Megaflo overflow dripping

Why is the megaflo overflow dripping? Solving this problem is a normal part of owning a megaflo hot water cylinder and is the kind of maintenance the manufacturer encourages you to do yourself.

Megaflo hot water cylinders are designed to have an air bubble caught in the top of the hot water tank. This is to help manage the pressure inside the tank rising as the water heats up.

Over time this air bubble is lost so needs to be reinstated.

Megaflo hot water cylinder. The top section contains the bubble
Megaflo hot water cylinder. The top section contains the bubble

How to reinstate the Megaflo air bubble.

How to reinstate the air-bubble on a Megaflo Cylinder Water intermittently dripping / flowing from the overflow on a Megaflo Cylinder is usually caused by the air-gap not being fully charged. Follow these instructions to replenish the air-gap and solve the problem.

  1. Turn off the mains cold water supply to the Cylinder, this is usually found near the Cylinder, or if you can’t find this valve you can turn off the mains stop cock which can usually found under the kitchen sink.
  2. Open the lowest hot tap in the property. This would usually be the kitchen sink but any sink lower than the cylinder will be fine.
  3. Hold open the temperature / pressure relief valve. Water will pour from the valve for up to 15/20 minutes (but is normally much less). You must hold the valve open for this time. If the water hasn’t stopped flowing after this time the mains water supply may not be fully turned off.
  4. When water stops flowing from both the valve and hot tap close the temperature / pressure relief valve.
  5. Open the mains cold water supply.
  6. When mains water is turned back on water will pour from the hot tap. Close the tap when any excess air bubbles have been allowed to escape.

If this doesn’t work and water still comes from the pipe then you must call a qualified engineer.

Advise your engineer that it is an unvented tank as they need to have extra qualifications that some don’t have.

Hot water cylinders can be serviced by the manufacturer. Click on this link for more information.

Further reading

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