There's no problem with a one-pipe system, but the rules for venting are different. I've read dozens, maybe hundreds of high-efficiency furnace installation manuals. Every single one of them had ...

Skipping the manufacturer's instructions during installation may result in a furnace that fails within six months or less. For example, heat exchangers can crack from improper venting, and gas valves ...

Residential gas-fired equipment is changing and so are the related codes. As efficiencies and energy factors creep up — whether organically or because of regulation — the installation processes and ...