Steam Shower Generator making strange thumping sound

[bbari]

I bought a house several years ago and the previous owner had a steam shower installed. It has worked perfectly for years and still does work as it should. But it has developed a knocking noise. It almost sounds like water drip but its not, its like air or something knocking in the steam generator box. And of course this box is built into the wall behind the shower where 1 access point is a vent sized 1ftx1ft, or I can remove a cabinet built into the bathroom beside the box. The cabinet is on wheels, but I have to break the seam of the cabinet/wall and remove the baseboard to get it out.

The sound comes and goes. I'm trying to figure out if it's worth tearing that all out to get to it, or if its something that needs immediate attention.

 

[Twowaxhack]

What you describe sounds like the pipe expanding and rubbing on something. Or the whole unit expanding as it heats up.

 

[bbari]

What you describe sounds like the pipe expanding and rubbing on something. Or the whole unit expanding as it heats up.

Would this start up as something new? In the 3.5 years we've lived in the house it's never made noise, but for the last 4 months it makes that knocking sound. And of course it happens at night so it sounds extra loud. Then it will just go away. We use it on a regular basis and it doesnt seem to matter if we use it or not, the sound will come and go on its own.

 

[Twowaxhack]

It seems if you’re not using it that it wouldn’t be making any noise.

I have no clue.