I now understand what your goal was, and it has nothing to do with the boiler temp. Two issues are the only place to look, and as Rob and others said, the domestic coil might be clogged, and/or the mixing valve is compromised. If the mixing valve can be taken apart, you may be able to clean it out and free up its operation. I have not been that lucky in most cases, so I'd plan on a replacement. The coil in the AA can be flushed in place, however if you are feeling like you want to remove it, understand that those bolts are NOT going to come willingly. Start soaking them today and for a few days, A torch is the only safe method to get them off in the event you do need to remove them. You should be able to have any temp you desire at the sinks, remembering that 130 is on the high side, and 140+ is dangerous. Know where the shutoffs are before you start is a good idea. Most homes don't have enough or they may be 'leakers' also. Good luck!