Mine did the same thing last year, burped once every hour or so. Couldn't find a leak,so I thought I was good to go as it likely was a leak-back through the pump. Well, while winterizing this fall, I noticed the floor was all wet between the wall and the water heater. The only way I found it was, the water had compromised the floor under the water heater. I'm ripping out the water heater, flooring, and OSB sheeting and maybe replacing the floor joices this spring.
Check every inch of water piping to be absolutely sure there are no leaks. I did, with the exception of the 2 ft that runs behind the H2O Heater and thats where the leak is.
