I cant seem to get it into my thick head atm if there is a differance between these two. they both basically in the event of trv's closing down the system allow the hot water to dissipate from the boiler via the flow and return. Automatic i assume means the valve will simply open when this is required while a differential will adjust itself depending on the flow . is this correct ?. If not could someome please clarify for me.
Thank you,
Thank you,