Regular pressure drops in central heating

[tally100]

getting regular pressure drops in central heating, it dropped today from 1.7 bar to 0.2
i have checked for water leaks but not found any . this happens about once a month. We had a new boiler about 10 months ago and started 3 months ago.

With no leaks anybody an idea whats going on

Thanks

 

[Newboy]

What pressure are you setting the system to when cold?

Possibly at the PRV is operating if you've got the system over-pressured. It may be that the PRV has operated at some point and failed to seat again and/or the expansion vessel may need to be checked.

 

[PrenticeBoyofDerry]

Is the boiler dumping water out through the expansion/blow off?

 

[tally100]

When cold i set it at approx 1.3 bar, no water coming out of prv

 

[PrenticeBoyofDerry]

Have you checked expansion vessel

 

[tally100]

no, do i just check that is git pressure or does it need to be set at a certain pressure.

 

[tally100]

I had some new radiators fitted before christmas could that have affected the expansion vessel

 

[PrenticeBoyofDerry]

The ex-vessel should be factory set. I am wondering if this is faulty, if so you need to go back to the installer, who then contact manufacturer.

 

[PrenticeBoyofDerry]

I had some new radiators fitted before christmas could that have affected the expansion vessel

And were there any pressure drops prior to these being installed?
if not you need to investigate the valves and newly connected pipe work.

 

[tally100]

no pressure drops between April ( new boiler) and new rads fitted in Dec, definitely no water loss on any pipework no stains in ceiling no evidence of a leak.

 

[BigSnoopy01]

Turn boiler off, put pressure up to 2bar and turn flow and return isolators off. if it drops over the day its a boiler issue so call your installer, if no drop open valves, if it then drops its the system.

 

[tally100]

i assume if its the system i would see evidence of a leak as it dropped from 1.2 to 0.2 that seems a lot of water

 

[BigSnoopy01]

depends on the route of pipework, construction of the building etc.

for example if you have lath and plaster ceilings or absorbant fibreglass insulation it can take ages for a leak to show, if you have plasterboard it will show alot quicker.

 

[tally100]

All plasterboard. i had a Vaillant replaced last April due to loss of water pressure, ex vessel was changed as it was full of water , prv changed and something else was changed cost 3 visits approx £300 in total . Vaillant suggested putting some sheets of paper in the boiler and we proved it was leaking inside due to all ready costing £300 i had it replaced but its started again now as said before no evidence of leaks at rads , pipes or staining plasterboard unless i take up all flooring upstairs to check pipework i don't know what to do next i can't turn off the boiler and shut the pipes for a day as it drops it once a month all at once as it did today 1.3 to 0.2 in one go.

 

[Robin37]

hi, i had a leak recently and it was dripping onto flow/return pipes and evaporating so no evidence of it anywhere.