22 mm hot water pipe comes from the boiler and is teed up for the cold
feed with 22mm pipe. The there is a Pump and it is further teed up with 15 mm for by-pass which it seems an isolator connected to Return.
The hot water has mid-position valve. One side goes to immersion tank and this has auto air trap bottle. The other side goes to heating and that is
also teed up with 15 mm and some thing like end cap with a screw in the middle is soldered on. I suppose this is used to bleed air out on heating side. Bottle air trap is used the let the air out from the hot water side.
But definitely there is not vent pipe.
Very common DIA surprises me you have never seen it , have a look at www.partsarena.com/baxi bring up the myson economist 30b/40b or thorn apollo 15/30si and they have a couple of different ways of doing it
Dave this was not brought in by BG it was manufacturers
As you mentioned thorn appolo 15/30si that reminds me the boiler that
was replaced was indeed thorn appolo 15/30 si. This also vindicates the reason that there was no vent pipe. But as now I have got vaillant and the
manual mention a vent pipe:
Should I put one or leave it as it is?
This system also has bottle air trap and another end cap with a screw to
bleed out air.
I beginning to think that I should leave it as it is and replace the auto by pass as it has a service valve type.
Could you advise?
I appreciate all of you for your replies and suggestions
if its a new install then get the guy who fitted it round to get it up to spec,as for bypass. gate valve was the one, before the auto bypass but a service valve is a bit much.
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