0.4 bar pressure drop on testing underfloor heating

[Adman101]

Hi,

I have laid underfloor heating in my extension and I am testing it. I attached a Monument water pressure gauge at 5pm last night which showed 5.3 bar and noticed when i got back from work today the gauge is showing 4.9 bar - 24hrs later. this is obviously not good but I wanted to rule out a few things first. Is the gauge likely to be dodgy? It was a tenner so isn't going to be of good quality but should still be reasonable reliable??? There are no obvious leaks in the pipe work and all of the connections to the manifold are dry. Could there be air in the system which is being squeezed out somewhere? I have the screeder coming on Monday so want to make sure there is nothing serious.
Any advice would be great.
Thanks in advance
Adam

 

[footprints]

Could be temperature change, water cooling and contracting, I would leave it another 24 hours now it has stabilized before getting too worried.

 

[Aquaheat]

As above I would allow for temp changes that will affect pressure and a bit of air in there too. You'll know if there is a drop as it will tend to be a constant. Had one where it was sitting at 10 bar until they screeded and it dropped to 6.5 after. All due to the cooling effect of the screed. One did drop to 0 but that was because the labourer put his spade through it. That wasn't a funny couple of hours! It should be fine though mate, just give it a couple of days to settle. You'll know if it's leaking.

 

[Adman101]

I had a bit more of a drop tonight, but I run my finger over everything to check for wet and noticed that one of the large isolation valves that goes fromt he manifold to the pump had the tiniest bit of water on it. I don't think that amount of water would contribute to that amount of pressure drop but still it needs tightening - quite a tricky task with everything connected to it, any suggestions?

 

[muggles]

Depressurise, tighten the weeping joint and repressurise