doctor wrangler made a comment that they had problems with the water heater the past few weeks. he felt that that was the problem, due to the carbon monoxide detector going off. diane steube or remembers her husband worried about the heater to. saying the exhaust on the roof was not place there directly. could that have caused the backup in the house? and mark said he was scared of it. it sounds like mark wrangler happen and kathy just happened to be upstairs that night. mark was downstairs. it seemed like a sad, but explainable accident. but as it turns out, it was not so simple. coming up. growing suspicions that something was missing. do we walked around the house, we looked at the water heater, we looked at the other appliances and could not find the source for carbon monoxide.