ACR X CLB THROUGH OCCUPIED ALT HAD LTSS FROM CPR Y. SYS ERROR.

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ACR X CALLED ON CLBING TO 10000 FT. I TURNED ACR X TO A 270 DEG HDG (A 30 DEG R TURN) AND CLBED THE ACFT TO FL230. THIS WAS DONE TO AVOID CPR Y NE OF FORT WAYNE AT 15000 FT. WHEN I REALIZED THAT THE HDG MIGHT NOT BE ENOUGH; I DECIDED TO TURN ACR X ON COURSE (DIRECT FORT WAYNE) AND STOP ACR X AT 14000 FT. I THOUGHT ACR X READ BACK 14000 FT AND FORT WAYNE; BUT IN ACTUALITY; HE READ BACK 'DIRECT FORT WAYNE.' WHEN ACR X WAS APPROX OUT OF 12000 FT; I ISSUED TFC AT HIS 12 O'CLOCK AND 10 MI; NEBOUND LEVEL AT 15000 FT. ACR X STATED HE HAD THE TFC IN SIGHT; WHICH IN MY MIND; FURTHER ENFORCED THE IDEA OF HIM STOPPING AT 14000 FT. I WENT ON TO HANDLE A FEW MORE CTL ACTIONS IN MY SECTOR. I SCANNED BACK TO ACR X AND NOTICED AT THAT TIME THE MODE C INDICATED 14100 FT. THAT STILL IS WITHIN TOLERANCES. I ASKED THE ACFT; 'VERIFY YOU'RE LEVEL AT 14000 FT.' HIS RESPONSE WAS; 'NEGATIVE; WE'RE CLBING TO FL230.' SEPARATION WAS ALREADY LOST; SO I TURNED THE CLBING ACFT 60 DEGS R AND TURNED CPR Y TO A 090 DEG HDG. I THEN ADVISED ACR X THAT 'I HAD STOPPED HIS CLB AT 14000 FT AND READ HIM HIS TFC.' HE STATED; 'I HAD THE TFC BUT DID NOT GET THE NEW ALT OF 14000 FT.' BY NOW; STANDARD SEPARATION EXISTED; SO I CLRED BOTH ACFT ON COURSE.