Pressure relief pipe from boiler?

[cole46]

I have to fit a std efficiency system boiler to a u duct and an unvented cylinder. Can i connnect the pressure relief pipe from the boiler to the plastic overflow relief pipe from the cylinder with another tundish?

 

[Boilerman2]

Technically the boiler discharge should be separate from the unvented discharge arrangement, but yours sounds a difficult install are you sure that the plastic drain from the unvented cylinder will be able to withstand scalding hot water??

 

[cole46]

Hi thanks for your reply boilerman. I know that it would be better seperate but I have seen this done on a Keston boiler installation and a colleague has said he has seen one too. As you say an alternative route has many problems.