Boiler pressure issue

[ashtonjay]

Im currently doing a bathroom for a customer
he had a boiler fitted recently and i put in his new 9 rads and pressured it up to 1.5 bar bled air etc etc
we had the heating on whilst we were working as house is empty and bloody freezing
we have had it on 2 days now but notice each morning the pressure gauge is back down to zero and it needs pressure again
i always put the stopcock off before i leave the house at night and back on in the morning

cant see any visible leaks above or under floor either can anybody assist?
cheers

its a Woscester boiler for what its worth

 

[Whn1]

What does the pressure go upto when Its hot?

 

[Gray0689]

Expansion may be gone
Safety valve may be passing if its a combi hex may be leaking
Or could just be a leak you haven't seen yet

 

[ashtonjay]

when its hot it stays at 1.5 bar
cant see any leaks
its a brand new boiler he had fitted about 2 weeks ago

 

[kimbo]

If there is still air in system AAV may be letting air out and so losing pressure, also as Gray says

 

[Centralheatking]

9 new radiators ! so how many rads on the system in total..it seems to me
that maybe the exp vessel on the combi is too small to cope and you need
more exp capacity. Are you registerd to work on heating boilers - otherwise
the mods onhere will move this post on.......centralheatking

Im currently doing a bathroom for a customer
he had a boiler fitted recently and i put in his new 9 rads and pressured it up to 1.5 bar bled air etc etc
we had the heating on whilst we were working as house is empty and bloody freezing
we have had it on 2 days now but notice each morning the pressure gauge is back down to zero and it needs pressure again
i always put the stopcock off before i leave the house at night and back on in the morning

cant see any visible leaks above or under floor either can anybody assist?
cheers

its a Woscester boiler for what its worth

 

[ashtonjay]

9 new radiators ! so how many rads on the system in total..it seems to me
that maybe the exp vessel on the combi is too small to cope and you need
more exp capacity. Are you registerd to work on heating boilers - otherwise
the mods onhere will move this post on.......centralheatking

no im not gas safe and never touch boilers at all except to pressure up a system
ill check the little black screw on the top of the AAV tomorrow just in case its losing pressure that way

cheers