1. Cold water inlet by sub-tank:

- Sub-tank fills the system mechanically by the float.
- The cold storage tank should be higher than the solar water heater system.
- Air vent should be installed on the sub-tank to release the vapor in summer.
The advantages:
1- Lower pressure on the system.
2- Prevent any heat loss since it slowly refill water.

2. Hot water inlet by electric valve:

There are two kinds of electric valve (low pressure and high pressure).
- The low pressure valve is installed when the cold storage tank is higher than the system.
- The high pressure valve is installed when the system is directly connected with the main drinking water.
- Hot water outlet should be installed on the bottom storage tank opposite to valve.
The advantages:
1- Providing complete control on the solar water heater.
2- Guarantee controlling the water quantity in the storage tank of the system.
3- Full benefit of using hot water solar water heater storage tank.

3. Water inlet by pump:

The pump works in the same way as the electric valve work.
The advantages:
1- Providing cold water without the need to raise the storage tank.
2- Full control on the system.
3- Guarantee controlling the water quantity in the storage tank of the system.
4- Full benefit of using hot water.

The water should be provided from one side and pulled from the opposite side, and flexible connections should be used in input and output of the system.