Water Heater Installation Guide 

Have u found out how to uninstall it because i wanted to uninstall it as well

Same as my one

I had the same problem and asked Panasonic to check. The technician told this is cause by high water pressure that damage the water valve in the unit itself. They replace the part because it still under warranty and I added a water valve before water entering the unit to control the water pressure.

air keluar pelahan tu semasa pertama kali install dan guna atau baru baru aje dah perlahan? Ada mungkin pump atau filter sumbat?

Not so hard to press. I prefer auto ON/OFF type when water is supplied and cut-off to heater.