predetermined range then the control system is adapted to relieve the hydraulic pressure supplied to subsurface safety valve 11 and allow it to close a typical control system of the prior art is enclosed in dashed lines in fig1 the prior art system includes a high pressure hydraulic supply 21 and a low pressure pneumatic instrument supply 23 high pressure hydraulic control supply 21 supplies hydraulic fluid to subsurface safety valve 11 through a relay 25 instrument pressure is supplied to relay 25 by low pressure instrument supply 23 through a high pressure sensor 27 and a low pressure sensor 29 sensors 27 and 29 are connected to receive tubing pressure through a manifold system 31 as long as tubing pressure remains within the predetermined pressure range sensors 27 and 29 remain in the inservice position to supply instrument pressure to relay 25 if however tubing pressure varies outside the predetermined range then sensor 27 or sensor 29 will shift and bleed instrument pressure from relay 25 whereupon relay 25 will shift to bleed hydraulic pressure from subsurface safety valve 11 which will allow subsurface safety valve 11 to close relays of the type of relay 25 normally have a manual override feature which allows subsurface safety valve 11 to be closed manually and a lockout and manual reset feature which prevents relay 25 from automatically returning to the reset position after it has tripped a control system which includes the pressure controller of the present invention is designated generally by the numeral 33 control system 33 includes a high pressure hydraulic control supply 35 which supplies high pressure hydraulic fluid to subsurface safety valve 11 through a pressure.