Ill dig out my ontario gas code book monday and find out, Any changes would be in the code book and im not aware of a new releases.
And to be honest DIY has no buisness installing a furnace. These are not TV's or stereo speakers. You can mess up the install of those, but it wont risk your families life or your comfort level in the dead of winter, like a messed up furnace install.
20 years ago with old standing pilots i suppose a DIY would have been ok. But todays furnaces require proper training and installation. We are getting training year round to keep us up to date with new products.
For a DIY to duplicate a properly installed furnace would require some extras:
-Carbon monoixide detector
-fish tape for wireing
-heat load for sizing
-custom sheet metal ordered or built on site
Self install could void warranty if proven to be done incorrectly.
Licenced HVAC TECH: "Without seeing your problem i can only offer suggestions, no warranty is included with my advice"