How does the hot water system work?

When you turn up your room stat, it powers up your heating pump. A flow switch in the boiler senses flow and fires up giving you the desired heat output which can be adjusted on the front of the boiler. The flow of the heating first goes to the immersion cylinder. There it comes to a three port valve. The three port valve is connected to a thermostat attached to the immersion. If the water in the immersion is cold, the three port valve opens to allow heating water to travel round a coiled pipe inside the immersion. With heat transferal, it starts to heat the water whilst heating the radiators as well. When the immersion stat gets to Temperature, it activates the three port valve which diverts heating water from the coil to straight down the heating circuit. You use hot water, the cylinder stat activates the three port valve again. While your heating is on you get very cheap hot water.