mega flow system over pressurising daily

[dino89]

got a pressurised mega flow system which keeps over pressurissiing , for example yesterday i released the pressure on the top of the red expansion cylinder to below 1bar and this morning its back up to 2bar this has been getting steadly worse for some time i only have the hot water on at the momnet the heating hasnt been on yet this year, i have seen it go up to 3bar on a few occasions but this used to take a while but now it seems to only take a few days max
the boiler is a potterton suprema 6C L
any ideas whats going or any one in the stevenage aera able to service and repair this ?

 

[45yearsagasman]

Check that your filling loop is shut 100%. Disconnect it if its attached and cap the ends. Make sure the red exp vessel has a precharge.

 

[dino89]

thanks for quick reply,i did disconnect the fill loop and still the pressure went up i have been doing some reading and it mentions using a foot pump to charge the expansion bottle, how do i check this and carry this out correctly and what pressure should is correct for the expansion bottle thanks Dean

 

[45yearsagasman]

You will need to de pressurise your system via a drain point and then attach a pump to the schrader valve(like your car tyres) and pump it up to approx .8bar.
If by any chance water comes from the valve then the vessel will need replacing as the diaphragm will have split.

 

[dino89]

thanks will have a look the valve is on the bottom of the expansion vessel when you say depressurise is it just letting the water out the expansion bottle till it reads 0 bar or do i need to disconnect the fuill loop as well or drain the whole rad system thanks again

 

[dino89]

ok done that released pressure till 0BAR then pumped cylinder upto 6 bar bloody hard work Lol , opened fill loop till it showed 1 bar then put hot water on just checked it approx 5 hours gone by and its almost at 3 Bar
one other thing sometimes when i let the pressure out via knob on top of expansion botttle its sounds like air is bubbling out as well but not all the time , and when i put the pump on the cylinder it had less than 5psi in it and no water came out the valve

one last thing thought i would try released pressure pump pum back on to see if air was still the same and it was !

 

[45yearsagasman]

Why did you pressurise the exp vessel to 6bar!!!!! when I said .8 bar.
If it wasn't damaged before it probably is now. Pays to read the advice carefully.

 

[dino89]

didnt see a point ! just a full stop still i just released the pressuure back to .8bar and no water has come out ,if its damaged that`ll teach me to look more closely, will see how it goes but suspect this may not be the problem as it has held the air ok even if it was to high

 

[dino89]

still pressure in system is increasing on its own any more ideas on what the problem is? its going up by at least 1/2 bar a day

 

[stardanny]

If the filling loop is removed and cap off, if the heating system pressure still rising without any heating or hot water on, then sound like there's a pinhole in cylinder coil with main water passing into heating system. G3 plumber should be able to check that. Possible a new cylinder.

Dan.

 

[dino89]

thanks for the reply stardanny is that the actual mega flow cyklinder that may have the pinhole or in the boiler ?
i must say i will have to check, but feel its more when the hot water is on it seems to raise and then hold extra pressure even when its cooled back down ,

 

[stardanny]

You have a sealed system heating and main pressure hot water storage tank.

There is a test you could try below:

Turn off the water supply to megaflo cylinder.

Turn on hot water taps till it stop running.

Leave it for a day or two and check heating system pressure gauge.

If the pressure start to drop or didn't go up, there's a pinhole in cylinder coil.

Dan.

 

[Agile]

I am not at all confident that you have pressurised the EXV correctly!

Release all the air by pushing the pin in. Note if water comes out. Note what the pressure reads before and after this. Then tell us!

Then open the system to the air to release the pressure, and apply the air pressure until the gauge reads 0.9 Bar. 9 I put the leading zero to help you! ). Make sure when you have done this that the system pressure is STILL at zero. If not you have not it correctly!

Then pressurise the system to 1.5 Bar!

Whatch the system pressure as the heating warms up. It should not exceed about 1.8 Bar.

Tony Glazier

 

[dino89]

thanks for the reply tony
i have gone through your procedure and let all air out of system by pushing valve pin in, no water or moisture came out of valve at all,
now if i understood this before pushing pin in it read 1.5 bar after all air exvacuated it read zero then opened pressure please valve and pumped to 0.9 bar then used fill loop to obtain 1.5 bar in exv hope this is correct
thanks for the zero in front of the point could of done with that ealier in the post LOL
i have the pressure at 1.5 now and hot water on will keep an eye on it and post back thanks

 

[dino89]

just been up and checked pressure with heating and hot water running since last post and its risen by 0.2 bar