How does header tank work

Eventually, the oxygen-rich water will quickly ruin the entire heating system via internal corrosion if left uncorrected. Similarly, the pump must not be installed in a position which will draw air into the system via the vent pipe.

Like the cold storage cistern, feed and expansion cisterns are generally made out of plastic. Common materials include polyethylene, polypropylene, and polyvinyl chloride PVC.

Glass-reinforced polyester GRP may also be encountered. Modern plastic cisterns are generally black in order to resist algae growth. They are usually rectangular or loosely rectangular in shape.

Older cisterns may be made from galvanised steel, which is susceptible to corrosion. Some cisterns may also be made from asbestos cement. You should never attempt to cut up or even dispose of asbestos cisterns yourself.

Even in tiny amounts, asbestos particles are extremely dangerous to human health. Skin contact alone can cause nasty dermatological problems. Some cisterns may be made entirely from copper. Metal cisterns are required where water is heated by a device without any form of thermostatic control.

This is because they may have to accommodate extremely hot water, even as part of their normal operation. The feed and expansion cistern is obviously not as heavy as the cold water storage cistern. Nevertheless, it should still be situated on a flat, stable, continuous base. It should extend each side of the cistern by at least 50 mm. The base must retain its structural integrity if it comes into contact with water.

Marine-grade plywood of at least 19mm is recommended. Chipboard should never be used as it is liable to disintegrate if it gets wet. In most households, the feed and expansion cistern will be located near or next to the cold water storage cistern. On older installations, it may be suspended directly above the cold water storage cistern via a base or joists. This risks the contamination of the domestic water supply with the dirty water that circulates through the central heating system.

Such installations are as inadequate as they are dangerous. The ball valve in a feed and expansion cistern is set so that when the central heating system is cool, the water level is only slightly higher than the outlet at the base of the cistern.

This is so that the water in the central heating system has the space to expand when heated. When it comes to replacing your existing boiler, you might want to consider switching to a sealed system and remove the risk of header tank overflow altogether.

Unlike open vented systems, sealed systems don't have a header tank in the loft, instead, they have an expansion vessel that's often fitted into the boiler itself.

While an open vented heating system can only work with regular boilers, sealed systems can work with combi, system and regular boilers. A heating engineer can let you know the most suitable heating system for your home based on the size of your property and the demand for central heating and domestic hot water. You can get free quotes from heating engineers based in your area using Boiler Guide. Adam is our resident home heating expert.

His experience and advice has helped millions of customers improve the efficiency of their homes and save money. Find the best boiler for your needs, or see how the latest A-rated boilers compare with each other and your existing one. Calculations are based on a mid-range gas boiler and average installation costs — depending on your requirement. Get the best quotes, fast! Over 5, engineers across the UK Gas Safe registered engineers. No delays! Excellent 4. What's in this article?

What is the header tank? What can cause header tank overflow? How to turn off the mains water supply Would a sealed system be better for your home? Find a local heating engineer. Get a quote to repair your central heating system now.

Are you a Gas Safe engineer? About the author Adam Adam is our resident home heating expert. Compare boilers Try our boiler comparison tool. Susanne Neumark Explainer. How do I drain my central heating header tank? Quick Step Checklist for Draining Down. Check that you have an open vented heating system consult with a qualified plumber if not Turn off the gas or electricity supply to your boiler or make sure that any solid fuel based boilers are out.

Lock off the ball valve in your feed and expansion tank. Scherezade Slaughte Explainer. Why is water coming out of my overflow pipe? A leaking overflow pipe means that water is entering a cistern when it shouldn't. This is usually due to a faulty ball valve. If it is extremely close to the overflow , or higher than the level marked by residual limescale, then that may indicate the cistern in question.

Odile Sargk Pundit. Do I need a cold water tank in the loft? Vented systems require a cold water tank in the loft , but going unvented means this is no longer necessary, so it's easy to save that space if you decide to go this route. Edelmiro Yachmenkov Pundit. How do I know if my expansion tank is bad?

Tap on the tank. It should be hollow about half way up. Check the temperature by feeling the top and bottom of the tank. The tank should be warm on the bottom and cool on the top if it is working properly. Use an air gauge to check the pressure inside the tank. Check to see if your release valve is spurting water. Bunny Villamisar Pundit. How often should expansion tank be replaced? If you don't have an expansion tank in your system, you really should get one. Expansion tanks will normally wear out after anywhere from years.

To extend their service life as much as possible, it's vitally important to match your expansion tank's air pressure to your house's water pressure.

Bousselham Essan Teacher. How long do expansion tanks last? The average life of your tank can be anywhere between five and 10 years. You can extend the life of your expansion tank by making sure that your home's water pressure matches the air pressure in your expansion tank. But in some cases, you'll need to replace it. Fahad Kurten Teacher.

Can a bad expansion tank cause water hammer? Although an expansion tank may help solve a thermal expansion problem, water hammer may be so powerful that an expansion tank won't take care of the problem.