Separated Combustion using 2 pipes?

[HDRKC07]

I had a Heating and A/C guy stop by yesterday to give me a quote on finishing an install on a Beacon Morris 45K BTU garage heater. The heater is hung, thermostat wiring ran, electrical finished. Only need to run the venting and the gas connection. The HVAC guy looked at the project and the separated combustion kit which I had already purchased and said he wasn't familiar with this setup. All the garage heaters he has installed for a separated combustion system he just ran two pipes using b-vent, one for air intake and the other for exhaust. He said he has had no issues doing this. My question is can this be done and is it the same as using that kit? I know I would have two holes in my roof versus one, so that aside is this OK? Thanks

 

[bobbyjean]

well....it's ok.. some idea's that may work for you 1-just vent exhaust 2-run intake pipe in single wall ...you can terminate that in attic if you have vented soffit's or ridge vent-just put a screen over it to keep the bugs out
3-use kit you have
4-would sidewall be an option?..
what type of pipe will be used for gas line? just curious

 

[yeldogt]

Is it a concentric vent? I always use them for a wall .... they are large ... so more noticeable on a roof vs a single plumbing vent look.

I would rather have vs two single. You can also split the intake and exhaust locations for most -- intake from the side wall and through the roof for the exhaust.

The intake will require a fitting on top if through the roof.

 

[Jackfre]

Is it a concentric vent? I always use them for a wall .... they are large ... so more noticeable on a roof vs a single plumbing vent look.

I would rather have vs two single. You can also split the intake and exhaust locations for most -- intake from the side wall and through the roof for the exhaust.

The intake will require a fitting on top if through the roof.

Be careful in splitting the system in different "zones". The advantage of the two pipe is that you have sealed combustion and therefore saw-dust, etc is not gumming up the works. It is best to have the intake and exhaust in the same area as the static pressure on the exhaust is the same as that on the intake. Most gas valves are not happy with varying or imbalanced pressures. Many of the wall hung boilers are ok with it but they have negative pressure gas valves that can operate without regard to the pressure variances.

 

[yeldogt]

Be careful in splitting the system in different "zones". The advantage of the two pipe is that you have sealed combustion and therefore saw-dust, etc is not gumming up the works. It is best to have the intake and exhaust in the same area as the static pressure on the exhaust is the same as that on the intake. Most gas valves are not happy with varying or imbalanced pressures. Many of the wall hung boilers are ok with it but they have negative pressure gas valves that can operate without regard to the pressure variances.

I prefer finding a wall for a concentric. Since I mostly do historic houses ... my goal is to hide the 20th and 21st century as much as possible. The exhaust can normally be made to look like a simple vent when the wall will not work. The intake through a roof cannot.

Always follow the directions -- The german boiler allow .. not sure about others.

 

[HDRKC07]

Thanks for the replies. Going through the wall is not an option for this installation; my only exit is vertical through the roof. Just to clarify, is it OK to use two separate b vent pipes (one for air intake and one for flue exhaust) on a separate combustion setup if the intake and the exhaust are in the same area of the roof? The contractor said he would place the chimney (exhaust) on the backside of the garage roof with the air intake in the same area with the appearance similar to that of an attic vent with a screen over it to prevent birds, etc. from entering. Does this keep the static pressure the same? This contractor has a very good reputation in the area, but I'm confused and want this done safely and correctly.

 

[bobbyjean]

sounds good...should work fine....you can return the vent kit you already i have i hope?

 

[yeldogt]

Looking at the instructions -- they show it with a concentric vent through the roof. Why not just follow the instructions and use the concentric? Looks like it needs 24" above roof for the fresh air w/ the exhaust above.

The famous "we always do it that way" should not be followed unless you can see it in the directions ...

Give the company a call and ask for the technical department -- That's the best way to get the proper information .. they can e-mail you the vent information.

 

[Jackfre]

Looking at the instructions -- they show it with a concentric vent through the roof. Why not just follow the instructions and use the concentric? Looks like it needs 24" above roof for the fresh air w/ the exhaust above.

The famous "we always do it that way" should not be followed unless you can see it in the directions ...

Give the company a call and ask for the technical department -- That's the best way to get the proper information .. they can e-mail you the vent information.

We have a winner!

 

[ripperd]

intake needs to be above any potential snow depth on the roof! So "attic vent" look is a no-go.

 

[HDRKC07]

I e-mailed tech support and am waiting for their response. Contacted another company in the are and they said they would not due it because of liability reasons. The wife is just furious because she doesn't want me on the roof trying to "cut in the vent". The company I got the concentric vent kit from says it is past there time policy to take it back. Guess I'll wait to see what Beacon Morris tech support has to say and ask the original HVAC installer if he'll reconsider using what I have. If the air vent is placed higher up would that be a possibility for being able to use 2 separate pipes. Just trying to cover all my bases. Thanks

 

[yeldogt]

I still don't see what the problem is using the concentric vent -- I believe when I pulled up the directions it showed one being used. It one hole and connect up the pipes ? Done.

FYI -- the two pie set up normally needs the inlet on the roof to have a bend (fitting) so that water does not enter. Typically this is with a condensing setup where you have PVC used.

 

[yeldogt]

intake needs to be above any potential snow depth on the roof! So "attic vent" look is a no-go.

I was referring to a plumbing vent -- the 3" PVC can be covered with copper and made to look like a 3" plumbing vent when doing an historic property.

 

[ripperd]

I was referring to a plumbing vent -- the 3" PVC can be covered with copper and made to look like a 3" plumbing vent when doing an historic property.

I guess I should have quoted. I wasn't replying to you, I was replying to OP's words:

the air intake in the same area with the appearance similar to that of an attic vent with a screen over it to prevent birds, etc. from entering

 

[HDRKC07]

Thanks everyone for the input. I got a reply back from Beacon Morris tech support and said if 2 pipes were used for separated combustion it would void the manufacturers warranty. I told the HVAC installer what they said and he is ok using my concentric vent kit, but is still questioning why on the carton the heater came in there is a sticker stating Type B Vent can be used for vertical roof termination. From the instruction manual, all I can see if I'm thinking correctly is that Type B Vent can be used if doing a Category I install (exhaust vent only and drawing intake air from the space being heated); but when a separated combustion install is being done it changes it to a Category III. Is that correct? Thanks

 

[bobbyjean]

huh...now i'm confused b-vent can be used for vertical termination...... and it was allowed to be used for ever to vent horizontally as well...it isnt anymore and i have not read as to why....sealed joint system like z-flex are now required...hot air rises...always will, you can use that kit...leave a 1 inch clearance to combustibles around all penetrations,both intake and exhaust above snow line on roof.... no opening skylites in area..should be good to go

 

[HDRKC07]

I e-mailed Beacon Morris Tech support again and they said Type B-Vent can be used for vertical roof termination if not doing a separated combustion installation. At this point it is a Category I type of installation. They said the change in code requires horizontal wall or vertical roof terminations using separated combustion installation to meet Category III requirements. They said for the vertical roof termination for a separated combustion installation the exhaust has to be UL 1738 stainless vent pipe, but the outside air intake from the concentric vent box to the intake on the heater can be Type B-Vent pipe. Thanks everyone for the help.

 

[B.Holder]

Did you get the install finished and if so how?