Boiler pressure between 3.5 and 4

[isazm]

Hi! Would really appreciate some help on this..

I got a 24c glow worm, and the water pressure has been at 3.5 cold and 4 when hot. I read around and seems that mains is open on the internal loop, but i cant seem to close the mains. here are some photos

thats the boiler with the pressure

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• isazm
• 24 Apr 2015
• 1

and under the boiler there is this loop, but seems to have no valves on it?

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• isazm
• 24 Apr 2015
• 1

and even below this, i found this, not sure if it's relevant but thought I would include the whole system.

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• isazm
• 24 Apr 2015
• 1

Thanks a lot!

 

[oldbuffer]

The filling loop is the silver coloured braided hose in your second photograph.

One end of this (or preferably both) should have a valve fitted. Most likely one with a screwdriver slot. If the slot is parallel with the pipe work, then it is open. If the slot is at right angles to ("across") the pipe, the valve is closed. It's also possible the valve once had a small plastic handle which has been removed. If this is the case it will have a circular protuberance with flattened sides. For on / off treat the flattened sides as if they were screwdriver slots as above. Any hexagon headed "nut" on the side of the valves / pipework is a non-return valve and should not be touched, unless you fancy a flood.

If the valve(s) is / are open, close it, open a radiator bleed point and let water out then close bleed point. The correct pressure is usually around 1.2 bar. If you let out too much, close radiator bleed point then open filling loop valve for a few seconds at a time until gauge reads 1.2 bar. Note all the above should be done with everything cold.

If this doesn't do it, then there may be a fault with expansion vessel within the boiler, for which you'll need a Gas Safe Registered engineer. In any even, water will have been running through your system and out of the pressure relief pipe to outside. This means you are likely to have little or no inhibitor in the system and this should be replenished. Again I'd suggest you get an engineer to do this. If its not done there is a risk of radiators rusting from the inside out.

 

[isazm]

Thanks a lot for your help.

Here is a closeup of the loop, would these 2 slots be valves?

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• isazm
• 24 Apr 2015
• 1

 

[oldbuffer]

In your latest photograph, the valve on the right (circular with two flat sides) is the spindle of valve you need. It would have had a handle when new, but as stated earlier these are sometimes removed. It looks as if is is very slightly open, but very hard to tell from the photograph.

You'll need a small spanner or a pair of pliers to turn the valve. Turn it so that the flats are completely at right angles to ("across") the valve body and this should turn the valve off. Then proceed as advised above.

Before turning the valve off you may be able to see dripping from the copper pipe outside the room. After turning off and reducing pressure, this dripping should stop (give it ten minutes or so). If it still drips, then an internal boiler valve called the pressure release valve (PRV) may have stuck - they often do after being activated.

If this is the case then you'll need to get it replaced by a boiler engineer. They are a safety device, and normally relieve the pressure when it reaches 3 bar, so it would be sensible to get your's replaced anyway as its going to 4 bar.

 

[isazm]

Thank you so much for the explanation.. I have never worked with gas boilers before, back home I had diesel. This has been enlightening. I will be getting an engineer to change the relieve valve and have them go over the whole thing.