Pressure testing system - lost 0.2bar over 7 days

[Deansplit]

Is this usual? It's a fairly large system (not sure on exact litres but it's a 3 story home - 2 reception rooms, 5 beds, office, large living rm, attic, but kitchen is UFH).

I've basically replaced copper for plastic and rerouted/added a few rads whilst restoring the Victorian property. After an initial few leaks (mainly from TRV's which don't fully switch off!! Grrr), I refilled to 4.5bar, but since last Friday, it's dropped by 0.2 but no sign of any leaks.

I've been told the water itself will compress and release oxygen which in itself will drop the pressure in a newly filled system. I need to get the plumber in to connect the new condenser boiler but 'if' there's a leak I want it fixed before having him looking for it on a daily rate basis - which presumably he'll not be any the wiser than me as there are no signs anyway!?

Any help appreciated

Thanks

 

[Boilerman2]

The pressure will Fall or Rise on Temperature change during test!!
0.2Bar in 7days sounds absolutely minimal to me!

 

[bengasman]

Is this usual?

No. It is possible that here was some air in the system, but once a system is bled, it should not lose any pressure.

 

[Deansplit]

I topped up the system to 4.5bar and shut of supply. The next day it was now '+'0.2!! How can this happen?... dodgy gauge?

 

[Agile]

When you pressurise a system so high there will be changes in pressure over a few days.

Most commonly there is a slight reduction in pressure as the nitrogen in the remaining air slowly dissolves in the water.

This is all normal and only to be expected.

The plastic pipe you have used also will increase its volume when you apply a pressure exceeding its normal operating pressure.

So you have nothing to worry about!

Tony Glazier

 

[Deansplit]

Thanks Tony, knew my handy work wouldn't let me down!!

 

[Agile]

I would normally look to replace plastic with copper rather than the other way round!

 

[Deansplit]

Hi Agile
Some of the TRV's I put on the system still leak when fully off, (I posted a thread on 22nd but not really any the wiser! Hoping you can help...?) so I've had to add a piece of pipe with a stop end to fill the system. Is this normal, cos that tells me they'll waste H/W when all up and running when you want rads off?? I've not tried the decorators caps as someone suggested as it's irrelevant as it won't be those which will be on the finished rads!

 

[Deansplit]

I would normally look to replace plastic with copper rather than the other way round!

Read more: http://www.diynot.com/forums/plumbi...bar-over-7-days.288567/#2104630#ixzz1XA5RxDgS

...not if you live in Newcastle Co Down - well known for something in the water called 'Newcastle disease'... pin prick holes start to appear, pipes full of black cr@p inside, heard so many people who have suffered major damage.