Water pressure sensor wiring after replacing heater header


New member
Aug 19, 2013
Hello everyone! I recently replaced my Hayward h350fdn pool heater header and for the life of me I can't remember how to wire up the sensors. Can someone help? The three I'm having issues with are the temperature limits and pressure switch.


Pool Clown

In The Industry
Sep 5, 2008
Silicon Valley, CA
The temp limits may, or may not be wired in series and are simple switches NC and open when subject to higher temps. The water sensor is a thermistor. The connection to the board for the switches may say hi temp, or limit, HL1 and HL2, hi limit, or may just say 1 and 2. The temp sensor may say sensor or temp and may be a three wire connection.

Sorry, i'm not much help with Hayward heaters.