Water pressure dropping to 0 in matter of hours

[smg086]

PLEASE CAN SOMEONE HELP ME ON THIS:
Been having so much hassle with my boiler lately - a Vokera mynute 13 e.
Firstly after bein on for bout 40 mins it wud cut out and NOT Re-ignite (ie.the red pilot light wud come on and i had to physicall restart it. So i decided after asking 2 plumbers that could not solve the prob, i went to Vokera themselves.
Straight away they fixed the prob (he told me all he had to do was top up the GAS PRESSURE. so obviously i was delighted but unfortunately from that day on i'v been having another prob - the water pressure on boiler drops rapidly (i'm having to top up the pressure twice a day as it goes to absolute 0 therefor not a kick out of the boiler)
I got the guy back from voker and he changed some part on the boiler (he said basically if im still loosing pressure to get a plumber as he replaced the only part on the boiler that cud leak) anyway this goin on few weeks now with me toppin up every day but just yesterday i noticed in my spare room the radiator stone cold even the 2 pipes leading to the radiator are stone cold. can anyone help is this all related?
Vokera were very expensive so i cant really afford to go n spend a fortune again
please - any advice wud be appreciated.
ps. there is no obvious leaks anywhere in the house

[NJ Trooper]

I'm not sure you will find anyone here that knows anything about your boiler... it's an unknown brand here for most part... nearly all of us here are in the USA...

If the pressure in the boiler is going to zero, then I think there must be a leak, even if you can't see it... where else would the pressure go? Any pipes under the house that you can't see?

[smg086]

Thanks a lot for your quick reply. yes im sure there is some pipes under the ground that i cant see!!! the only thing is i just thought it a coincidence that the minute i get one problem fixed another problem arises. Do you know why one radiator in my house is not working n all the others are. even the 2 pipes leading to the radiator stone cold. Also someone told me to bleed all the radiators as there may be air in the system causing the pressure to drop. last question, is there any other way of fixing leaks without tearing my house up?

Thanks again for your help

[NJ Trooper]

If one radiator is cold, the problem is most likely that there is air in those pipes blocking the flow of water. This is where I would start to look for a leak...

But air in the system will not cause the pressure to drop like that.

I have heard of some fellows using air pressure on the system to find leaks. I think what they do is let all the water out and then pressurize the pipes with air and go around and LISTEN and see if they can hear the air coming out. I can't say if it works or not, and I have only heard this story one time...

Can you get under the house and see the pipes? Or are they out of view in the walls and floor? and you said 'under the ground'... are some pipes buried?

[smg086]

thanks again , no unfortunately, i cannot get under house n yea pipes in floor etc out of view!! i might get someone to look around this cold radiator, i did feel the connections around it and there is tiny drips (very tiny) when i rub its a bit wet! so maybe this is close to my problem.

Also did i mention, lets say the water pressure is at even 0.1 and i turn on the heating, it will within a few minutes be up at 2) - does this have any significance

god i wish i knew bout plumbing lol

thanks again

[cheinemann]

Well, the fact that you gain pressure when the boiler runs is normal. Water gets hot, then expands, therefore creating more pressure. How old is this boiler unit? I did a little research on this brand of boiler, and the pressure is measured in bar???? According to the research that I found, it states that "normal opereating pressure" would be anywhere between 0.5 and 1.5. Again, it should be at lower pressure when cold. Finally, these units look pretty nice, and not to mention they look like they could be quite expensive!

[smg086]

my boiler is approx 9 yrs old! And yes they are pretty expensive (about 1300 euro)

Can you please tell me this, i noticed one of my radiators - the fitting that joins the top part of the radiator is leaking, now its not really bad, just tiny drips really, do u think this would cause the pressure on my boiler to drop. (mine can drop to zero in matter of 3 hours somettime!!!!! this pressure drop is driving me mad especially when there is no obvious leaks except for this little leak on one of my radiators.

thanks again

[furd]

A large change in pressure is indicative of too little expansion room in the expansion tank. If you have a non-diaphragm expansion tank then it is probably waterlogged. If you have a diaphragm type expansion tank it has either lost its air cushion or the diaphragm is damaged. In either case a small leak may be all it takes to reduce the pressure to zero in a few hours.

[Mike Speed 30]

Originally Posted by smg086

Also did i mention, lets say the water pressure is at even 0.1 and i turn on the heating, it will within a few minutes be up at 2) - does this have any significance

If the gauge reads in bar, then 2 = 29 psig. More evidence that your expansion tank has lost its cushion.

[NJ Trooper]

I didn't find the exact model, but the manual for the 14e says that the relief valve is set up for THREE bar, which is almost 45 PSI I think... TWO bar might not be abnormal...

OK, read some more of the manual... your "Expansion Vessel" is to be precharged to 0.8 Bar, and the normal operating pressure should be 1.5 bar.

It does sound as though your expansion vessel has lost it's precharge. Looking at the manual, it seems that it is very difficult to get to, and that you may even have to remove the boiler from the wall in order to do so. They even suggest in the manual that since it is such a difficult job, instead of replacing the one that's in the boiler, to mount a separate one externally.

It is very possible that if your expansion tank has developed a problem it is the reason that you are losing water. It would be going down a drain from the pressure relief valve though, and not actually 'leaking' somewhere.

Even small leaks need to be fixed, whether or not they are the cause of the problem you are currently having. A constant influx of fresh water can cause mineral buildup and clog the heat exchanger passages, etc...

[cheinemann]

Even small leaks need to be fixed, whether or not they are the cause of the problem you are currently having. A constant influx of fresh water can cause mineral buildup and clog the heat exchanger passages, etc...

The oxygen contents of the fresh water being constantly added will also have an effect on this as well, and its not a good one.