I live in a building ( papartments made into condos and we share heat and hot water ). I have noticed that sometimes the water in my kitchen sink gets extremely hot and I am thinking this happens when the unit above me is running their dishwasher ( we are not supposed to have dishwashers ) I would think that I would have the opposite problem - not enough hot water. Is this possible ?

A great deal depends on how these units were plumbed when they were built. How many units and do you all share one boiler and one water heater?

I think they were built in the 70's as apartments and then made into garden style condos. We share the boiler/heater and water is pretty much all connected. There are 19 units. Some of us have had water shut-offs installed in our units but often if someone is having work done they need to shut off the main water. I have asked the building manager about the extremely hot water at times and was told no one else has complained.

Chances are your hot water travels so far from the heater to your unit that you are getting slightly cooled down water. Whebn someone uses a dishwasher the hot water has traveled down the pipe and now the whole pipe is charged with hot water. It should happen more so when someone takes a bath

Well, here is my theory: Water gets only as hot as the hot water thermostat setting on the hot water heater. I think, what's happening is that when neighbor's dishwasher draws water during its regular cycle, hot water pipe goes through your kitchen sink location, therefore dishwasher helps to deliver hot water to your kitchen sink faster than usual. In other words, it acts like hot water circulating pump.

Milo