DHW Cylinder - Vent pipe question

[Mr Mobius]

I have a question with regards to the vent pipe on this cylinder. From the top of the cylinder it will rise vertical for 1.6 M then it will have about a 30 degree bend for 2.2 M before being position above the cold water storage tank.

Generally I have always just installed the vent vertical with no angles or change in direction untill above the tank.

Anybody see a problem with this design.

Here is a diagram to help understand the proposed changes.

 

[GQuigley67]

Can't see why it wouldn't work as it is just for expansion

 

[gassafe]

I reckon it will work a treat! Just remem to lag it all the way =]
Some of the vents pipes iv seen have taken a right hellish route before reaching the roof tanks...

 

[Bernie2]

Err! Nothing wrong with the idea except if I remember right there is something somewhere about running pipes so close to the under surface of a roof tile. As usualI have forgotten where I read it. Possibly Water Regs. I think it has to be a certain distance away to avoid freezing up.

I will try to find the info, but then all it will mean if I am right is running the pipe level across the loft and rising just before the tank.🙂🙂🙂

 

[Mr Mobius]

I have attached a link which highlights some important points on such an installation...

[DLMURL]http://www.ciphe.org.uk/Global/Databyte/Cistern%20Installation.pdf[/DLMURL]

 

[stevetheplumber]

all vents are supposed to turn after it leaves the cylinder to stop parasitic circulation this is where the cold outer part of the pipe causes a thermosyphon action ie cold outer drops hot center rises however i do feel this is a throwback to the days of solid fuel and cold houses thats never been challenged with lagging and warm house these days ive never seen it happen

 

[Mr Mobius]

Yes I suppose I ought to have added that the pipe work from the top of the cylinder will rise vertical 150mm to a pulled bend and then 450mm horizontal to avoid parasitic circulation 'then into the T'eed position in the diagram as shown above.

But a valid point Steve.