No hot water at the breakroom sink (point-of-use heaters)

What this error means

That under-sink mini water heater has a documented check order: power first (many are plug-in — test the outlet with a lamp; others have a breaker), then the high-limit reset — on standard electric units a red button behind the access panel, and on mini-tanks like the Bosch a small recessed button in the middle of the thermostat, pressed with a pen. A tripped high-limit restores hot water instantly and 'solves a surprising percentage of no-hot-water service calls.' The rule that matters: if it trips again, stop resetting — a repeat trip means a failing thermostat or element.

Symptoms

• Cold water only at one sink
• Everything else electrical works
• Unit silent (no heating hum ever)

Try this first (safe DIY steps)

1. Test the outlet (lamp test) or check the breaker
2. Power OFF; remove the access panel; find the reset — red button on standard units, recessed pen-press on mini-tanks
3. Press firmly (a click = it was tripped), panel back on, power on, allow ~20–30 min to heat
4. Check the thermostat isn't dialed to minimum while you're in there
5. Trips again = replace, don't keep resetting

Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.

When to call a technician

Repeat trips mean element/thermostat failure — on $150–300 point-of-use units, replacement usually beats repair; installed swap runs ~$300–700.