PANASONIC heaters are like that one.
Do not bother to change any parts. Expensive.
Either:
1. Install an additional external valve on the inlet pipe.
2. Replace with new water heater, 10 years already paid back.

my downstair panasonic heater oso same problem after 1yr

nvr bothered to find out y cos jes off at my own wall angle valve oni

if change new 1 get those with RCCB, not ELCB

I'm replying to 4 yo thread. Thank God I managed to rectify the problem of water can't stop flowing. I suspected something wrong with the inlet body. Maybe the rubber washer need to be replaced or something.

The culprit was few grain of sands that got stuck in the inlet body prevented the valve from fully close.

my unit just started to have the problem these few weeks, is it easy to replace?