HELP PLEASE....pressure lost

[Hush]

I apologise, but this is my first post.

Around 6 months ago, noticed loss of pressure and occasionally observed water spilling out from discharge outlet, which is somewhat not as frequent as before.

Now, I'm having to keep topping up the water everyday, as the pressure goes down to almost zero from 1 bar within 24 hours. The boiler is floor standing Potterton Kingfisher MF 100 with megaflow tank. The tank is in the attic.

Also, had the radiators from the ground floor replaced and have had new flooring put in. My nightmare! is that I don't want to rip the floor out and break through the concrete floor extension to find a possible leak.

I've put some Fernox leak sealer, but this does not seem to have improved the situation.

Also, went up in the attic today and found that COLD water is discharging at about 1 drop every 10sec. COULD THIS BE THE CAUSE OF PRESSURE LOSS? If so, what do I need to do?

There is a valve (3bar) adjacent to another valve with blue top (8 bar) in between the mains and the megaflow tank. The connection from the 8 bar valve leads to overflow and another end to the tank. Is this valve the culprit, if so how do I change it? Do I need to isolate the mains flow and then simply replace or do I need to take further precautions?

Please help. :

 

[oilman]

Is this valve the culprit, if so how do I change it?

If it IS the culprit, YOU don't do anything. You have to be licenced to work on unvented systems. The good news is the pressure drop is nothing to do with this valve.

The pressure drop is on the heating system side, and is probably the expansion vessel having lost its air charge (usually a result of inadequate servicing). Search the forum for "expansion vessel" AND "filling loop".

 

[Hush]

Thanks for the tip Oilman.

Since then, I called a local pumbers who keeps charging me £81 for every visit and tells me that It might be the expansion vessel!

I also noticed, that the discharge from the PRV near megaflo tank is around 1drop/20sec when system is not on and around 1 drop/10sec when system is on. I hope, that it is the expansion vessel.

IS IT WORTH GETTING IN A PLUMBER TO CONFIRM THIS OR SHOULD I BE INVESTING FOR A LEAK ELSEWHERE?

your help is always appreciated.

Hush

 

[Hush]

OILMAN

Sorry, but another thing is that I had let the water in couple of times (around 2 months ago) well beyond 3 bar. I am now wiser after leaning from the site. Also lot of water was discharging (2-3 months back) for about 5 minutes, and this use to happen periodically. I havn't noticed heavy water discharge for some time now. Mind you, if it happens at night or day then either I'm asleep or at work!

The entire system has never been serviced since it was put together (>4 years) other than water pump changed 2-3 months back.

Hush

 

[oilman]

If the water is coming from the megaflo, have you regenerated the expansion space? You do this by turning off the service valve to the megaflo. Then open the lowest hot tap, the water SHOULD flow for quite some time. If it doesn't, open the valve on the side of the megaflo and keep it open until the gurgling stops. About 20mins. Close the valve on the side of the megaflo and open the service valve. When the air stops coming out of all of the hot taps, turn them off. The megaflo will then repressurise.

You will find these instructions in the Megaflo manual.

 

[Hush]

Thanks OILMAN

Thanks for the tip. I'm going to try that and see what happens. If all goes well and pressure still drops.....could it then be the expansion tank? call for plumber then I guess or is it easy to fix?

Cheers

Hush

 

[ChrisR]

Your OTHER problem - the one where you're losing ressure on the heating system, is due to the water going out through the pressure relief pipe. Once they have water going through them, they almost always don't shut properly so continue leaking, so you keep losing pressure. Hopefully one of your 81 quids got you a new pressure relief valve?

Ther will be a pressure (expansion) vessel on the heating, which is probably a red blob shaped thing, which could be almost anywhere. It should have air in it, which gives the water somehwere to expand to when it gets hot. Eventually the air leaks out so the thing is full of water. That means that the water has to squirt out of the pressure relief pipe.
So, hopefully, another (!?) £81 saw a man with a car foot pump or similar pumping the pressure vessel to the correct level. If he got water out from where the air should be, then yes, you need a new pressure vessel because the internal rubber separator has failed.

 

[Hush]

OILMAN,

I tried the first option of regenerating the expansion space in the megaflo, as per instructions.......HW and CH were fine and the pressure upto 1.4bar stabalised whilst the system was on full blast. But, when I turned the system down the pressure droped to 0.8bar and this morning down to 0.1bar.

I noticed, that after regenerating the megaflo and HW/CH on for 3 hours there was lot of air blasting out together with hot water on a tap which I opened. This soon stabilsed.

There is still small drops of discharge!

....and by the way the first 81 quid only got me a statement saying "possible leak in the system" and nothing else not even PRV.

Hush

 

[oilman]

....and by the way the first 81 quid only got me a statement saying "possible leak in the system" and nothing else not even PRV.

Fine, I'll get my £246 bill in the post right away!

Get someone else next time, someone more useful.

 

[kevplumb]

£ 81 quid to tell you its not working
please e mail me your address
at that price it would be worth the diesel

 

[Hush]

Apology, but been extreamly busy at work and so no time to do anyting except keep topping up water to pressure the system.

So, in a nut shell, I guess I've either got a leak in the system or that the expansion tank is buggered.

I guess I'll call in a plumber to replace the tank, since I'm not sure how to fix this other than

shutting off mains to megaflow
draining the rads
but then I can't see any valves near the floor standing potterton boiler.

Should I be looking for any other valves or anything else to fidddle with before slapping on another expansion tank? or is it best to call a plumber and get him to do it?

Thanks

Hush

 

[ChrisR]

On the boiler/heating system:
I see no evidence that you need a new anything, except a new plumber, and probably a pressure relief valve. The pressure vessel precharge needs to be checked and set to the correct level, and the prv replaced or repaired so it doesn't leak.
Then you decide if anything further is required.

I'm not sure if your Megaflo is still dripping. If so, you may need a new valve there too.