OK, I did miss that (familiarity etc). It's just the way the system has been drawn. The blue pipes are returns. In real life, the cylinder return (left one) is connected into the heating return; so only one pipe actually goes to the boiler.Sorry I am missing something here, I was looking at the same plan. I can see three pipes leaving the boiler two cold ( blue ) and one hot ( red ).
That's quite normal. The 15mm cold water fed from the expansion tank feeds into the flow from the boiler just before the pump. You may also find a second 22mm pipe, about 150mm from the feed pipe. This is the vent pipe which hangs over the expansion tank. Some systems combine the feed and vent pipe, if so it will be 22mm.Incidently in my system the pump is next to the HW cylinder and is fed by the expansion tank in the attic ( I think, pipe certainly goes into the attic where tank is ). The pump then feeds the two MVs which T off to HW and CH.
Please post back to this topic. Then we won't have to scrach our heads wondering what you are talking about.Will let you know how I got on but might not be for a couple of weeks yet.
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