Mr Heater horizontal vent problem? Help!

[perkin50]

I just finished mounting and installing the vent on my Mr Heat Big Maxx. Unfortunatly, after the install I discovered that venting the heater under the soffit is a no no. As you can see from the pics the vent comes out below the soffit. I am considering redoing it and either running it through the roof or out the gable end. Any ideas?

 

[GTO]

Can't you just extend the end of the vent pipe out beyond the soffit ?
Good Luck

 

[billyjk7]

I would just throw a 90 on it and take it about a foot above the soffit

 

[perkin50]

I like extending it out past the soffit. It will not meet code as code states that the exhaust vent should be a minimum of 4' fom the soffit.

 

[scooter1979]

When iI installed mine i also found out they have to be a predetermined distance from any fresh air intake. In your case the soffit. Pretty sure 2 feet from peak of roof and 6 ft from windows and make up air vents

 

[perkin50]

I will probably extend it another 12" out from where it is now. The only other alternative is to redo it out the roof or out the gable end. Too much work at this point.

 

[dave67fd]

Do you have a soffit on the opposite wall? You could rotate the heater and come out the other wall. Of course not sure how you have the gas/elec configured and might have to alter. although it doesn't look like you have that in yet or is it just the pic?

Sometimes locating the heater where you really want it doesn't always work out with hooking up the venting and utilities. You really should have read the manual and researched all the issues/codes over and over again. Iv'e spent quite a bit of time reviewing all the avenues to avoid hassles like this. It can be a bit frustrating. Im sure you will figure it out.

Send pictures when you get the gas/elec hooked up as well as your fix for the venting.

Good luck.

 

[T mac]

I hate to say it because you already have installed but the best thing you could do is revent it going out through the roof it is going to look better,vent better and best of all it will meet code and you will have all of your clearences to everything that you should have.

 

[LARSOFVT]

Who told you it was a no no? I have diagrams in the Modine book that show that configuration provided certain spacing requirements are met. I am discussing the soffit option with my own gas installer.

I just finished mounting and installing the vent on my Mr Heat Big Maxx. Unfortunatly, after the install I discovered that venting the heater under the soffit is a no no. As you can see from the pics the vent comes out below the soffit. I am considering redoing it and either running it through the roof or out the gable end. Any ideas?

 

[T mac]

Your gas installer is going to tell you it is a no no also.In the code i believe they want a minium of 4 ft clearence for a vented soffit.You can vent it out the way he has it by extending out farther and up to get your clearences but it is going to look sore. Your best bet is going out through the roof its the right way to do it.Not the only way but the best way.

 

[perkin50]

Sure, going out the roof is probably the best option. However, at this point the vent is already ran and I have a big hole in my wall and really do not want to cut another one.

 

[T mac]

Well it sounds to me like you have one available option then extend the vent out and up to meet your local code requirments then. Good luck with your project.

 

[brewchief]

Sure, going out the roof is probably the best option. However, at this point the vent is already ran and I have a big hole in my wall and really do not want to cut another one.

Looks like reading the instructions first would have saved you some grief, might as well cobble it up now instead of doing it right

 

[darkk]

I would see if I could cover the existing pipe with something double insulated and extend it and 90 deg elbow it up past the roof. You already cut ahole in the tin sidewall. be a shame to leave a patch over that...

 

[perkin50]

I kicked it around and as many of you said the right way is to goe out the top. So that is what I am going to do. I will post some pics.

 

[Speed-Racer]

I would just extend the pipe, that will be the easiest fix.

Also, All horizontal category III vents must be terminated with a Gary Steel 1092 or Breidert Type L style vent cap. This is per the mfg instructions. I finally purchased one of these caps, lots of differences from the standard vent caps. I was glad it was not just marketing hype. This style cap has baffles that keep the wind from blowing out the flame. You may want to look into purchase one of these caps, they can be a little expensive.

 

[brewchief]

I would just extend the pipe, that will be the easiest fix.

Also, All horizontal category III vents must be terminated with a Gary Steel 1092 or Breidert Type L style vent cap. This is per the mfg instructions. I finally purchased one of these caps, lots of differences from the standard vent caps. I was glad it was not just marketing hype. This style cap has baffles that keep the wind from blowing out the flame. You may want to look into purchase one of these caps, they can be a little expensive.

Extending the pipe creates more problems, he needs to be at least 4' from the soffit vent, this would require either having a pipe sticking out at least 5' from the wall or turning and going up. According to the Mr heater manual I found online the max vent length for horizontal is 5' plus one elbow in a residential application. Turning and going up may make it considered a vertical vent but with the amount of exposed B vent you would have condensation in the vent pipe is likely.

Mr heater rates the big maxx as a cat 1 vent in a residential horizontal application.

