Indirect Cylinder or Direct cylinder - which to choose?
At Electrical Deals Direct, one of the most common questions we come across from our customers is "What's the difference between indirect & direct cylinders?" Certainly this is understandable, the world of electrical appliances and especially electric Water Heating can be tedious. Many numbers, acronyms, and much industry jargon may be more of a headache than its worth, we'd like you to be able to feel educated without being overcome with part numbers and rubbish, that's our job! Here we will attempt to simplify the differences in understandable words, and help you in understanding or choosing from an Indirect or Direct cylinder.
Indirect
An Indirect Cylinder is heated by a separate boiler. This is to say, the cylinder does not use its own electric elements to provide heat to the water. Instead, the heated coil imparts this to the "potable" or fresh water in the tank. Indirect units need another source of heat. such as a gas or immersion boiler. Popular ranges like the Megaflo will point out their indirect models with an 'i' following the literage (like so) Or OSO will use SC (like so). In brief: Indirect needs external appliances to apply the necessary heat to the cylinder.
This may prove confusing, but consider this process in comparison to the Direct cylinder:
Direct
A Direct cylinder heats the water itself, using elements within the cylinder. Consider the Direct system as its own electric immersion, removing the need for an external appliance like a gas or alternate electric immersion heater. Consider the Direct as heating the "potable" fresh water within itself as opposed to the Indirect method of heating externally. Popular ranges like the Megaflo will point out their direct models with "D" (like this) - Where DD or DDD indicated the number of heating elements inside the cylinder. OSO likes to denote their cylinders with SX (as so). Note that direct models will need appropriate expansion vessels installed within the property, be sure to check either with our friendly team over the phone. To summarise: Direct Cylinders heat the water inside the cylinder with its own heating elements, passing the water on to be used as needed.
