Heatrae sadia megaflow

[cooperman36]

Hi, i have a megaflow hot water and heating system about 12 years old, i have a constant drip/run into the funnel like overflow which is connected to the pressure relief valve.
the mains inlet to the cylinder goes through 2 valves one 3bar then an 8 bar, there is a small pipe out of the side of the 8bar valve which tees into the overflow pipe just above the inspection funnel mentioned above.
I am trying to work out if the running water is from the pressure relief valve or the tee? The running water is cold.
Also on the side of the 3 bar brass valve is a black plastic handle looking bit with a hex built in, and with inlet water to the cylinder turned on water seeps through the plastic bit which is obviously wrong but i wondered if this is connected with my issue?
I have regularly carried out the air gap procedure so don't believe this is the current issue.
Thank you
Lee.

 

[twgas]

work on unvented cylinders should be done by a G3 qualified plumber/heating engineer, DIY is not advisable.

 

[cooperman36]

Thank you Mick, i am aware of that requirement however i want to understand what's wrong to avoid be conned. I am sure you are aware of how tight money is at the moment.

 

[twgas]

I understand the money stuation, however if you get advice here what's to stop anyone reading it and playing with their, potentially dangerous, systems?

 

[cooperman36]

That's why this forum came about isn't it?
i am a mechanical engineer and using reasonable intelligence and common sense we have to make our own choices in life.
Personally i wouldn't touch the cylinder but changing an external valve or fitting which are compression jointed i think i am more than capable of being done safely.
I also believe some people will have a go whatever we say and some people have no choice as there is NO spare money, giving them some help and knowledge will surely make it less dangerous?

 

[twgas]

with all due respect, I have no way of knowing whether you or anyone else reading this is capable or competent to do this or any other work.
and you do not know if I am qualified or knowledgable enough to advise you.
I agree we all have to make choices but if I give you the wrong advice and a serious incident happens whose fault is it. so I'm happier giving no advice on safety critical parts/systems.
sorry if you are not happy with that but thats how it is.

 

[cooperman36]

I am not unhappy about anything but thanks for asking.
If the first two lines of your last reply were applied then nobody on here would give or take any advise or help on anything Mick.

If anyone can help with advise or information on the question posted i would be very Grateful
Thank you

 

[scoobydo123]

Could be just a bit of dirt on the seat of the valve if you have been regularly regenerating the air gap (I have one that hasn't been touched for 3 years). Obviously leak from the pressure reducing valve is another issue.

 

[cooperman36]

Thank you for answering, i have open and shut the valve several times during the procedure for recharging the air gap today, also the continuous run of water is ice cold when i know the cylinder is hot.
Would be good to know what the two valves on the mains inlet to the cylinder (in my photo's) actually do?

 

[picasso]

If the water is cold that is dripping into the tundish then its the 8 bar valve that is passing, could be the pressure reducer has gone or your getting back feed from the hot water system (cold water passing into the hot water system) I would advise you to get someone in, these can be dangerous for diyers.

 

[cooperman36]

Thank you for answering, for the back feed example you give what is actually at fault? If a plumber says i need a new Megaflow cylinder for example i wouldn't know if that is plausible, so just trying to know what to expect in my own mind
Thank you.

 

[picasso]

The back feed is normally caused by non return valve passing, I think your pressure reducer has failed but you need someone that is competent working on unvented cylinders to know for sure , where about in essex are you ?

 

[cooperman36]

Thank you for the Info and being Honest.
In the Rodings, 8 miles West of Chelmsford.

 

[picasso]

If you want your cylinder looked at I can recommend someone or if your willing to wait for a week I can do it, I am based in chelmsford.

 

[cooperman36]

Thank you Picasso, only noticed the issue Yesterday morning and have been trying to get hold of the Plumber who installed it but no luck yet. I will keep trying him until Tomorrow then i will consider your offer which is much appreciated. Do you think its safe to use for a couple of days with a small continuous trickle of water down tundish and water slow dripping out of plastic bit of this valve (which i have a dish under at present)?

Any chance of some prices for call out and looking and maybe if the pressure reducing valve needs changing?
Thank you