The Mr heater manual makes no mention of any specific cap, the heaters I've seen that do specify that type of cap also say "or equivalent", last time I checked B vent is only listed for use with parts made for it, you cannot mix brands, most manufacturers do offer a "high wind" cap that is what is being referred to as far as I can tell.

Does the roof the vent needs to go out have shingles or is it steel? They make a nice rubber boot flashing for steel roofs, it has a lead flange that will conform to the ribs in the roof nicely.

 

[perkin50]

Well the pipe is now routed out the top.

 

[jumbo61]

Looks good. BTW, I see you used osb on the ceiling and walls(?). Are you happy with it? I'm contemplating using osb in mine. Thanks.

 

[perkin50]

Looks good. BTW, I see you used osb on the ceiling and walls(?). Are you happy with it? I'm contemplating using osb in mine. Thanks.

I researched it quite a bit. In the end, the cost, durability, and look was hard to beat. I am very happy with my choice.

 

[brewchief]

Looks good, before you insulate add a shield around the pipe to keep the insulation at least 1" away form the B-vent.

Is the second piece of pipe on the outside single wall or double? The pic sorta makes it look like single, if it's single swap it to double before cold weather hits or you will have condensation issues and the pipe will not last long, if it's double your good to go and ready for winter.

 

[perkin50]

Looks good, before you insulate add a shield around the pipe to keep the insulation at least 1" away form the B-vent.

Is the second piece of pipe on the outside single wall or double? The pic sorta makes it look like single, if it's single swap it to double before cold weather hits or you will have condensation issues and the pipe will not last long, if it's double your good to go and ready for winter.

Thanks. The pipe on the outside is single. I will look into getting a double pipe.

 

[T mac]

You definately made the right choice and it looks good and is going to work properly.Nice work!

 

[LARSOFVT]

Nice install..

Can we discuss why the under soffit venting is not allowed?

I have attached a scan of the Modine Hot Dawg manual that shows venting under a soffit.

 

[dave67fd]

Who said it wasn't allowed?

It is allowed if proper codes are followed and the correct materials are used. In this instance they were not and had to be readdressed. National gas codes and NFPA codes need to be followed but local/state codes take priority. The local/state codes usually follow these and may adjust as necessary.

In my town i am required to obtain a permit from the local fire dept. You are required to follow NFPA58 and when the installation is complete, they will inspect.

The literature that is sent with the heaters are general guidlines to be used as reference or to be followed in the absence of any local codes.

Although the Modine and the Big Maxx are quite similar their documentation varies quite a bit when it comes to installation. If you read both completely it would probably confuse most people because of their "Descrepencies".

Installation codes can vary extensively depending on many factors. Is the installation residential or commercial? Is it located in a dwelling, attached or detached? etc.. etc..just to name a few.

 

[LARSOFVT]

Who said it wasn't allowed?

I asked the same question in post #9 but got no response.

 

[scooter1979]

I am pretty sure you need to install a fire stop in ceiling reguardless of double or single wall thickness. I just installed one last fall and mine to was a PIA.

 

[brewchief]

The biggest problem with the under soffit venting in this case was the vented soffit, it would be considered an opening into the build so clearances to it needed to be followed, getting the proper clearance and staying within the guidelines in the manual would not have been possible. Remember that one of the products of combustion is water, do you think that a ton of water vapor drifting up into a vented soffit would be a good idea?

With the current code I have been told that even a bath vent vented out the soffit needs 4' of unvented soffit on each to pass inspection, I haven't run into that since we got out of the new construction game just before they switched to that codebook here.

 

[Relie]

You'll feel a lot safer with the double wall pipe all the way out. That's the exact same way that I did mine and feel a lot safer. (I started with single wall pipe and changed it right away.)

Dave

 

[perkin50]

You'll feel a lot safer with the double wall pipe all the way out. That's the exact same way that I did mine and feel a lot safer. (I started with single wall pipe and changed it right away.)

Dave

Hey Dave, I was not aware that it needed to be double outside. Brewchief actually caught it and let me know I would have issues. But it does make sense that if the hot exhaust is going out a cold exterior pipe then the moisture from the exhaust can condensate inside the pipe and cause issues

I also wanted double through my ceiling and roof to minimize heat transfer and prevent a possible fire.

I just removed the three foot section of double with the two foot single extension and replaced it with one five foot foot section of double pipe.

 

[Relie]

I also wanted double through my ceiling and roof to minimize heat transfer and prevent a possible fire.

This is the main reason I changed mine and the cost wasn't that much more. Good luck with your system. It is sure nice to work on the cars in a warm garage in the middle of the winter.

Dave

 

[BD1]

Sure, going out the roof is probably the best option. However, at this point the vent is already ran and I have a big hole in my wall and really do not want to cut another one.

Hi, leave the opening and use it for a exhaust fan >