Hello All… I am trying to upload a pic from today that had a water heater vent pipe that was behind a furnace vent pipe. It was my understanding that the smaller btu gas fired appliance should be in front of the larger for backdrafting issues…?? If I could compress the pic…Arg…I would show you! This is correct is is not??
PS … How the #@$$% do you compress a pic to below 100kb for this message board…?
Thanks,
Chris
A smaller flue pipe from a natural draft water heater ideally would be best installed on the chimney ( breach) above a larger FAU natural draft flue pipe…
Yet as we all know each and every installation is different due to all the variables the installer encounters like space , current installations, different appliances, location , other pipes, walls…and so on.
Best practice is what the MFG installation instructions recommend.
I highly recommend this web (Gas) Association of Appliance and Equipment Manufacturers. site:
www.gamanet.org/gama/inforesources.nsf/vAllDocs/Safety?OpenDocument
Go to venting done right for a fantastic video on proper venting methods.
These guys make the appliances so they are key in understanding what happens. 
Chris try this.
Chris, if you use XP dowmload this. http://download.microsoft.com/download/whistler/Install/2/WXP/EN-US/ImageResizerPowertoySetup.exeIt free from microsoft. After install you can right click on any photo file or folder and have the option to resize the photos.
Thanks Mike, Bruce and Patrick…I will try to upload the pic now.
Chris