I've just drained the system to fit a new diverter valve to my Vaillant VCW-sine 18 T3WF H, plus changed some old TRVs as well.
Is there any reason not to add inhibitor when I top it back up? The manual makes no mention of adding it, and I've heard older boilers don't like it.
I'm pretty sure there hasn't been any in there for years and when i drained it the water was a bit black, but all rads seem to work fine.
Is there any reason not to add inhibitor when I top it back up? The manual makes no mention of adding it, and I've heard older boilers don't like it.
I'm pretty sure there hasn't been any in there for years and when i drained it the water was a bit black, but all rads seem to work fine.