As the name suggests, a duo valve (non-return isolating valve) has two functions. Firstly, it shuts off the water supply to your hot water system. Secondly, it has an in-built non-return valve to stop hot water from your tank backflowing into the cold-water line, which will happen as the pressure inside your storage tank increases above the mains cold water pressure, during the heating cycle due to expansion.
It is important to know where your isolation valve is as it allows you to stop or slow a hot water leak or service your hot water system without turning all the water off to your home. A duo valve should be found on the cold-water inlet side towards the bottom of your hot water system if the tank is in an accessible area. Otherwise, start looking around your house to locate it, as hot water leaks can increase electricity and water bills and it’s almost guaranteed you’ll need to shut off your hot water one day.
Newer duo valves typically have a blue quarter-turn handle, whereas older duo valves may have a black circular handle that you may need to turn a few times (clockwise) to shut off the flow of water. Your system may also have an older isolation valve that looks a bit like a brass garden tap handle. This tap style does not have the non-return feature and is prone to leaking.
How do I know if my isolation valve is working?
Over time, your isolation valve may stop working due to debris getting stuck, minerals in the water reacting with the mechanism or internal components perishing over time. The newer quarter-turn models are much easier to turn on and off and are more reliable. The older black and brass handle spindle-type isolation valves may not shut off the water completely and can also be harder to turn.
It’s also worth noting that if you have a new isolation valve installed, you may notice your pressure relief valve dripping more than it did in the past. This is normal, as the non-return function prevents the heating and expanding water to backflow into the cold inlet pipe and instead pushes it out of the pressure relief valve (as it is designed to do) during a heating cycle.
How 6 Star Hot Water & Plumbing can fix your hot water isolation issues in Canberra and Queanbeyan
All our new hot water installations come standard with a new duo valve so you have peace of mind knowing you can shut off your hot water for an emergency or future maintenance. We can also replace your older valves that can be difficult to turn off or that are leaking. Call a qualified plumber today on 0448844911. We service Canberra, Queanbeyan and surrounds.
Hot water duo (non-return isolating) valves we repair or replace:
- Apricus – non-return isolating valves
- Aquamax – non-return isolating – duo valves
- Beasley – non-return isolating – duo valves
- Chromagen – non-return isolating – duo valves
- Conergy – non-return isolating – duo valves
- Dux – non-return isolating – duo valves
- Edwards – non-return isolating – duo valves
- Everhot – non-return isolating – duo valves
- EvoHeat – non-return isolating – duo valves
- Hills – non-return isolating – duo valves
- iStore – non-return isolating – duo valves
- Kelvinator – non-return isolating – duo valves
- Quantum – non-return isolating – duo valves
- Reclaim – non-return isolating – duo valves
- Rheem – non-return isolating – duo valves
- Rinnai – non-return isolating – duo valves
- Solahart – non-return isolating – duo valves
- SolarArk – non-return isolating – duo valves
- Stiebel Eltron – non return isolating – duo valves
- Thermann – non-return isolating – duo valves
- Vulcan – non-return isolating – duo valves
How do I turn off an isolation valve?
To turn off your isolation valve, turn the handle clockwise. If you have a round black plastic handle or brass T-head, you will need to turn the handle a few times to stop the flow of water. If you have a blue quarter-turn handle, you will need to turn the handle so it is perpendicular to the valve.