pressure dropping

Rhodes7373 · 26 Sep 2009

Hi All,
I live in a ground floor flat with the central heating pipes running under the flooring..... you know where this is going! anyway i top the boiler up and within 10 mins the pressure drops from 1 bar to 0.

This would indicate to me a leak somewhere.

The bathroom is currently being redone, and after a tile fell on one of the pipe i had to cap both pipes that feed the radiators on the other half of the flat.
So only 3 radiators are currently active, the loop is not leaking, i have taken up the floor boards and the where the 10mm pipe meets the 15mm pipes, i can't see any leaks.
All the pipes are off ground apart from where the main two go through the wall (15mm) to feed the 3 radiators which spear off of the main 15mm.
I can't see any sign of water anywhere, but im guessing that after topping the water up 5 or 6 times trying to find the leak, i would have spotted something.

So... im at my whits end trying to track this down, any help would be great help.
Could it be the boiler? the pressure does not rise when turned on, just the slow loss of pressure.

cheers

Neil

mickyg · 26 Sep 2009

What boiler is it? have you checked outside where the pressure relief pipe goes?

Rhodes7373 · 26 Sep 2009

thanks for the swift response, the boiler is a ravenheat CSI 85 BT.
I couldn't see anything leaking out when i looked, and im guessing that it would be quite a lot?
When i do top the boiler up the pipes at the top do hiss, as if pressure is being released??

mickyg · 26 Sep 2009

but have you seen where the relief pipe goes? It usually comes through the wall in a 15mm copper pipe with an open end, ideally turned back to the wall. It exits from your boiler I think, furthest to the right. So you should see it come out the boiler and dissapear through the wall

Rhodes7373 · 26 Sep 2009

just checked the pipe and they is water dripping from it

Rhodes7373 · 26 Sep 2009

hi micky the boiler is on the wall in the kitched, there appears to be two pipes coming out the wall the other side.
One is plastic 15 mm pipe which goes into the drain, the other is a copper 15 mm pipe that is just open and appears to be cut off about 4 ft from the ground.
So im guessing that they have swapped the old copper one with a plastic one when the boiler was replaced 18 months ago?
The plastic pipe has a slow drip coming from it, when i top the boiler up

kevplumb · 26 Sep 2009

One is plastic 15 mm pipe which goes into the drain

condense drain

the other is a copper 15 mm pipe that is just open and appears to be cut off about 4 ft from the ground.

prv pipe

the white one should drip when the boiler is running the copper one shouldnt

Rhodes7373 · 29 Sep 2009

its the plastic one thats dripping.....

....Could it be a problem with the boiler or with the speed of the pressure dropping, has it got to be a leak?

kevplumb · 29 Sep 2009

neilgilbert1234 said:
its the plastic one thats dripping.....

....Could it be a problem with the boiler or with the speed of the pressure dropping, has it got to be a leak?

if its dripping with the boiler off and cold then its a prob with the boiler

BingoBongo · 29 Sep 2009

tie a small plastic bag around the prv for a day to check

is there any signs of corrosion under the boiler.the iso valves or auto air vent could be leaking

check and double check the rad valves including the packing nut on the lockshields,

is there any staining on the pipes at the rads?

does the pressure on the boiler rise to 3bar when heating is on?

find the drain valve as they can also pass

powell30 · 29 Sep 2009

If it's dripping from the condensate with boiler off then the main heat ex is leaking. Easiest way to check if its pipework or boiler is to turn off all iso valves beneath after you have filled it to a set mark....say 1.5 bar.....if pressure drops its boiler if not it's pipework. If it is the prv then it might need changing or cleaning but if the water is running out of the cendense then it has to be the heat ext gone.......big job lots of money....

gassafeman · 29 Sep 2009

Agree Powell. Known many weeps on the Heat EX drying up due to the heat inside the boiler.

Paul

Rhodes7373 · 30 Sep 2009

ok first, i have to say thanks for everyones help with this.....

.....I topped up the CH today and then closed all the ISO valves... and the boiler held the water pressure.... so hopefully that means the boiler is ok.

... when i was topping up i could here a hissing/release of air coming from the pipes next to the boiler which go off to feed the heating.... but these have been boxed in!?

powell30 · 30 Sep 2009

It does......but it may still have a doggy prv and you need to trace the pipework leak. Just call a professional in....it will be easier.

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pressure dropping

gassafeman

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