Why does my expansion vessel keep losing pressure? If your boiler keeps losing pressure it could be from a failure in the expansion vessel. The expansion vessel is also known as an expansion tank. The
Why does my expansion vessel keep losing pressure?
If your boiler keeps losing pressure it could be from a failure in the expansion vessel. The expansion vessel is also known as an expansion tank. The expansion vessel prevents the boiler pressure relief valve, releasing water to reduce pressure, simply from the expansion caused by the hot water.
Can a faulty expansion vessel cause pressure loss?
3-You have a faulty expansion vessel You have a faulty expansion vessel- This means your boiler pressure will exceed 3 bar during the heating up process. When the system cools down you will find the water lost will now show on the pressure gauge as a significant drop.
How do I know if my expansion vessel is faulty?
If water comes out of the valve you have a definite expansion vessel fault. In this case the vessel has definitely failed and must be replaced. If no water comes out but no air either, you have an expansion vessel fault but the diaphragm may still be intact and it may be possible to re-pressurise.
What pressure should my expansion vessel be?
Some important things to consider is the air pressure inside the expansion vessel. It rarely needs to be anything more than 1.5 bar in most domestic properties. Anything more and the water may not expand into the air at the required time and could risk the high pressure relief valve opening or worse.
What pressure should a expansion vessel be set at?
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.
How much pressure should an expansion vessel have?
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 if expansion tank pressure is too high?
If the psi is too high, you can simply let some air out by pressing down on the valve until enough air has escaped. If the psi is too low, you’ll need to add some air with a tire pump. We highly recommend using a hand pump instead of an air compressor when adding air. An air compressor could easily rupture the bladder.
What should the pressure change be on an expansion vessel?
If it is working correctly, the pressure changes are normally less than 0.5 bar (½ bar) up and down and are quite slow. Big swings in central heating system pressure indicate expansion vessel faults.
What causes an expansion vessel in a boiler to fail?
We’ve explained how these vessels work in our Boiler Pressure article. An expansion vessel may fail by rusting through and leaking water. This is a less common cause of failure, particularly in systems which have had good quality, long-life corrosion inhibitor liquids added to the water.
What should I do if my expansion chamber is not pressurised?
To re-pressurise correctly you must drain water from the system until the pressure is zero. If you don’t do this you can’t set the expansion chamber pressure correctly. It’s important to leave the water drain valve open while you re-pressurise the vessel.
What do expansion vessels look like in central heating?
Central heating system expansion vessels are usually red but could also be grey. If they are within boilers, most are flattened, lozenge shaped, to allow them to fit more easily. External to the boiler they are usually spherical and the size of a large football. As we’ve said, the size required depends on the size of the heating system.