Ok, so the gauge that was recommended arrived today in the post.
I turned the stopcock off but everytime I tried to take the grey cap off the prv water kept spurting out. I never took the cap off completely as each time I loosened it water was coming out under pressure.
The mains pipe comes up through the floor and then goes all the way up to the thermal store in the loft. So I presume this volume of water sitting in the pipe work above the prv will pour out if I take the grey cap off??
This means I can't actually use this method to measure my dynamic pressure!
I turned the stopcock off but everytime I tried to take the grey cap off the prv water kept spurting out. I never took the cap off completely as each time I loosened it water was coming out under pressure.
The mains pipe comes up through the floor and then goes all the way up to the thermal store in the loft. So I presume this volume of water sitting in the pipe work above the prv will pour out if I take the grey cap off??
This means I can't actually use this method to measure my dynamic pressure!