Blending valves on a open vented cylinder...

[blakeecotec]

What I meant was, the vented cylinders are unlikely to explode as someone had suggested as the cold feed will release the expansion. Agreed, it is very wrong to block the vent with a hot water tempering valve. The vent pipe should be made of copper and should rise continuously to the highest point over the cistern and be no less than 19mm and have no valve fitted to it. An offset should be included, close to its point of connection to the cylinder to reduce parasitic (one pipe) circulation and loss of heat in the vent pipe. The minimum offset recommended is 450mm. -- Nuff said, but many people still get this basic stuff wrong.

 

[chris watkins]

Yes I know it is so easy to get things wrong, its holding your hands up, that is the most difficult it would seem for people now days, don't who think ??
By the way, whats the worry about parasitic circulation now days, when the pipes have to insulated for at least one Metre?
God I love Plumbing don't you ? just when you think you have cracked it some bar steward moves the goal posts. bummer !!!