Heater get cold on hi speed fan

When I use heater on low fan speed everything is fine, but when I put the fan speed on high, it start to blowing warm and after a few minutes completely cold. I should turn the climate control off then back on on a lower fan speed to get the heat back.
Anyone has any idea or experience about this issue?
Prius 3, 2014 Japan made.
Thanks

 

For people having the same problem, I replaced the water pump and problem solved!