As water heats it expands displacing the cooler and less dense cooler water throughout the system.
Gravity hot water system.
If you are in a swimming pool you will notice that the temperature of the water becomes colder as you go deeper in the pool.
When you re first filling these systems you have to start with all the radiator vents open and fill one floor at a time.
Hot water from the cylinder then travels to the home s hot water taps.
Typically such a heating system has a cold water tank in the loft or attic of the house a boiler on the ground floor and a hot water cylinder somewhere between these two.
A gravity hot water system works because the heated water which is lighter rises through the loop.
Hot water tends to rise while cold water tends to descend at the bottom of a contained space.
How to increase water pressure on gravity fed systems.
A gravity hot water heating system is the oldest and simplest system to heat homes.
In a gravity system the circulation of water is due primarily to thermal and density differences between hot and cold water.
A gravity hot water recirculation loop works by allowing the laws of nature to come into play.
An intake that is screened from debris and submerged sufficiently to ensure no air enters the pipeline a properly sized pipe diameter considering the pipeline length the elevation difference the energy available to move water and the water flow required.
As the water cools at the end of the loop where the last part of the loop is not insulated it is thermo siphoned back into the hot water heater.
The water rises to the top of the radiator and the cooler water that s in the radiator on start up falls.
Because gravity is the only force pushing the water through the pipes a gravity fed system is often referred to as a low pressure system.
A gravity fed heating system uses the force of gravity to circulate water in the heating system.
Most gravity systems had the radiators connected bottom to bottom.