Heating pressure losing 0.7bar per 24 hours cycle.

Albermarle

FreeBear said:

ThisIsWeird said: Nothing wrong with plastic pipe

The fittings are big ugly things, and the inserts restrict flow even further.

Whilst it is possible to use copper on the final ~200mm to the radiators, you still need space to accommodate those ugly fittings.

They may be ugly but they are very cleverly designed !

Belenus

FreeBear said:

Belenus said:

FreeBear said:

 Personally, I'd bite the bullet and go for a replumb, fitting larger radiators (and use 15/22mm pipe) with an eye to installing a heat pump at some point in the future.

Are plastic pipes recommended now?

Our 2004 built house has mainly plastic pipework for the CH system.

Not in my book, and I'd steer well clear of Speedfit type joins... One thing to bear in mind with plastic pipe & fittings is the bore is quite a bit smaller than the equivalent copper pipe. This will restrict the volume of water that can be circulated around the system and thus the amount of heat distributed to each radiator. You can increase the pump speed to compensate, but this increases noise and places a greater strain on the pump.

House builders like plastic pipe because it is cheap and quick to install. And they don't have to worry about it lasting..

The house was built in 2004 and we bought it in 2011.

The CH pipes are about 10mm external.

There are no visible 'big ugly fittings'. They are presumably hidden in the walls and under the floorboards. The join at the radiator valves look neat to me. See picture below.

The only visible pipework is an inch or so at the radiator valves. The pipes come out of the wall behind the radiators.

We don't have any problem heating the house so presumably any restricted flow is still adequate.

ThisIsWeird

Are these pipes plastic? If so, good news, as the leak is likely to be a one-off, perhaps due to a failed (wrongly installed) fitting, or even physical damage.
So, worth tracing, digging, and fixing.