New member from Central California


New member
Jul 28, 2020
Central California
I've been a pool owner for about 4 years now and have had no major problems until this weekend. Our JXI 400N heater displayed a fault code "fuselink/field" and now the spa isn't heating. Found this website and have read a bunch of information so thanks for that. Time to troubleshoot this weekend.


Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015

Welcome to TFP!

Check air flow intake to your fan and the exhaust piping. If there is and obstruction it can cause a fire so there's a sensor in the exhaust gas piping that shuts the heater down before a fire happens. The sensor is a single-use so it needs to be replaced after the obstruction is cleared. There are a few other potential causes but usually it's due to an obstruction. Can also be a bad connection at one of the wires to the sensor or a failed sensor but they don't fail too often. Is your heater outdoors or indoors? A photo of your equipment would be very helpful.