Leak detection using a pressure guage

[davidb]

Hi

I had a leak (now fixed) but the drying company says there is another leak (the floor showed damp after they removed their equipment). Of course they may be right ... but maybe it just needed longer to dry out.

So I got a pressure guage ... with the stopcock open it reads 2.6 bar. 30 minutes after closing the stopcock it still reads 2.6 bar ... so I'm thinking no leak.

BUT 12 or so hours later the pressure has droipped to 1 bar. So now I'm wondering is there a very slow leak ... or some other explanation??

Any ideas?

Thanks

David

 

[SimonJohns]

I would say you have a slow leak

Isolate as many parts as you can to narrow down which part of the pipework is leaking

 

[Howsie]

Could also be a leaking tap/stopcock/FOV.

 

[davidb]

Good suggestion thanks ... I did isolate the downstairs toilet for this very reason (I could hear rhe drip in the cistern) ... but I'll check the upstairs one etc.

 

[leelister6]

once spent 6 hours looking for a leak in a ceiling. Could see the water dripping down but for the life of me couldn't find where it was coming from. more by luck than judgement, found a pinhole in a pipe 6 feet away spraying onto the other pipework. Looked like a spider web cos the jet was so fine!

 

[diamondgas]

You could well be looking for a teenyweeny tiny miniscule of a leak IMO! If you have no airlocks anywhere then it doesn't take much water leakage to drop the presure 1.6Bar! Could well have been the pipes cooling down even? Just a thought

 

[davidb]

diamondgas I'm liking your thinking .... just to expand the question slightly ... with a combi can I asume 'open circuit' between hot and cold or is there a valve in the way. Reason for asking is the hot pipes were full of hot water when I took the first reading ... so that cooling down will reduce pressure in the hot circuit I assume .. would it also reduce pressure in the cold circuit?

 

[diamondgas]

diamondgas I'm liking your thinking .... just to expand the question slightly ... with a combi can I asume 'open circuit' between hot and cold or is there a valve in the way. Reason for asking is the hot pipes were full of hot water when I took the first reading ... so that cooling down will reduce pressure in the hot circuit I assume .. would it also reduce pressure in the cold circuit?

Usually open circuit davidb ... I say usually because some folk may have had a none return valve fitted to stop nuisance on/off issues caused by trapped air in the domestic circuit. It can be as little as a thimble full of water loss to drop the pressure to zero!

Try it, turn your main water isolation valve off and catch the water when you open a tap. That'll give you an idea of the quantity of water you're looking for.