We have 2 john woods 30 gal hot water heaters each with beckett oil burners and 5 ft. direct vent flues going directly outside. These units are connected on the hot water side in parallel providing hot water to 3 magicaire hot air heating units and household hot water.One unit has given off an odour similar to flue gas since it was installed. Since the other unit provided adequate heat it was used solely for the last year. It now is giving off the same odour.
Several qualified service men have changed filters and nozzles and have fine tuned the air intake. Both units burn cleanly. The service men have sealed with silicone both gaskets where the burner joins the pot. They have also sealed around the edges of the flexible exhaust pipe where it comes out of the tank.
A carbon monoxide meter in the master bedroom (which is directly above the furnace room and which has the worst smell) shows 0, it has a memory of highest readings which show 0. We are concerned about health and have moved out of our master bedroom. Any suggestions.