EnerRoyal is no longer in business they were known as Enerroyal Technology Corporation and they were located in Syracuse, NY and partnered with Agway Energy which is now owned by Suburban who changed their name to Suburban Energy after the acquisition of Agway.
I know for a while if a furnace had to be replaced. Agway would honor the warranty, by replacing the furnace with a brand of their choice. Iím not sure how Suburban might be handling that now.
Your friend in the industry, Alan R. Mercurio