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Training info. request-vent inducer/ boosters


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I'm looking for information regarding installation requirements for in-line inducers and boosters for gas fired appliance vents.

So far, I've found that Tjernland manufactures both inducers and boosters for this purpose.. Are there other well known manufacturers of inducers and boosters intended for this use.

What are your thoughts regarding this recommendation for single wall vent? http://www.tjernlund.com/Tjernlund_8504003.pdf

http://www.tjernlund.com/Tjernlund_S...it_8500594.pdf

So far, the only vent type I've found that is actually rated/ listed for Cat 1,2,3&4 venting is the Selkirk Saf-T vent: Selkirk: Saf-T Vent EZ Seal

Under Tjernlands FAQ section, they indicate that their in-line draft inducer is allowed to be used with B vent. I contacted Selkirk and Dura-Vent to get their take, and only received a response from one of them, which was not helpful. All they said was that B vent was for vertical venting only, and left it at that. My concern is that in- line inducers still create positive pressure inside of the B vent for several feet.

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Field Controls also manufactures booster fans.

You're discussing a booster fan that is intended to be installed on a vent connector that vents a Cat 1 appliance to a natural draft chimney or vent.

Booster fan instructions usually state that all joints must be sealed and the fan must be installed as close to the chimney/vertical vent as possible.

Unless there's a major problem with the vertical B-vent (undersized, reduced, too short or blockage), I don't think there would be an issue with the slight positive pressure.

Rather than accepting a booster fan, I try to find the problem that caused the improper venting. It's usually a chimney/vertical vent or the vent connector installation error or inadequate combustion air.

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Thanks for the info. Bill.

I probably should have started 2 separate posts in order to simplify things. We rarely see either installation in these parts. These have come up recently, and we're trying to set up a training class for service technicians. It will be pretty basic, such as when a barometric damper is required, inter-lock requirements, allowable venting types for horizontal vs. vertical venting, etc.

Booster fan instructions usually state that all joints must be sealed and the fan must be installed as close to the chimney/vertical vent as possible.

I guess I'd better get my terminology straight. Tjernland considers the in-line inducer an option for B vent installations, and is for vertical venting applications. They don't require any type of sealed venting system for this, as per their FAQ section. This is the device I'm looking at: Inducer Installation We see these used where there is a long horizontal run of single wall or B vent, such as in an attic or crawlspace. There is typically no actual vent connector, just a single run of either A or B vent from the appliance to the roof line. There are no combustion air issues typically (we check).

The "booster fan" I was talking about, is actually a sidewall venting product/ power venter seen here: Sidewall vent

Tjernland calls for type B vent for this unit Instructions. If I'm reading this right, I'm confused due to the fact that type B vent is supposed to be for vertical vent installations only. Also, depending on where I pull up installation instructions, and for what model, I get varying info as to whether B vent is needed, or whether sealed single wall venting is necessary.

It seems like the Selkirk Saf T Vent would be a better option, as it's approved for cat. 1,2,3&4 venting.

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Rather than accepting a booster fan, I try to find the problem that caused the improper venting. It's usually a chimney/vertical vent or the vent connector installation error or inadequate combustion air.

Our service technicians don't actually do any installations, just inspections of new and existing equipment. It's their job to determine whether the installation is safe and functional, not to determine whether it's the best installation option. If equipment is found to be improperly installed or unsafe, they have a few options depending on the severity of the problem:

1)They can just leave a form indicating there are installation issues, but leave the equipment on.

2)They can shut the equipment off and hang a red tag indicating the equipment is unsafe to use until repaired.

3)They can disconnect and cap the gas line and hang a red tag. Disconnecting the line is reserved for major issues.

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The codes say all positive vent pressure venting must be listed such as AL29-4C ss or plastic glued venting per mfr. such as PVC. B-vent is not rated for positive vent pressure. You can use a wall terminal power vent with a pressure proving switch wired into the primary control but other than that none of that Tj stuff meets the code where it blows it out. Same with single walled vent connector--negative pressure only. Gooping joints was tried and UL rejected it for maintaining the UL 441 listing on B-vent.

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No law preventing anyone from selling things just because the end use does not comply with codes. Every unit heater in the country vented with single walled pipe is illegal but you see them in every warehouse and auto repair garage. Nobody cares apparently. We have the choice of being apathetic or walking the walk. We can't force our customers to do anything but simply provide them with information to form an opinion upon which to determine a course of action. Lots of products fall into this category.Then again, there are zillions of products for which there is no clear code or standard directly relating to them. That's where we have to divine the intent of the code and stds. That's where an AHJ must rule using test reports, listings, white papers, etc. Let's say an AHJ signs off on using a Tj power vent per the mfrs. listed instructions. Later, there is an incident resulting in personal injury, fire or other damages. Is the AHJ liable? Nope. He has a get out of jail free card. There is no guarantee the device will work or is "safe" whatever that word means. In this case, it just means an AHJ went against the codes and stds. to approve a device. It's all a game. We and out clients are the ones having to live in the buildings with these things.

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No law preventing anyone from selling things just because the end use does not comply with codes. .

If the end user follows the manufacturers instructions to the letter, and something happens, I guess the manufacturer had better have some good lawyers.

Every unit heater in the country vented with single walled pipe is illegal but you see them in every warehouse and auto repair garage

Sure do. Seeing as how I am inspecting these things several days a week, i'd better find out why single wall vent pipe isn't allowed for use with unit heaters. Do you have a source or info. you can send me? Our building code: Mechanical Code appears to indicate that single walled vent pipe is allowed. See C503.7

Unit heater manufacturers specifically call for single walled venting for horizontal runs Example Will you point me to your source that indicates single walled venting is never allowed for horizontal venting?

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On unit heaters, mfrs. say ok to use single walled but these vent under positive pressure. Can't use unlisted single walled pipe even if joints gooped. Done. Can't use B-vent under positive vent pressure, even if joints gooped. Done.

He's asking for the source of your "Can't...Done". I'd really like to know as well.
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I inspect many older natural draft unit heaters, so as of right now I still believe that unlisted single walled pipe is acceptable for that application. I started to worry I was missing something obvious on my inspections when you said "every" unit heater vented with single wall is illegal.

As of right now, I'm only aware of a couple of listed single walled vents (Z-Flex for one) that are listed for cat. 3 venting, but I'm still digging.

Bill,

I believe the proper code citation preventing unlisted single wall vent from being used with a mechanical draft system is C503.3.3 (1), at least for OR's mechanical code here.

But, when I read table C503.4, it indicates type 3 venting systems must be installed in accordance with the appliance manufacturers installation instructions. These instructions often specify unlisted single wall vent pipe with 3 screws per connection, and a double tape wrap (such as the Modine unit heater I linked to), with a single section of B vent at a wall termination.

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