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Isolation Valves – Useful Guide

Water Isolation Valves

Plumbing fixtures and fitting in homes and businesses often include many different types of fittings and one which is very useful for water leak detection (and for preventing water damage) is isolation valves which are frequently found in modern properties. They are very beneficial.

These isolation valves come in many designs, shapes and sizes but they all serve the same purpose, to cut off water (or isolate it) on part of your hot or cold water network. They work like a stop tap does, in stopping the flow to your property internally or externally.

Isolation Valve
Various Isolation Valves

Isolation valves are used in many applications, both domestically and commercially, but in this article we are talking about water valves in particular, not gas or engine valves.

Isolation Valves and Water Leaks

Isolation water valves are most commonly found close to a particular fixture or fitting in your property. In particular, they are commonly found near toilets (handy for when you have a toilet leaking), washing machines, dishwashers, taps and sinks. In fact, it is not unusual to find valves on both hot and cold water to a sink.

On the subject of sinks – see our test of Mr Muscle Sink Unblocker.

These isolation valves obviously help turn off the water supply one fitting or repairing something like a tap, or installing a washing machine. Obviously doing that whilst water is running would be impractical, difficult, cause water damage and may even be dangerous. especially in proximity to electricity.

Isolation valves are very handy when doing a water leak repair.

Boiler Isolation Valve
Boiler Isolation Valve – Filling Loop

On the subject of washing machines and dishwashers, they are some of the appliances featured in our useful article about how much water things use in your home.

Isolation Valves on Boilers

Isolation water valves are often found on central heating boilers too, including pressurised central heating boilers, but they work in a slightly different way.

Typically a pressurised central heating boiler we’ll have a ‘filling loop’ to pressurise the system. The valve is opened to fill or re-pressurise the system, such as when you’ve had a drop in boiler pressure.

The key difference with other valves is that when the boiler is operating, the valve will commonly be in the closed position, whereas something serving / connecting a toilet for example will be in the open / on position. Isolation valves can be useful when looking an leaking combi boiler systems.

How do Isolation Valves Work?

We mentioned above what isolation valves do, but how do they work? Well basically, water flows through them under normal operation and they are in the open or ‘on’ position, which may be indicated on the isolation valve.

There will have a moving part, which is typically a screw or lever which rotates at 90 degrees to the flow to cut off the water supply when the valve is in the closed or ‘off’ position.

Isolation Valves - Open and Closed
Isolation Valves – Open and Closed

Looking at the example above, you can see but when the lever is in line with the pipe or valve that it is open and equally, closed when it is at 90 degrees.

One of the most common types of isolation valve have screw head fitting and, like the example above, when the valve is open the lying of the screw head runs in the direction of the valve or pipe indicating that it is open. To close the valve, the screw needs a quarter turn isolate it.

You can see on the picture below that these two valves on hot and cold taps are both in the open position to allow water to flow to the taps (or faucets).

Isolation Valves Taps
Isolation Valves on Taps

Isolation Valves and Water Leaks

Apart from the reasons given earlier regarding installation and repairs of plumbing fixtures, isolation valves can be extremely valuable in preventing water damage to your property when you have a water leak. For example, if your washing machine or radiator is leaking, you can turn off the water supply to help prevent further water damage to your property.

You’d be surprised at how many people don’t realise they have water isolation valves on their fixtures and fittings, they call us out to help with this and our engineer will explain that they could have switched the water off to prevent the damage. So get to know where and what valves are in your property!

Isolation Valve
Isolation Valve

Isolation Valves and Leak Detection

Depending on where they are fitted, isolation valves can form a very useful role in helping to find water leaks. how is that?

Well basically, when we are carrying out inspections looking for a water leak and we know from other evidence that a leak is present, isolating a part of the system can help narrow down where that leak is. For example, if somebody is water meter is running indicating a possible leak, and it stops when a particular isolation valve is turned off – that can be a strong indicator as to where the leak is.

Similarly, when doing acoustic leak detection, if the sound of the leak stops when we isolate a part of the system that also provides further evidence to narrow down where the active water leak is.

Acoustic Listening Device
Acoustic Listening Device

Plumbing water isolation valves can be purchased from specialists places such as City Plumbing, trade DIY shops such as Screwfix or general DIY stores like Wickes. Remember that fitting such things will often require a plumber or boiler engineer so get professional help.

Other Articles Relevant to Isolation Valves

Isolation Valves – Frequently Asked Questions (FAQs)

What are Isolation Valves used for?

Isolation Valves Taps

Isolation Valves in plumbing are used to turn off the supply to a fixture or fitting in your property, or to isolate a part of your plumbing system in your home or business. They can be found on things such as taps, toilets, radiators, central heating boilers or even on things such as washing machines and dishwashers. This is also helpful for when you are installing, replacing or repairing such fittings in your property.

How do you turn off isolation valves?

Isolation Valves - Open and Closed

Exactly how you turn off valves for isolating plumbing in your home will depend on the type of valve you have but typically they will have a lever (small or large) or screw which needs turning 90 degrees to turn them off. Typically, when they are pointing in line with the valve or pipework they will be open / on and when at 90 degrees, closed / off. Many valves have markings on them to help indicate if they are on or off as well as which direction to turn them.

If you have need help finding a water leak at your home with our trace and access service, get in touch with our friendly team today. We offer these services to both domestic and commercial customers, including commercial leak detection.

As experts in both water damage restoration and leak detection, we have you covered. logo logo