B-vent pictures anyone?

[FastEddieG]

Hey guys,

I was toying with the idea of doing my own garage furnace again. In my old house, I put in a ventless wall mount. The gas pipe was close by in the basement and easy to tap into, and there were no vents to deal with. It was a confidence builder. However, in this house, the gas pipe is 30' away and would be difficult for me to tap into and run due to lack of unions in the vicinity. Plus, I am going with a vented furnace this time so in order to vent horizontally, it will go through brick. Not zesty and makes me uncomfortable.

I don't have the experience or skill for either of those, and it would require lots of pipe cutting and threading which I don't have the tools for, so I am hiring one of my brother's friends to do it. Union guy looking for side work because of this crappy economy. $1325 for the 45k furnace, supplies and installation. (a little less than half for labor). After thinking about it, I decided it's well worth it to me to have it done so quickly and done right.

So, did any of you horizontally vent your garage furnace? Have any pics you can share of how it looks outside of the building?

Thanks in advance,
-Ed

 

[dipper]

Mr. heater 45kbtu vented horizontally to vinyl siding.

 

[FXR]

Hey Dipper, what is the tan metal plate? Is it metal roofing mounted to stand offs?

 

[FastEddieG]

Thanks Dipper, that helped! My furnace is being installed as I type this. I'll take pics of the finished work and horizontal venting soon.
-Ed

 

[dipper]

Hey Dipper, what is the tan metal plate? Is it metal roofing mounted to stand offs?

It's actually a section of vinyl fencing panel that I had. It was white but I spray painted it tan to be a closer match to the siding. It is screwed into the osb with some stainless screws. It worked pretty well and allows the outside part of the wall thimble to lay flat instead of against the stepped siding.

 

[FXR]

Thanks for the info!

 

[ripsnortMN]

Mr. heater 45kbtu vented horizontally to vinyl siding.

In my Modine hotdawg instructions it stated that you need at least 12" of b vent coming out of the exterior and then the rain cap. The instructions emphasized there had to be 12" minimum. Not sure if that was for the mr heater too.

 

[dipper]

that is about 12", it may be a little short, but i'm not worried about it.

 

[Funvtec]

I'm going to be doing an install this week almost identical. The one question I can't seem to answer is. How does rain water stay out of the rain cap? My heater instructions tell me I need to pitch the b vent toward the heater. Meaning any water that gets into the cap will drain directly into my heater. I've looked at a vent at Home Depot and it looked to me like water will get right in. Am I missing something?

 

[dfiler2]

That is a rain cap and should be terminated vertically, a B vent pipe cannot be terminated horizontally. According to manufacturers, all B vent pipes must terminate vertically with a rain cap in place in order to vent properly. It is worth noting, however, that if a category 1 appliance is being vented it may be acceptable to vent it horizontally, but only with a gas exhaust fan properly mounted to pull out the gas from the flue. The fan must be mounted on the exterior wall. Under no other circumstances may a B vent pipe terminate horizontally, though. An appliance that is approved to vent horizontally is most often not compatible with the use of a B vent pipe.

There are horizontal termination caps that would keep rain out, but not for B vent.

 

[Funvtec]

Here are my install instructions. The vent kit I can purchase from the manufacturer would give me a normal rain cap to use horizontally. And your telling me that a rain cap will not mount to b-vent. Only single wall vent pipe?

 

[tp-otus]

In Funvtec picture that is exactly how my b-vent unit was installed by my propane dealer except sloping down. 4ft total. They are telling me this is ok. What gives, are they wrong or are they correct, confused?

 

[tp-otus]

Seeing my post I should say 4ft total length for the pipe not 4ft slope, sorry about that

 

[Jackfre]

I represented Dura-vent and Selkirk over a 20 yrs span and agree with Dilfer2. B-vent is approved for a vertical termination only. That said, since the late 90's when I left those companies, I have seen it installed in many of these side wall installs as shown in your pics. B-vent is a negative pressure device. Given that the units get approved like this I can only surmise that the manuf of the appliance have been able to get it approved for their appliances as a "system". Is the rating plate for your furnace listed as a Category I or III? For a short run like yours, I would not install the vent pipe grading up and out using the standard B-vent cap as you are potentially turning your vent into a rain water leader.

