The boiler for my apartment building is located in the laundry room, and occasionally a tenant will try to raise the high temperature limit. Normally the temp. fluctuates from between 140-160, but the last time I glanced at it, it was 190. The pressure is still at 20 psi.

I hate to notify the manager, since this is the first time I've had real heat in my apartment, but I don't want the thing to explode while someone's doing their laundry. Is 190 a safe operating temperature?