Doe anyone know the statutory examination requirements for pressurised unvented hot water systems. My own feeling is that if the capacity of the pressurised hot water tank multiplied by the pressure gives a prodcut of 250 bar litres or more than it must be examined. I cannot find anything to confirm this and the PSSR does not specify if hot water systems are included.

Thanks for your advice Peter.

Yes, I think it does fall within the requirement for a statutory examination except that it depends whether the water in the systems is a "relevant fluid". 

According to the HSE a relevant fluid is: 

• steam at any pressure
• compressed or liquefied gas, including air, at a pressure greater than 0.5 bar above atmospheric pressure; pressurised hot water above 110 °C
• a gas dissolved under pressure in a solvent (acetylene)

So I think I have found the answer to my particular problem. The client is a nursing home so the water in the system will be below boiling point and is therefore exempt from the requirement for a statutory examination.