Rick Hughes was thinking very hard :
I have a Clarke Warrior 60 electric air compressor.

I went to use it and found that while it compresses air fine .. it is not
cutting out when it reaches set pressure .... it just continues 'pumping
until the safety over-pressure valve 'blows'

This is not related to outlet pressure (regulators are fine) but the pressure
that the main cylinder pressure switch operates (or in this case doesn't)

It has one of the integrated units ...
http://www.machinemart.co.uk/shop/pr...20-amp-1-phase


Anybody know if they are serviceable?

They are adjustable if you take the top cover off - maybe the
adjustment has drifted. Secondly the over pressure valve might be set a
bit low and tripping before it should - is there a pressure gauge
fitted?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk