we currently have a boiler which provides heat and hot water to the house. All of a sudden we're not getting "hot" enough water coming out from the shower or sinks. The temperature on the boiler is registering high. Any thoughts?
1. The circulator pump (is there one?) for the domestic hot water has stopped or failed. Yes, some boilers have the hot water coil (heat exchanger) off to one side and a circulator pump is needed to get the boiler water back and forth.
2. The hot water coil is lined with sediment or calcium deposits or scale.
3. Some foreign object has obstructed the hot water line, the boiler coil is a possible location.
4. Your system has a master antiscald valve or tempering valve and that has failed or gone out of adjustment, letting too much cold water into the hot water trunk line. This is usually visible just outside the furnace and includes a "short circuiting" pipe between the hot water coil inlet and outlet. (Single knob shower faucets sometimes have local tempering valves.)