Most State problems map to recognizable symptom patterns. Gas units have an LED flash code on the gas valve — see error codes hub. Electric units don't have a code system; diagnosis is by thermostat and element testing.
No hot water — gas units
Check the LED flash code on the gas valve first:
- 1 flash steady = normal operation but burner not firing; check thermostat setting
- 2 flashes = thermopile voltage low (pilot won\'t stay lit); replace thermocouple
- 4 flashes = high-temp lockout; check water flow and ECO reset
- 5 flashes = vacuum / draft (atmospheric); check chimney
- 7 flashes = gas valve fault; replace gas control
- 8 flashes = combustion air switch / intake blocked; clean intake
No hot water — electric units
(1) Check breaker (most common cause); (2) press ECO reset (red button) behind upper access panel; (3) test upper element and thermostat; (4) check for tripped ECO with continuity test.
Lukewarm water — electric
Lower element or lower thermostat failed. Upper section heats; lower stays cold.
Hot water runs out fast
Most common cause: broken dip tube mixing cold water into hot at the top of the tank. Replace the dip tube — $5-15 part, 30 min DIY. Less common: heavy sediment reducing effective capacity (flush the tank).
Premier Hybrid heat pump issues
- Mode setting: if accidentally on "Heat Pump Only" in cold ambient, output may be inadequate. Switch to Hybrid mode
- Breaker: 30A double-pole. Trips repeatedly indicate compressor or wiring issue
- Air filter: clogged filter shuts down heat pump mode. Vacuum monthly
- Condensate drain: full pan triggers safety shutoff. Verify drain is clear
- Resistance backup element: if heat pump compressor fails, unit defaults to resistance mode (slow recovery, high energy use). Test backup element with multimeter
Water heater leaking
Top of tank fittings: tighten or replace washers. T&P valve: thermal expansion (install expansion tank) or failed valve. Bottom of tank: tank shell failure — replace the unit. See water heater leaking for full diagnosis.
Popping or rumbling noise
Sediment buildup at tank bottom. Flush the tank.
Rotten egg smell
Sulfate bacteria reacting with magnesium anode rod. Switch to aluminum-zinc anode rod and shock-chlorinate. See sulfur smell.
Power Vent specific issues
- Won't fire — 5 flashes: draft / vacuum switch. Check vent for obstruction or condensate buildup
- Fan noisy: bearings approaching end of life; fan motor replacement
- Fan won't start: 120V outlet, capacitor, motor — diagnose in that order
Bottom line
For gas units, the LED flash code on the gas valve identifies most failures. For electric units, breaker → ECO reset → upper element → upper thermostat sequence. For Premier Hybrid, check mode setting and air filter before suspecting compressor.