A Line Mechanic reports he was notified he had replaced the #2 engine Fuel Diverter Valve with a Valve not effective for an A320-200; resulting in the aircraft returning to the gate at a downline station for a Fuel Heat Return Valve fault.

Narrative

July 2009; I received first aircraft; then around XA30pm was given a swapped out A320-200 return to gate aircraft for 'Fuel Return Valve stays open'. So I and Mechanic 'X;' got with swing shift who told us what they had done; like verified that was the problem. Lead Mechanic ordered part for aircraft. I pulled up the Aircraft Maintenance Manual (AMM); and started to remove the Fuel Divert Valve. Mechanic 'X' worked an overnight then assisted later. Once (part) off; we saw that the last digit on Part Number (P/N) was different so I went in and checked effectivity; I thought that what I saw was the right part. so I installed P/N XXXX-75; and removed XXXX-76. Did a FADEC BITE TEST OPS NORMAL. Ran engine for leaks and faults; all checked normal. Did not find out about this problem until I got to work the next evening. I could not believe it.From what I was told; when (aircraft) was pushed back in ZZZ; Pilot got a FUEL HEAT RETURN VALVE FAULT. Mechanic found it faulting #2 engine. Maintenance Control checked P/N; found not to be effective for a V2500-A5 engine. This is all I know. So in ZZZ; Mechanic installed a new Diverter Valve. Mechanic in ZZZ changed out part; took a delay. Maintenance Control found part to be wrong P/N. Whoever orders part for any aircraft; make sure its the right effectivity. The Illustrated Parts Catalog (IPC) can be trying at times.