Not that you would notice. But I want to disconnect it not just to eliminate the possiblity of it letting by but to stop someone messing with it. I suspect the heat exchanger. Pressure creeping up slowly when switched off.Is it passing or do you just want to disconnect it?
There is a spare loop on the market. No taps. Just doesn't give you any details about the threads. I just thought one of you guys might be familiar.1. If its a standard filling loop, any 1/2" BSP end cap will do. E.g. Screwfix 51939. Make sure it has rubber or fibre sealing washer inside.
2. If its the Vaillant built in one with two grey plastic handles, you would need to measure the threads (diameter, thread pitch) to stand any chance, as I don't think Vaillant list anything suitable as spares.
Reply to the thread, titled "Vaillant ecoTec Plus 831 Filling Loop End Caps" which is posted in UK Plumbers Forums on Electricians Forums.