I had been a member of Reliance's maintenance program and booked an appointment for my furnace to be looked at prior to the cold weather starting.
The technician was very flippant upon seeing the age of my furnace, suggesting it may have some cracks in the heat exchanger given the age. He spent time pulling apart the furnace then said it appeared to be leaking exhaust and therefore said he was required to red tag it (read: turn it off completely and register it as faulty with Enbridge). The furnace was left torn apart - the fan and various wires laying beside the unit.
After some online research, I decided to get a second opinion - the 2nd company came to my home and explained that a CO monitor would be used to determine whether there was indeed a leak -- anything above the 100 unit acceptable threshold being considered dangerous. Testing the furnace with the CO monitor in 5 locations, the readings averaged well within the allowable range (in fact, the readings were considered extremely low, measuring 13/100). As a result of this company's thorough testing, the red tag was lifted.
I called Reliance to explain the situation and was promised some remedy from a number of different individuals - having been escalated through customer support, area managers, etc. but was never provided any such remedy.
