On Friday, 18 December 2015 16:02:57 UTC, Richardmerri wrote:
Hello all... Can anyone advise me on how to remove the large tapering red knob on the PRV? I spoke with a Baxi employee who told me that the red knob could be removed easily to reveal the seal and seating which may need a clean... I cannot fathom any way of removing it! It is quite loose until about 1/3 of a turn anticlockwise when it appears to engage the spring mechanism... We are loosing pressure over a few days. Any help would be greatly appreciated...

It could also be your pressure vessel diaphragm has ruptured if you are losing pressure in your system and having to keep topping up.

In which case the relief valve is doing it's job.