It's a wide-spread Florida house, so all on one floor and the master bathroom is on the opposite side of the house from the heater which is in the garage. It takes about a minute to actually get hot water.
A few days after the heater was installed, I noticed that there was some air in the hot water line in the shower, just about at the time that the hot water finally arrives. It's really only noticable in the morning, but it's getting worse, not better. I figured that maybe it was air trapped in the system, but it's been about a month and I would guess that the air should be out by now.
I tried the hot water in the bathroom located near the heater and it happens there as well. So I suspect the hot water heater is somehow letting air into the system. I have no idea how that could be since water is sort of pressurized, but I don't know what else it can be.
The plumber says that it can't be from the hot water heater.
Can someone suggest how it could be the hot water heater, or what I can do to find out how air is being introduced? Should I just try bleeding the whole house by leaving all the faucets open for 10 minutes or so?