Hi again guys i tried several times to get a co2 sniffer from fire dept and still no luck.Ok i have a enviro ef3 freestanding model about 4yrs old i ran a pipe into another room on to the air intake in the back and the smell blowing aout of the heat tubes is gone now.But there is still a leak i cant find yet at the back of the stove- i tried turning lights ou on start up with flas light and nodda that i can see anyway.I replace the exaust gasket i re siliconed lots and even doubled taped other joints on pipes.Is there something i can do to pinpoint the leak? thanks again