I have 3 units of Rubine water heater (built-in ac pump) bought on January. 1 in the ground floor bathroom and the other 2 in the first floor bathrooms.
They were all running fine until the water disruption started in Selangor. One of the 1st floor unit doesn't function well anymore. When I turn it On and use, the pump sounds very weak and it dies off after a while leaving the water pressure extremely slow. But funnily, the water pressure is like normal from the taps in the same bathroom.
The other 2 units are working fine. Is the problem with my piping or water heater?

Anyone can guide?