Navien NPE-180A Service Manual

Also see for NPE-180A: Installation manual Installation & operation manual Specification sheet Installation manual Operation manual

Contents

Navien NPE-180A Service Manual Manual pdf 108 page image

Troubleshooting 1075.1.16 439ErrorError occurrence conditions and check itemsError DescriptionE439Flow sensor errorAs one or more units are operating in the cascade system, if no flow is detected while the system opens thewater adjustment valve, the system considers it as a defective flow sensor. The system displays 439E (clearedmanually) on the front panel and switches the unit operation into the Lock-Out mode (gas valve and ignitiontransformer locked).Check items1. Check the supply of cold water while the cascade system is disabled. (frozen/locked valve).2. Defective flow sensor.3. Defective PCB.Check flow sensor connector (CON6)Clean water flow sensorDisable cascade operation andopen faucetCheck cold water supplyNOIs there water flow?Yes