Programmers and time switch

"The difference between a programmer and a timeswitch is the amount of channels it can hold. A timeswitch can only handle 1 channel and a programmer can handle more than one. A programmable channel means an aspect of heating or hot water that needs to be controlled. central heating can be 1 channel and hot water can be another. In most domestic homes most the maximum number of channels will be 2. You may need more than two if you would like to zone off different rooms for central heating and bathrooms for hot water. For example, you have 1 bathrooms and three floors. You want to program the times the central heating on each floor to comes on. you want it to come on at different times of the day. In this scenario you need a 4 channel programmer. 1 channel for the hot water and 3 for the central heating as each floor is a zone. "