Variable Air Gap Device
Product Information
The Variable Air Gap Device is a component designed to be fitted
on the water inlet between the pressure reducing valve and the
cylinder. It is manufactured by Flexiheat UK, located at Unit 49
Azura Close, Three Legged Cross, Wimborne BH21 6SZ, United Kingdom.
For any inquiries or sales-related questions, you can contact
Flexiheat UK at +44 (0) 1202 822 221 or via email at
[email protected].
Product Usage Instructions
- Attention: All work related to an existing operating system
should be carried out by a suitably qualified installer. - Ensure that there is a minimum of 80mm pipe length between the
compression fitting on the Air Gap Device and the pressure reducing
valve. - For ease of maintenance, it is recommended to add a water inlet
shut-off valve before the pressure reducing valve. - The Air Gap Device can be mounted vertically or
horizontally. - It is also recommended to position the device above the level
of the T&P (Temperature and Pressure) on the vessel to aid in
future maintenance. - Follow the commissioning process for the internal expansion
cylinder as per the installation manual.
Variable Air Gap Device
This device is an improvement to unvented water heating installations. In accordance with B.S. 7206: 1990 to accommodate for the expansion of the water as it is heated inside the water tank an external pressurized expansion vessel is coupled to the tank. Over a period of time the expansion vessel will lose its charge & will have to be re-pressurized. An alternative to fitting an expansion vessel is to arrange for a volume of air to be provided above the water level inside the water heater (internal expansion). This will eliminate the need for the external expansion vessel & reduces installation time. The tendency with internal expansion is over a period of time for the air to be absorbed by the water. When this happens a procedure needs to be carried out to manually replace the air in the vessel. The patented Air Gap Device automatically re-charges the air gap in the vessel every time water is drawn off by the user.
Flexiheat UK Unit 49 Azura Close, Three Legged Crose.Wimborne BH21 6SZ,
United Kingdom t: +44 (0) 1202 822 221 Email: [email protected]
Attention – all work to an existing operating system should be carried out by a suitably qualified installer.
The air gap device is fitted on the water inlet between the pressure reducing valve and the cylinder per diagram below. Ensure that a minimum of 80mm pipe length exists between the compression fitting on the Air Gap Device and the pressure reducing valve. For ease of maintenance you may wish to add in a water inlet shut off valve before the pressure reducing valve.
The Air Gap Device can be mounted vertically or horizontally We also recommend to position the device above the level of the T&P on the vessel, this will aid any future maintenance. Follow commissioning process for the internal expansion cylinder as per installation manual:
Flexiheat UK Unit 49 Azura Close, Three Legged Crose.Wimborne BH21 6SZ,
United Kingdom t: +44 (0) 1202 822 221 Email: [email protected]



















