A B737-700 WAS DISPATCHED IN NON COMPLIANCE WITH THE #2 ENG PRESSURE REGULATOR AND SHUTOFF VALVE RENDERED INOP IN CONFLICT WITH THE MEL.

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ACR X'S ACFT FLEET X; ARRIVED ZZZ APPROX XA10 LCL; WITH #2 ENG ANTI-ICE 'LIGHT' WRITTEN UP AS 'ILLUMINATED ON DEP; BUT EXTINGUISHED JUST PRIOR TO LEVEL OUT.' AFTER CONSULTING WITH ACR X MAINT CTL IN ZZZ1; DECISION WAS MADE TO DEFER PER ACR X MEL 30-3F. THIS ENTAILED OPENING #2 ENG FAN COWLS AND #2 ENG (R HAND) THRUST REVERSER 'C' DUCT. DRAWING PROVIDED IN MEL FOR COWL TAI VALVE; AND HIGH STAGE (9TH) BLEED VALVE; WERE VAGUE AND DID NOT MATCH CONFIGN OF ACFT. MAINT CTLR WAS UNABLE TO FAX US CORRECT MAINT MANUAL. INSTEAD RECEIVED UNRELATED TECHNICAL MATERIAL. WAS ABLE TO SUCCESSFULLY DEACTIVATE AND LOCK TAI (THERMAL ANTI-ICE) VALVE IN OPEN POS. THEN PROCEEDED; AFTER DISCUSSING WITH MAINT CTL; TO LOCK OUT; IN CLOSED POS; WHAT I BELIEVED TO BE THE 9TH STAGE ENG BLEED VALVE. ACFT LOGBOOK WAS SIGNED OFF AND ACFT RELEASED FOR SVC. APPROX 2 HRS LATER; WHILE REVIEWING ANOTHER AIRLINE'S COMPONENT LOCATOR GUIDE AND MAINT MANUAL; I WAS HORRIFIED TO SEE THAT I HAD NOT LOCKED OUT THE 9TH STAGE BLEED VALVE; BUT THE PRESSURE REGULATOR AND SHUT OFF VALVE; LEAVING THE ENG UNABLE TO PROVIDE PNEUMATIC PRESSURE TO THE ACFT. I IMMEDIATELY NOTIFIED MAINT CTL OF THE ERROR. THE ACFT LANDED SAFELY AT ZZZ1; WHERE MAINT OPENED THE PRSOV; AND LOCKED CLOSED THE 9TH (HIGH) STAGE BLEED VALVE. IN DISCUSSING WITH THE MAINT CTLR ON DUTY; (A DIFFERENT ONE THAN HAD ASSISTED ME WITH THE MEL EARLIER); WE DETERMINED THAT THE ACFT STILL HAD NOSE COWL ANTI-ICE; AS THE TAP OFF FOR NOSE COWL TAI IS UP-STREAM OF THE PRSOV. THE ONLY DIFFICULTY THE CREW EXPERIENCED WAS; WITH THE R AIR CONDITIONING PACK OPERATING; R HAND DUCT PRESSURE DROPPED TO ZERO. (NO AIR FROM #2 ENG.) THE CREW SHUT OFF #2 R AIR CONDITIONING PACK. WHEN THEY DID THIS; THE BLEED AIR ISOLATION VALVE WHICH WAS IN 'AUTO' POS; OPENED PRESSURIZING THE R HAND PNEUMATIC DUCT; AND PROVIDED TAI BLEED AIR FOR WING ANTI-ICE R HAND SIDE. THE L AIR CONDITIONING PACK WAS SUFFICIENT TO MAINTAIN CABIN PRESSURE; BASED ON ACFT ALT AND ROUTING. ACFT PROCEEDED TO INTENDED DEST WITHOUT INCIDENT; AND COMPANY MAINT INSURED PROPER DEACTIVATION OF ANTI-ICE AND PNEUMATIC SYS. POORLY WRITTEN INSTRUCTIONS IN THE MEL. FOR INSTANCE; 9TH STAGE BLEED VALVE; AND HIGH STAGE BLEED VALVE ARE BOTH REFED; BUT NOT TOGETHER TO MAKE IT CLR THEY ARE IN THE SAME VALVE. POOR DRAWINGS IN THE MEL WHICH FAIL TO REFLECT THE CONFIGN OF THE B737-700; AND WHICH FAIL TO PROPERLY LOCATE THE 9TH STAGE BLEED VALVE. NOTE: BOTH 9TH STAGE AND PRSOV VALVES ARE CLOSE TO EACH OTHER; AND LOCK OUT IDENTICALLY. THE MAINT MANUAL PROVIDED BY THE MANUFACTURER IS FAR SUPERIOR TO THE MEL USED IN THIS CASE.