I am using a HOT-1-1 drinking water instant heater for almost 2 years (drinking water is coming out from my Reverse Osmosis filter system with a big storage tank to this heater) . These days, the hot water coming out seems with a lot of air bubbles that splash hot water and hit my hand. I have replaced the intake 1/4" with new pipe. I have cleaned up the faucet and any possible areas of it. All these works cannot made any improvement. But the other separate cool water faucet from the same water source is working fine. I cannot think up any possible work that can improvement the heated water flow. Need expert advice to solve this problem. Thank you.