probs-probs-probs!

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Can anyone help please???
I seem to be constantly up and down the stairs topping up my 'sealed' heating system!
I have a 18 month old system consisting of a Glow worm micron 30ff boiler and 10 radiators around the house.
I spotted a leak outside about 2 weeks ago and was told to replace the 'RED' capped pressure relief valve, which i did and then i bled the system keeping the pressure at 0.7 BAR. all this done and the pressure still drops over time but more importantly the pressure goes up to 3.0BAR and above sometimes?? this activates the pressure relief valve???
Why does it go up so high??
is there a special way to bleed 'sealed' systems??
What should the max pressure get up to??
Can i have a whole day without worrying about being woken up by air in the system?

Please help as it is driving us both mad??
Thanks in anticipation.
 
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You may have two seperate problems :cry: the first is a leak somewhere, the second seems to be a defective expansion vessel or a blocked feed to it. There is lots on EV's via search.
 
Thanks for the reply. ONE small question HOW do i check the EV?? is it easy?? :confused:
 
i have noticed that the pressure guage on the boiler goes from 0.7 Bar (Once i have put more water in) to over 3.0 bar in a matter of 10-15 minutes when it is running????

also the pressure drops from 0.7 bar to 0.4 bar when you fire up the heating and/or the hot water together.

does anyone know what is wrong and how to check it so that a diffinitive answer is possible?

all help will be greatly appreciated.
 
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Why does it go up so high??
Classic symptom of an expansion vessel in need of some TLC or replacement. The EV contains air to compensate for the expansion of water when the temperature rises. If there is insufficient air in the EV the water will pressurise the system and once it hits 3bar will vent off through the pressure relief valve.
there a special way to bleed 'sealed' systems??
No, just do it the normal way and then top up the pressure at the boiler once you've finished.
What should the max pressure get up to??
You normally pressurise the system to 1 bar (cold). It should stay pretty constant if everything is set up OK. 1.5bar max.
worrying about being woken up by air in the system?
Problems with the EV will just cause a loss of pressure in the system as you lose water when it heats up. However, this doesn't cause air to get into the system, If you have this as well then that sounds like another problem.
ONE small question HOW do i check the EV??
If you have a manual it should show you where the schrader valve is, if you have one (car tyre valve) press the centre plunger. If air comes out then "all you have to do" is re-pressurise the EV. If water comes out the EV is broken.
 
:eek: Thank you so much for the reply you posted. I have just checked and there isn't a schrader valve in/on the EV. Do you know if there are any other ways of checking the EV without one? Getting a feeling that this problem could cost me dear!! Appreciate your help very much and thanks again.
 
Problems with the EV will just cause a loss of pressure in the system as you lose water when it heats up. However, this doesn't cause air to get into the system, If you have this as well then that sounds like another problem

If the lack of expansion capacity (broken diaphragm, blocked pipe, ...) is causing the system to lose significant amount of water out of the discharge pipe, when everything has cooled down, the remaining pressure may be close to zero. Depending on the plumbing, if the system is started WITHOUT first repressurising it, the pump will cause a pressure DROP in parts of the system that might allow air to be sucked in. So maybe only one problem.

As an emergency measure, leave some air in some of the rads (ie. don't bleed them) - this will provide some expansion capacity until you can get the system fixed properly.
 
Thanks for the replies. The expansion vessel is located between the boiler and the wall so is not very accessible!! There is only 1 pipe going into it at the top in the middle. I have given up with bleeding the radiators but have noticed that the air seems to accumulate in the upstairs landing radiator even though this is lower than the tank etc in the airing cupboard. The automatic bleed valve in the airing cupboard also leaks a tiny amount of water out of the top vent piece, is this normal? It isn't problematic and doesn't spill over but may be another clue to the problem. Thanks again for all the replies and help.
 

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