacturer's instructions must take precedence.You can get a sense of what heating with pellets involves through an introduction to the principles of operation and the reasons for maintenance that you will come to understand as an experienced operator.

Hope this helps a little.

Marcel

[Charles Hellickson]

This helps a bunch. Thanks for the great info.

[George A. H. Luck]

Thanks Marcel. That is really useful information. I own two pellet stoves and love 'em!!

[Brian A. MacNeish]

From an above post:



"http://www.nevelsstoves.com/articles...llet-stove.htm

Venting your Pellet Stove

Venting your new pellet stoves is crucial for optimum operation of your stove.

To begin let's first talk about the different types of vent pipes in the market. There are five different types of vent pipe used in the heating industry.

1. Gas vent pipe, which uses aluminum for the inside wall of the chimney. The chimney itself looks very similar to Pellet Vent pipe. Read the label to make sure. Under no circumstance should gas vent pipe be used for Pellet Vent Pipe, as the inner wall will not stand up to the pellet vent exhaust and pipe will fail very rapidly.
2. Pellet Vent pipe, referred to as L-Vent pipe, can be purchased in 3 inch and 4 inch diameter sizes. The L-Vent pipe is the correct type of pipe for your pellet stove. The inner chimney is made from Stainless Steel and will last as long as your pellet stove.
3. Corn Vent pipe is usually for corn burning stoves however, it is OK to be used for the pellet stoves as well. Corn Vent also comes with a stainless steel inner chimney, and should last the life of the stove.
4. Manufactured wood stove pipe, classified as Class A pipe, usually comes in 6 inch, 7 inch, and 8 inch diameters. This type of pipe will also work with your pellet stove as it also has a stainless steel inner chimney. However, it is not necessary to be used for the pellet stove since this type of pipe is very expensive.
5. Existing masonry wood stove chimneys with clay liner are also classified as a Class A chimneys and comes in various sizes and must have a clay inner liner. This also works very well with a pellet stove. Pellet vent pipe can vent directly into Class A chimneys."

Marcel:

Either the US calls types of metal chimney/venting by different names than Canada and there is no standardization in the North American market or the writer of the above does not know metal chimneys and pellet stoves. In Canada:

(1) metal gas chimney is referred to as "B Vent"

(2) metal pellet vent pipe (ULC Standard C441) is referred to as "PL Vent"

(3) metal "L Vent" (ULC standard S609) is approved for oil heat applications

(4) Metal "Class A" chimney (ULC Standard S604) used to be approved for oil, gas and all wood installations. Due to severity of creosote chimney fires, Class A is no longer approved for wood.

(5) Around 1987/8, a more rigid standard was introduced for metal chimneys serving wood stoves/furnaces. Since it was in metric measurement, it became known as "Class M" chimney to differentiate it from Class A. The standard is actually ULC S629 or the 650 deg C (1200 deg F) standard.

(6) Zero clearance wood fireplaces and their chimney systems are tested and approved together (ULC S610), therefore, any wood approved metal chimney may not be able to be used with a fireplace as happens with wood stove/furnace installations and the ULC S629 chimney.

It isn't that simple out there so if you're an HI in a wood burning area of the country (wood/pellet burning is still increasing strongly due to oil/gas prices), get the WETT training under your belt!! Yes it is not a cheap course and you can't take it online but we have had 20-30 year experienced certified masons (who are not trained in wood heating in their cert programs) come out of the classes shaking their heads about what they were deficient on!!

[Marcel R. Cyr]

I am just providing information to help others Brian.
I do not do WETT inspections, because of the liability involved.

Here is some more information available for some.

It is important to know that each Manufacturer has their own requirements and need to be followed, some have different requirements for venting of the units and type of vent pipe could be very well different.

http://www.ventingpipe.com/helpCente...ns#brandmatter

Marcel

[Brian A. MacNeish]

Marcel:

Looks like our 2 countries have on the venting issue have again agreed to disagree and have not harmonized the types of vent required for the same appliances. When I was writing energy regulations in the 1990's, a big push was being put on to harmonize appliance efficiency test standards so that if you tested to one country's standards, it would be accepted across the border without jumping through a second set of hoops. This reduces costs to manufacturers and ultimately to consumers!!

It was quite amazing when after 9-10 years of industry/gov meetings that a gas fireplace efficiency gas standard was finally accepted/published about 2000-2001 or so. About 440 different models were tested and the results released. After hearing of 80-85% units from the manufacturers/vendors, only 4 out of the 440 or so were over 70% when independently tested. The best was 78% and the rest were low 70's!!! The bottom end showed many units under 50% with the lowest being in the mid 20% range.......never believe a vendor you don't personally know and even then be careful!!

[Marcel R. Cyr]

Well Brian, this Pl Vent seems to be available in Canada also, so I am not quite sure why you say the standards or listing requirements differ. A pellet is a pellet and a pellet stove is many designs and requirements all dictated by the designer that has met the UL 641.

Dosen't UL 641 exist in Canada? http://www.selkirkcorp.com/SuperVent/Product.aspx?id=62

Marcel

[Brian A. MacNeish]

Originally Posted by mcyr

Well Brian, this Pl Vent seems to be available in Canada also, so I am not quite sure why you say the standards or listing requirements differ. A pellet is a pellet and a pellet stove is many designs and requirements all dictated by the designer that has met the UL 641.

Dosen't UL 641 exist in Canada? http://www.selkirkcorp.com/SuperVent/Product.aspx?id=62

Marcel

That UL standard is not recognized in Canada. UL and ULC (Underwriters Laboratories Canada) are not connected and only have similar names. A lot of people think that ULC is a branch plant of UL.....not so.

That particular vent system (called PL vent by the manufacturer and not L vent) has been tested to 2 Canadian ULC standards as well as UL 641, so it is accepted in both countries for pellet equipment.

But have a look at what we used to call "Class A, All Fuel" up here but now only call "Class A". Our residential Class A is no longer approved for all wood installations, just a few "Zero Clearance" wood fireplaces.
http://www.selkirkcorp.com/supervent...ct.aspx?id=104

but in the US, it's still "All fuel" chimney:
http://www.selkirkcorp.com/supervent...ct.aspx?id=220


The Industrial Class A is approved for oil and gas only in both countries.
http://www.selkirkcorp.com/supervent/Product.aspx?id=38

Confused enough yet??

[Marcel R. Cyr]

Yep, confused, because I am not quite sure what you are saying.

Listing: Listed to ULC S609, ULC/ORD C441 and UL 641

The listing for a PL vent is the same for Ul641 as is for your ULC S609

Bottom line is, if I see a vent on a pellet stove on an Inspection, I will question it and have requested that it be inspected by a licensed professional for that installation.
To many variations on the installation due to multiple manufacturers and their dictated installation requirements.

Marcel

[Brian A. MacNeish]

Originally Posted by mcyr

Yep, confused, because I am not quite sure what you are saying.

Listing: Listed to ULC S609, ULC/ORD C441 and UL 641

The listing for a PL vent is the same for Ul641 as is for your ULC S609


Marcel

Well, yes in a way but what the actual facts are is that particular type of vent was designed, manufactured and tested to 3 different standards and met the requirements of all. So it can be sold and used on the specified pellet equipment installed in both countries.

[Michael Larson]

ULC means UL laboratory did the compliance testing to the appropriate Canadian product Standard.