The solar water heater has small pressure and small flow when taking a bath

Update Time:2017/10/9
After household solar energy is installed, what is the reason that the shower pressure is small?:
First, the vertical solar water tank and shower head is too small; second, the pipe bend too much and fine pipeline also affects the hot water pressure; third, the level of pipeline is too long, it will consume some water; recommended for use in a parallel pipeline booster pump only when bathing,
That solves the problem.