Does an unvented cylinder need an expansion vessel?
Unvented systems are ‘sealed’, so they require an expansion vessel either next to or incorporated within the boiler or cylinder. An expansion vessel allows for the expansion of water in the system as it heats up, and accommodates the increase in pressure by up to 4.5%.
What pressure should a unvented cylinder expansion vessel be?
around 2 bars
As unvented cylinders work from the power of the mains water supply, the mains pressure and flow rate must be adequate. Supply pressure should be around 2 bars and able to supply the required flow rates.
Is an expansion tank really necessary?
An expansion tank is always highly recommended if you have a ‘closed-loop system’ caused by any kind of check valve or pressure regulating valve installed on your house’s water supply line. A common illustration compares having high water pressure in your home to having high blood pressure.
Do I need an expansion vessel?
As we all know, when water is heated it expands and wants to take up more volume. As the system is basically a closed loop, consisting of the boiler, pipework and radiators, it is necessary to provide some space for the water to expand into. This is why the expansion vessel is required.
How do you know if your expansion vessel is broken?
An installer can usually tell if the expansion vessel has failed as the boiler pressure gauge will show a great increase of pressure as the boiler heats up. A faulty expansion vessel will not always need replacing – often it will simply need repressurising.
How do I know if my expansion vessel failed?
If you think the vessel has failed, unscrew the plastic cap from the pressurisation valve (it’s like a car tyre valve). Momentarily depress the pin in the valve to release a little pressure. If water comes out of the valve you have a definite expansion vessel fault.
What pressure should I set my expansion vessel to?
Summary. Expansion vessels, also known as expansion tanks, keep the pressure in a combi boiler stable while water heats and cools. They are typically located inside the boiler casing. The typical pressure a boiler system should be set to is 1 bar.
What happens when boiler pressure is too high?
If the boiler pressure is too high, there’s an increased chance of leaks developing in the system. But if boiler pressure is too low, the system won’t work as well. So keeping the correct boiler pressure is important to make sure that your system heats your home efficiently.
What can I use instead of a expansion tank?
Thermal Expansion Relief Valve
The Thermal Expansion Relief Valve can replace a water heater expansion tank because it functions similarly. Both products absorb the excess pressure in the plumbing system created by thermal expansion.