temperature/pressure relief pipe over flat roof

[chimbs]

I have had a flat roof extension built to the rear of my house. The system boiler is in the loft and the temperature/pressure relief pipework now projects over the flat roof. I have concerns that any hot water discharged will damage the felt and so would like to reroute. However this would mean a long run of approximately 12metres including several swept bends ! If I was to do this in 22mm copper would this be acceptable?

 

[kirkgas]

potentially under fault conditiions the water temp will be about 85 degrees, surely this wont damage felt? i appreciate if it continued to discharge very hot water over a long period onto the same bit of felt it might, but it isnt likely, re-routing is possible, but would need to be done properly because any water freezing in the pipe will cause more damage to the boiler than the hot water will cause to the felt, TBH, if it was my house i would leave it

 

[chimbs]

Thanks Kirkgas !Yes - probably slightly paranoid but would be happier rerouting. There will be no danger of freezing because it will be running most of the distance with a fall inside the loftspace and have a vertical drop through the soffit for the last 2metres . I know that there won`t be a huge amount of system water but just wondering whether 22mm will cope.

 

[sooey]

You say it's the temperature/pressure relief pipework, have you got an unvented cylinder up there as well?

 

[chimbs]

Hello soey - no just a vaillant ecomax system boiler

 

[sooey]

You're 22mm should be well big enough then. there wouldn't be that much water comes out before the prv shuts
Though it can still freeze in the loft space, I'm with Kirk, I'd leave it as it is.

 

[chimbs]

Thanks for your advise guys - I will leave it!!