By Claire Bates PUBLISHED: 06:10 EST, 23 November 2012 | UPDATED: 10:12 EST, 23 November 2012 Heather Weir and boyfriend Jamie Ness could not understand why their normally active golden labrador wanted to sleep all day A couple say they owe their lives to their pet labrador after his strange behaviour prompted them to call in engineers. Heather Weir and Stoke City footballer Jamie Ness could not understand why their normally active dog Alfie suddenly wanted to sleep all day. Investigations eventually revealed that the couple's Aga cooker was leaking lethal carbon monoxide gas that could have killed them. One-year-old Alfie was sleepy because he was being slowly poisoned by the colourless, odourless gas.
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Heather noticed her dog was sleeping all day, had stopped playing with his toys and was very lethargic
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Engineer discovered carbon monoxide leak was slowly poisoning labrador and could have killed couple
After noticing a strange smell, @placeholder had the stove checked and discovered it had been serviced and passed that month.