Hot water going up the vent pipe

[petit_pablo]

Could I not just replace the T in the 15mm pipe with an elbow to take the return straight back down? Then bring the cold water feed round and T into the horizontal pipe below the pump? Any chances of a pic of the H layout?

Yes you can, its probably what i would do.

Also the 15mm return from the cylinder - will that be a problem or is that fine to be like that?[/quote]

Thats fine, quite normal to find 15mm return from cylinder. It restricts the flow in a similar way to how a balancing vlave would

 

[sotal]

Thanks for the reply - I think I'm getting there now.

What is the 15mm pipe balancing with, espicially when there is only heating on, on it's own? If it restricts the flow - where does the rest go?

 

[petit_pablo]

Thanks for the reply - I think I'm getting there now.

What is the 15mm pipe balancing with, espicially when there is only heating on, on it's own? If it restricts the flow - where does the rest go?

All the 15mm is doing is slowing the flow down through the cylinder to maximise heat transfer. The common return to the boiler will be in 22mm

 

[sotal]

Am I right though that when the hw is on, on it's own that all the flow from boiler has to go through the cylinder and then through the 15mm before returning to the 22mm pipe at some point? Wouldn't that have the effect of restricting the flow?

Also how far should the 15mm pipe run for? It seems to go as far as I can see

 

[petit_pablo]

Am I right though that when the hw is on, on it's own that all the flow from boiler has to go through the cylinder and then through the 15mm before returning to the 22mm pipe at some point? Wouldn't that have the effect of restricting the flow?

Also how far should the 15mm pipe run for? It seems to go as far as I can see

Thats exactly what it does and why its there.

I would imagine the 15mm runs to where it tee's back into the return from the ch

 

[heatingman]

Sorry for delay, been bouncing about.

 

[sotal]

Thanks for the help, we took the slightly easier option of just re-routing the 15mm feed to come into the flow pipe after the vent but before the pump.

We also removed the bleed pipe from above the pump.


All seems to be working well now with no hot water going up the vent or the feed.


Thanks again