MEGAFLO ECO 125L -300L PRESSURE REDUCING VALVE 3 BAR 95605886

Product Information

Pressure in an electric hot water system builds up primarily because when water is heated, it expands. If designed and installed properly, this is allowed in the system – usually through the installation of an expansion vessel. If this fails, or if one was not installed in the first place, then there is nowhere for this pressure to go when the water is heating up, and it escapes through the Pressure Relief Valve. The air volume within a cylinder should periodically be recharged to accommodate for expanded water. If water is intermittently flowing from the expansion valve then this indicates that the air volume has reduced so much so that it cannot accommodate expansion. Sometimes the warm water may be the result of heat transfer from hot pipes in close proximity to cold pipes.

Particularly important in hard water areas, descaling a cylinder can help to extend the life of a cylinder and improve performance. Before carrying out this work, turn off the mains water supply, isolate the electrical supply and turn the boiler off.Explaining the importance of an annual hot water cylinder inspection by a G3 qualified engineer is one way to help homeowners realise why this is an important service. Now, we are not qualified plumbers but what we can tell you is that in the majority of cases, pressure relief valves do not fail. They work. And what this means is that water comes out of them when the pressure gets too high. That’s exactly what they are supposed to do when the pressure needs relieving. If the immersion heater needs to be removed and replaced, careful attention must be paid to ensure that the tank is not damaged. Using the wrong tools and methods could mean ripping the immersion boss off the top of the tank, or potentially cause leaks from the immersion boss.

In one megaflo manual under 'User Instructions' there are instructions on how to "Clean the strainer" within the cold combination valve. I followed those instructions - well it did say 'user instructions'. I took particular care to remove the buildup of limescale on the rubber washers while not damaging anything. AND IT WORKED! So in these cases, the fault lies elsewhere – i.e. the pressure is too high in the rest of the system.In the same way that boilers must be annually serviced, it is also essential to professionally maintain hot water cylinders.Follow our easy steps in this article and ensure that your customers’ cylinders run as efficiently as possible and remain covered by their warranties.

George Linder, Product Manager at Heatrae Sadia, outlines how to service an unventedcylinder to ensure it is running as efficiently as possible and remains under warranty. Once the cylinder is drained, the covers to the immersion heater can be opened to allow the immersion heater thermostat to be disconnected. To lift the immersion heater out, simply unscrew it and carefully lift it out so that any scale can then be removed. It is surprising how many times we get a call from someone telling us that the Pressure Relief Valve is leaking on their electric water heater, and asking us what they should do. Before I go any further, let’s clarify that I am talking about a pressure RELIEF valve, not a pressure REDUCING valve. These are often (but not always) built into the top of an electric water. Often they are combined with a temperature relief valve. Sometimes they are on the cold supply side of the water heater. On a Megaflo cylinder, the blue handle needs to be turned so it is positioned at a 90° angle to the flow of the water. Following this, open the lowest hot tap supplied by the cylinder and hold open the temperature and pressure relief valves. This can be done by twisting the knob on top of the valve until the water and the gurgling sound at the valve stop.

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Now the pressure and temperature relief valves can be closed by releasing the knob, and the isolating valve can be turned on by turning the blue handle until it runs parallel with the water flow. Once water is flowing from the hot tap again, it can be turned off. The air volume will now be recharged as the cylinder refills.

To recharge, the heat source to the cylinder must be turned off as well as the water supply. This can be done by turning the isolating valve on either the pressure reducing valve or expansion valve. However, what is even more surprising is that many of these people have been told by their plumber that this means the valve is faulty and should be replaced. In fact, we even had one customer who had been told this by their plumber, had followed their advice and replaced it only to find the same thing happened again. So they called the manufacturer and they advised the same thing, so they bought ANOTHER valve, and … you guessed it, the same thing happened yet again.