Unvented systems have two basic dangers that must be addressed.
Schematic unvented heating system.
No external pump no tanks no external expansion vessel no motorised valves and in many cases item 6 is not needed either.
When the water in a pressurised system expands the pressure in the.
Over pressurisation can be caused by a failed pressure reducing valve while overheating can occur if an unvented cylinder overheats and the water continues to increase in temperature and.
Unvented hot water systems.
One givaway is that there is often a pressure gauge on the boiler measured in bar.
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.
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.
In an unvented system there is no header tank and the water in the pipes is under pressure.
These are over pressurisation and overheating.
There are three types of domestic hot water system.
Visit the unvented cylinder page on our interactive house for comprehensive information on unvented hot water systems.
An automatic bypass valve is fitted inside most combi boilers by the manufacturer these days.
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.
This is a system from the people over at heatrae sadia a highly recognisable and trustworthy name in the industry.
This first is a combi boiler system where the boiler directly heats the water on demand.
Megaflo or megaflow system.
The diagram below shows the general layout of an unvented hot water system.
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.
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.
A guide to the different ways of heating domestic hot water so you can identify problems and faults with the hot water tank or central heating system and carry out any maintenance needed.
This diagram illustrates how simple the heating system connected to a combi boiler is.
