Joule Invacyl Unvented 150L Indirect Cylinder Standard Stainless Steel. The Joule Invacyl Unvented 150L Indirect Standard Cylinder has a sleek grey outer case and is manufactured to the highest standards making it the UKs’ number one cylinder brand. Invacyl Unvented 150L Indirect Cylinder Features. Invacyl Standard Unvented Indirect Information Sheet. Weight – empty 38KG, full 184KG. Heat up time 36 minutes. Test pressure 10 Bar. Pressure reducing valve 3 Bar. Polyurethane foam CFC-Free and HCFC Free. Cylinder Material – Stainless Steel Duplex. What Do You Get In The Box? 1 x Invacyl Standard Unvented cylinder. 1 x 3KW Incoloy immersion heater. Temperature and Pressure Valve. Hi Limit Cut Out Stat. 2 Zone Moterised Valve. Built on quality and performance, with one of the widest ranges of models available you can be sure there is a model to suit.