That is one of the nicest cleanest vent installs I have seen.

 

[PT Doc]

For the horizontal installs that might seem to not be to manufacturer specs, can a 90 degree elbow be mounted on the outside of the house with a short vertical run terminated with a rain cap?

 

[dfiler2]

Here are my install instructions. The vent kit I can purchase from the manufacturer would give me a normal rain cap to use horizontally. And your telling me that a rain cap will not mount to b-vent. Only single wall vent pipe?

I would follow the manufacturers instructions. I will do a little more checking on it with a couple of engineers who may be able to shed some light on this. I have been told for years that B vent can not be terminated horizontally. The one thing that confuses me is that the manufacturer would show what appears to be a vertical termination rain cap, which will not keep rain out. If you are using B vent then yes a B vent rain cap would fit it, it just won't keep rain out.

 

[Mike007]

That is a rain cap and should be terminated vertically, a B vent pipe cannot be terminated horizontally. According to manufacturers, all B vent pipes must terminate vertically with a rain cap in place in order to vent properly. It is worth noting, however, that if a category 1 appliance is being vented it may be acceptable to vent it horizontally, but only with a gas exhaust fan properly mounted to pull out the gas from the flue. The fan must be mounted on the exterior wall. Under no other circumstances may a B vent pipe terminate horizontally, though. An appliance that is approved to vent horizontally is most often not compatible with the use of a B vent pipe.

There are horizontal termination caps that would keep rain out, but not for B vent.

This may be a surprise to you, as stupid as is looks, the manufactures allow category I equipment to be vented horizontally with B vent. I personally think it's dumb but it is what it is. This is accomplished with a simple statement on the equipment or installation manual stating something like: "This appliance is category I when vented horizontally". Since it's category I when horizontally vented you can use any category I vent system which includes B vent. And it will typically pass pass inspection. I believe some of the manufactures are getting away from this and now require a category III vent system.

 

[Funvtec]

I would follow the manufacturers instructions. I will do a little more checking on it with a couple of engineers who may be able to shed some light on this. I have been told for years that B vent can not be terminated horizontally. The one thing that confuses me is that the manufacturer would show what appears to be a vertical termination rain cap, which will not keep rain out. If you are using B vent then yes a B vent rain cap would fit it, it just won't keep rain out.

I appreciate all the answers and effort, every time I search for answers I end up coming across this site and this is why

 

[Scott r c]

I have installed a few horizontally, and have seen countless others done by other contractors. No problems yet.

 

[CKS1955]

The heater I just installed for horizontal venting required Class III ( AL 29-4C stainless steel, certified for category I, II, III & IV). I have attached a picture of the instructions manual.

Jay

 

[toyotadriver]

I installed an 80k btu Mr. Heater. Vented it out the side wall with B vent pipe. Works great. Also pitched the horizontal portion slightly down toward the outside just in case some moisture gets in or condenses in the pipe (unlikely) it will run out and not back into the heater.

YMMV

 

[Jackfre]

I know the owner and sales mgr at Mr Heater real well. I'll see them at a trade show the end of Jan in Chicago and discuss this with them. As well, I'll speak with a couple of the B-vent manuf I worked with and see how their engineers view this. I'll report back in early Feb.

 

[rob in nh]

i just installed my heater and the exhaust doesn't extend outside enough so i'll get another piece to extend it. could someone tell me why it has to be 12 inches on the outside?

 

[laser3kw]

I am curious looking at the picture posted previous. Is there any concern with the heater vent pipe pictured terminating at or near the soffit ? Maybe not the case in the picture, but if the soffit is used for attic ventilation would there be a possibility of the exhaust recirculating back through the soffit? Or are there "codes" that dictate how close and relative placement?

 

[Mike007]

i just installed my heater and the exhaust doesn't extend outside enough so i'll get another piece to extend it. could someone tell me why it has to be 12 inches on the outside?

I would guess if it's too close the concern is in cold weather the flue gases could condense on the side of the structure staining it.

 

[Funvtec]

Found a cap that was made for a pellet stove. Also rated for gas. I just used that instead. Designed for horizontal applications.

 

[Funvtec]

Still needs j channel. But you get the point.