Pressure Gauge Faulty Reading ?

[watford 99]

I finally got around to draining and refilling my 20 evacuated tube solar H.W system this weekend. I did not find the task particularly straight forward but I guess I was on a steep learning curve. However, one thing I did notice, which disturbs me, was that the pressure gauge on the pump station did not zero when the system was empty and the drain/ fill valves were open.  It did not drop below 0.8 bar. When I refilled and pressurised the system the reading rose to 2.6.bar.

I assume the gauge is, in a word, knackered but as it is probably only 6 years old I am surprised and disappointed. I do not know if replacement would be straightforward. Probably not now the system is refilled. Would anybody know how accurate the  2.6 bar reading might be or should I deduct 0.8 and assume 1.6 bar is probably nearer the correct pressure ? One other query, this time regarding the 6 bar prv. With the system pressure well below 6 bar should I definitely get solar fluid to discharge when I rotate the cap ? As you can see, I am still on the learning curve.

[baker]

Hi
some older type gauges you can turn the complete casing  to calibrate the gauge reading in side to  0
also maybe you can fit a second gauge to the filling point and open the the valve to calibrate the
existing pressure gauge  and no need to drain down
 

[watford 99]

Baker

Thanks for the suggestions regarding my pressure gauge. On re-reading my query I see that I deducted 0.8 from 2.6 and made the answer to be 1.6. Perhaps I should have added 'approximately'. The dial of the gauge can't be rotated. I may follow up your idea and buy a gauge to connect to the drain or refill valve. I see one advertised for about £11 but it has a scale of 0 - 11 bar and I wonder about its accuracy for pressures around 1-2 bar. The faulty gauge carries the name 'Paw'.

[baker]

Hi
any plumbing shop should have a gauge
or get one off a old boiler
baker