Sounds like you have a tempering/mixing valve fitted controlling the maximum temperature to the areas that you are currently getting luke warm water too. Hire the services of a registered Plumber to check it all out for you.
It is also possible you may have a faulty faucet causing the mixing of both hot and cold water as well.
As I said have it checked out to be sure.
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Craftsman Gasfitters, Plumbers, Electrical Service Technicians