An understanding of electrical wiring diagrams is essential for HVAC system updates in older homes. Older homes especially are prone to electrical wiring problems. When these homes were originally built many appliances did not exist, like dishwashers, dryers and air-conditioners. The electrical wiring in older homes is hardly ever adequate to sustain the many modern appliances people use today.
Heating, vacuuming and air-conditioning systems (HVAC) are large systems that require plenty of energy to operate. In addition to understanding the load your electrical wiring can handle, schematics help you establish where to put thermostats, and which style of wiring you should use for your HVAC system.
There are two types of schematics. Some come in data sheets and technical documents. These schematics show only the circuit (or partial circuit) and perhaps a few notes. The other type is the actual drawing used to create a circuit board. These schematics represent a full system and include more information, like the author's name.