I am not sure whether it's a heating unit issue or the piping/plumbing issue. I have already called maintenance twice for not getting hot water. When they show up, hot water comes back for several days, then disappears. I already bought another unit, but I still have doubts that it is a pipe layout issue. Looking for a hero that can help.

Hi arbawi and welcome, you've come to the right place, the plumbing "hero's" here work wonders with the right information. Post what kind of system is giving you trouble, pictures help.