Hi - can someone tell me please where to find the water pressure gauge on my IDEAL LOGIC 18 boiler. I had it installed 3 years ago and its been fine. I have just turned my heating on ready for the autumn and notice that the downstairs radiators aren't getting hot, so I though that the first thing I would do is bleed the radiators (no air inside, cold water came out). No air in upstairs either (very hot water came out). So I went to check the pressure gauge, but I just cant find it ? photos attached. I looked underneath, on top, inside...but no gauge. Many thanks