Sudden cold showers: what am I missing with my heater?

Yeah, flushing only gets you so far. I had a similar issue last winter - turned out my dip tube was basically disintegrated. Replaced it and suddenly the hot water lasted again. If you’ve got an electric heater, those elements are notorious for dying quietly too. Sometimes it’s just one thing, sometimes it’s a combo. Worth checking both before you start thinking about a new tank...

The heater in the opening post is gas-fired, so an electric tank’s upper/lower element and thermostat checks aren’t the same diagnostic route. It would help to get the exact model and keep any electric-heater examples clearly labeled.

For this gas unit, record when the temperature falls and any status code, then have the burner, controls, venting and water-side components assessed as appropriate. Don’t start adjusting gas controls or opening equipment on the assumption that someone else’s electric-heater fix applies.

The upper-thermostat/lower-element example is specific to an electric storage heater, so it shouldn’t be used to diagnose the gas unit in the opener. On an electric model, a control or connection problem can resemble an element fault, but the tests need the correct wiring information and safe isolation.

A reset button staying in doesn’t rule out a fault. If there are concerns about a breaker, wiring or internal connections, have a qualified person investigate rather than probing around inside the panel.

Getting the model and fuel type straight first would save a lot of guesswork here. Multimeter work can help a qualified technician trace an electrical fault, but a loose-connection story from another heater doesn’t establish what’s wrong with this one. The owner’s useful starting point is the symptom pattern and any accessible status indication, without opening covers or disturbing wiring.

I hear you on the multimeter magic, but honestly, sometimes I think those things are just a decoy for my real problem - my own forgetfulness. Last winter, I spent half a day blaming the wiring, only to realize I’d flipped the breaker off while vacuuming and never turned it back on. Before I go full Sherlock with tools, I check the obvious stuff now... saves me some sanity (and a few bucks). Sometimes it’s not the heater, it’s just me being scatterbrained.