Our Kenmore 2013 gas water heater was making a hissing sound. I found out when I turned off the water to the water heater, it stopped and the water meter stopped turning. We did not use any hot water so it was not just refilling due to usage. It also runs constantly.. We also found the water was not as hot. I read other posts that there may be a leak under the slab, which we are on. I don't think this is the case since no pipes go under the slab except the separate hot baseboard system, which is separate. The hot water heater has a warranty but if the problem is something else, I would have to pay. If a pipe was leaking, I would think I would see it leaking somewhere. Tomorrow I am going into the attic where I possibly can see some of the pipes. Any suggestions?

Hello, I had the gas company over to check a pronounced gas smell in the garage. They could not locate the source within the garage or the adjacent HVAC room. But on the outside they did identify a significant reading coming out of the furnace exhaust pipe even if the furnace was off. (Believe the reading corresponded to 1/10 of a percent). I've shut off the gas supply to the furnace and will be leaving the HVAC off till professional help arrives. But in the meantime I wanted to ask whether a faulty gas control valve is the likely culprit under similar situations? Perhaps there are other possibilities to rule out first? Thanks for any insights!