Megaflo Air Gap Replenishment

[*Dan*]

I am trying to replenish the air gap on my Megaflo water cylinder which is approx. 5 years old and noticed water dripping from the tundish when the hot water cylinder is being heated.

I have followed the instructions in the manual and on a youtube video from haetrae sadia which involved me turning off the cold water feed to the cylinder and then opening the lowest hot water tap in the property. The cylinder is located upstairs on a two storey property. I have kept the hot water tap open on the lowest point for at least fifteen minutes and the hot water still continues to trickle out at a slow pace but doesn't seem to stop completely. I tried turning off the main stopcock in the kitchen just to be sure the water to the cylinder has been cut off and it doesn't help.

I cant get to the next stage of turning the T&P valve as the hot water doesn't seem to want to stop. Any ideas or do I just need to be a little more patient (even though the videos I watched seemed to suggest it would only take a few minutes to stop).

 

[oldbuffer]

1. Sounds as if the cold feed hasn't turned off completely.
2. If you've turned it off at the black plastic handle on the combination valve, in my experience these are often very stiff and don't always work well. Try turning it off at the oncoming main.
3. The hot water feed is driven by the incoming cold water pressure, so once that pressure has gone there is nothing to drive the hot water. It should certainly stop flowing in less than 15 minutes.
4. A further possibility is a mixer tap feeding cold back into the hot supply, but unlikely as you say the continuing water flow is hot.

 

[*Dan*]

1. Sounds as if the cold feed hasn't turned off completely.
2. If you've turned it off at the black plastic handle on the combination valve, in my experience these are often very stiff and don't always work well. Try turning it off at the oncoming main.
3. The hot water feed is driven by the incoming cold water pressure, so once that pressure has gone there is nothing to drive the hot water. It should certainly stop flowing in less than 15 minutes.
4. A further possibility is a mixer tap feeding cold back into the hot supply, but unlikely as you say the continuing water flow is hot.

Thanks for this. Another thing to add is that there are two hot taps downstairs - one in the kitchen and one in the cloakroom. The one in the cloakroom which I thought was the lowest point of the hot water is the one that is constantly running even with the cold off at the mains and on the combination valve. The kitchen hot tap actually stopped running after a couple of minutes but the hot tap in the cloakroom still runs with hot water albeit a very weak flow.

As you say I cant get my head around why I would be getting hot water out of this tap with the cold supply off but the kitchen hot completely stops flowing. The main stopcock is working as I checked the cold taps and no water was flowing out of them.

 

[ScottishGasMan]

If its just a trickle you may be able to open the TPR Valve and still have it dump water faster than its coming in and still make a new air bubble in the cylinder, worth a go before replacing the main stopcock