I live in an apartment that was recently gut renovated and I have a new hot water heater as well.

The issue is that I have to turn on the heat in order to get hot water in the shower, kitchen and bathroom sinks, otherwise the water is cold.

When the heat is on, the water is very hot, but otherwise just cold.

What is the deal here? Could it be an issue with water lines being crossed when the new pipes were installed?

Thanks.

Does you apartment have an actual, separate water heater or is this a combi boiler? Is there a superintentedent in the building or do they have a maintenance person? Tenants should not attempt repairs, your are liabile for any damages. Is this your situation?

Thanks for the response and your concern. I'm actually friends with the owner of the building so I'm trying to help with the repair (I'm doing the research) but I'm not very familiar with the "ins and outs" if you will. I'm definitely not going to attempt to fix this on my own, I know my limitations.

The reason for the question is that I haven't been able to find an answer online and it is a strange issue in my mind.

The owner thinks there is an issue with a mixing valve or one of the hot / cold water lines was crossed during the renovation.

This is a combo boiler... any ideas?

Thanks in advance.

What do you mean turn on the heat? Are you turning on Gas or electric breakers? It may be on the same breaker as the furnace.