Megaflo- Tight hot water taps water dripping at overflow

[noidea121]

Got a Valliant boiler (ecotec 630) connected to a megaflo installed about 2 years old.

Every time I turn the hot water on at the programmer, after about 20 mins the hot water tap in the kitchen and both hot water taps in the bathroom become quite tight. On opening there is gush and then the pressure is fine. Once one tap (doesn’t matter which) has been opened for a few seconds then the other taps are no longer tight. However if the hot water light (on the programmer) is still on then once again after about 20 minutes the taps become tight. Once the water light is off (we have it on for about 90mins) then there is no problem. This has been happening since it was put in.

I have also noticed that as the taps become tight water is coming out of the overflow. I am 99% it isn’t directly out of the megaflo tank. I have replenished the airgap in the megaflo but like I say I don’t believe it is from the tank directly and only happens when the hot water is turned on.

On the picture (A) I don’t believe it is coming out of the blue/grey coloured part (think it’s called temperature pressure relief valve) on the tank but rather from the pipe coming horizontally across the tank with insulation on it and joining the pipe that does come out of pressure relief valve. I can see/touch the water dripping inside the black plastic just below where the two pipes meet (picture B) and then the water flows through the pipe and out of the property and into my garden.

I have also noted that once I do open any of the hot water taps then the water stops dripping at the overflow on the tank.

Does anybody have any ideas as to the reason.

Could it have something to do with other valve in the picture (close up picture C) to which the horizontal pipe is connected?

Not a plumber so please keep the technical stuff as simple as you can, thanks. Just concerned about any safety issues.

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[gaswizzard]

I would suspect the unit hasn't been recharged correctly (air gap non existent) , the whole unit should be drained completly and refilled hence the reason for the overpressure and 'tight' tap heads.

Call someone who holds the relevant ticket (G3).

 

[noidea121]

I would suspect the unit hasn't been recharged correctly (air gap non existent) , the whole unit should be drained completly and refilled hence the reason for the overpressure and 'tight' tap heads.

Call someone who holds the relevant ticket (G3).

Thanks for the reply, wouldn't water be leaking regardless of whether the hot water light was on if it was just the airgap.

Also forgot to add that when I once turned the valve in picture c i got the same gush that i get at the taps and then it didn't drip for another 20 mins.

Thanks again.

 

[gaswizzard]

Without an air gap the water has no way of expanding when heated , this puts extreme pressure on pipework/fittings etc , hence the reason the taps are difficult to open , I have a megaflow in my house at home and when the air gap depletes the taps get 'stiff' (quarter turn disc) , have the unit drained and refilled , possibly the 'flying saucer' within the unit has turned on itself causing the water to absorb the air at a faster rate , or maybe just that the unit hasn't been serviced for a while or the water temp is too hot which will again deplete the 'bubble' at a faster rate.

 

[noidea121]

Have added several extra pics to the original post.

The temperature on the boiler(heating dial)) is about 60C, I have been told that the dial for water on the boiler does nothing, and that temperature is controlled by the heating dial.

The temperature on the Megaflo has been set in the grey box on the Megaflo tank itself, the thermostat is between the number 2 and 3 goes up to 5.

My installer thinks the problems may be caused by the valve shown in picture "8extra" closeup shown in pic "C" see below, does anybody have a view on this, i do belive the water is coming from here and making it's way to the tundish.If it is from here would it be airgap related.

Also rang Heatrae sadia they said that to recharge the airgap I should drain the tank from the bottom of the tank, because the lowest hot water tap in the house is on the same level as the tank itself (i.e ground floor of the house)and therefore following the procedure stated on the tank would not work. Couldn't help with the tight taps though.

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[gaswizzard]

What a mess , for starters the discharge pipe doesn't conform.

Why not call someone who has the ticket to work on these units? , it's not rocket science what the issue/s are with regard to your problem but unfortunately can't be posted on here due to the risk of 'tinkering'

 

[noidea121]

What a mess , for starters the discharge pipe doesn't conform.

Why not call someone who has the ticket to work on these units? , it's not rocket science what the issue/s are with regard to your problem but unfortunately can't be posted on here due to the risk of 'tinkering'

Sorry I only checked for gas safe register card, made sure i got a powerflush thought I covered everything, in fact on mentioning "G3 qualified" today to others who have megaflo installed i get a strange and worried look about their own installations

 

[PlumbGas]

there's no way that's a min 300mm drop from the tundish before the first bend. tut tut tut