Schematic Unvented Heating System

Megaflo or megaflow system.

Schematic unvented heating system.

Regardless of the central heating design the sundial plan is a system that controls the boilers operating periods and temperatures for space heating and or hot water. There are three types of domestic hot water system. Modern heating systems run by gas boilers tend to be unvented or pressurised. This first is a combi boiler system where the boiler directly heats the water on demand.

For an entirely new installation s plan would be a far better choice as that does not have the default open problem and also allows the use of multiple zones for the central heating. This is a system from the people over at heatrae sadia a highly recognisable and trustworthy name in the industry. Before we look at the more technical aspects of the megaflo unvented boiler system which some incorrectly call the megaflow system or megaflow boiler instead let s take a look at the basics. These are over pressurisation and overheating.

The arrangement shown here is most likely for an existing y plan system where the cylinder is being changed to an unvented one. The electric versions use a coiled heating element to heat the water rapidly in a. An automatic bypass valve is fitted inside most combi boilers by the manufacturer these days. This simply means the time the boiler starts up and for how long how much heat it provides for either space heating or for domestic hot water or both.

In an unvented system there is no header tank and the water in the pipes is under pressure. A guide to the most common types of domestic heating and hot water systems with diagrams including indirect boiler system unvented system thermal store. The diagram below shows the general layout of an unvented hot water system. When the water in a pressurised system expands the pressure in the.

No external pump no tanks no external expansion vessel no motorised valves and in many cases item 6 is not needed either. One givaway is that there is often a pressure gauge on the boiler measured in bar. Instantaneous hot water heating systems this method involves using gas or electricity to heat the water to a useable temperature without the need to store the water. Unvented systems have two basic dangers that must be addressed.

These are over pressurisation and overheating. Unvented hot water systems. This diagram illustrates how simple the heating system connected to a combi boiler is.