The 2 instant water heater for shower room at home turned 10 years old recently. My wife has been complaining about the low water pressure coming out from them and asking me to replace them for a while now. I was googling on suitable replacement for them but couldn't really find the time to compare and finalized on a good one. After the Circuit Breaker (CB) kicking in last week, I finally get the time to clear off some of my "household backlog". In fact I have so much time on hand that instead of trying to find a suitable instant water heater online, I disassemble my current one to see what's causing the water pressure to be so much lower than I first bought it 10 years ago. After some loosening of screws and detective work, I found that there is a flow control valve in the instant heater...