Question from Michael Heads, via e-mail:
Is it acceptable for discharge pipes from the expansion relief/pressure and temperature relief from an unvented domestic hot water system to discharge against a wall in the way a PRV valve from a sealed system can?
Answer from Martyn Bridges, director of marketing and technical support at Worcester, Bosch Group:
It is not permissible to terminate the discharge pipe from an expansion valve or from a temperature and pressure relief valve in this way. I would advise consulting Part G of the current Building Regulations, which lists the accepted termination positions, as they are too numerous to mention in this response.