A Captain reports a continuing abnormal temperature indication of the # 2 engine pneumatic bleed reading higher than the # 1 engine; and the lack of adequate trouble shooting by their Maintenance Department to correct the condition on an EMB-145.

Narrative

Took aircraft in ZZZ after 2 hour scheduled sit and reviewed aircraft history during my preflight. An abnormal Bleed indication had been written up Two times in the last two days; one time being earlier that day. The condition that had been written up was a Bleed-2 Temperature indication that was 'not' normal. Instead of the Bleed temperature arrow being green and at the bottom of the white scale with the Anti-Ice system 'off'; it was constantly in the green arc during cruise flight with the Engine Bleed selected; and 'not' in icing conditions; or with the system Manually selected 'on'. The first time this was written up; Maintenance removed and replaced the Engine Anti-Ice valve on System-2 and Operational (Ops) checked it 'OK'. This did not resolve this discrepancy; however; because on the following day the same discrepancy was recorded by a different Crew. Maintenance had OPS checked the system 'OK'. We departed ZZZ for ZZZ1 and through 10;000 (feet); selected the Engine Bleeds and almost instantly the Bleed Temperature rose on the # 2 side and stayed normal on the # 1 side. The temperature would modulate with a change in thrust lever position; so that it would be at its highest in the green arc at a normal cruise power setting; then as you would reduce power to descend; the temperature would reduce; but still never indicate a normal value like the #1 side. When we arrived in ZZZ1; the discrepancy was recorded on Log Page as item 1: 'With Engine Bleeds selected and cruise power settings above 60% N1; Bleed-2 Temperature indication is abnormal. Temp is in the green band like Icing system is activated; when not in icing conditions.' We were given an XXX code by Maintenance Control and we left the aircraft for the next Crew that would be departing in 2 hours; as this had been the final leg of our trip. Noted on the MFD EICAS page.I am unaware of how Maintenance resolved this discrepancy the 3rd time; but their actions were insufficient to clear the discrepancy the first two times that it was written up. Maintenance seemed to think that this indication was 'OK 'because it was in the green range; but did not seem to understand that this was not a normal indication; possibly showing that something in the system was not working correctly. This could very well be a warning sign that something else is going to fail in the near future; or had already failed; and could very easily lead to an unsafe condition and reduced aircraft reliability. I felt that by reporting this information to Maintenance that it gave them an additional opportunity to diagnose the problem before the condition worsened. Maintenance should be required to use and have in front of them the Maintenance Procedures prescribed in the EMB Maintenance Manual. I find it hard to believe that Maintenance checked to see if the replacement of the valve after the discrepancy was first reported; actually resolved the issue that was reported. I believe that if they had run the aircraft up after replacing the valve they would have discovered that the condition still existed and continued to troubleshoot. Instead; they replaced the valve and returned the aircraft to service. The 2nd time it was just 'Ops checked OK.' I don't know if they did anything the third time; when I reported the same condition; but the point is that it should not have gotten that far. How many times does the same discrepancy have to be reported before the issue is actually resolved? What is an acceptable number; especially with an abnormal Bleed issue? In this situation; I felt like the Crews before me had noticed an abnormal indication that could be very easy to miss and had no associated EICAS message to further alert the crew to an abnormality. Better Maintenance Practices could be used to diagnose and actually fix the problem the first time; instead of returning the aircraft to service multiple times with the same issue.