Overview

The objective of this project is to control the Jandy pool heater. We can either control the heater using it's REMOTE relays or interface with it's RS485 interface.

The equipment we will to interfacing with is the Jandy JXi Gas-Fired Pool and Spa Heater 260N.

Pool/Off/Spa Solutions

Micro Controller

For this solution, we are using a Sonoff SV controller. This is a nice controller since it has everything we need to control the heater's remote relays. Additionally, we can power it from the heater itself since it accepts 5-24 volts input and the heater will supply us with 10v. We are going to use the Sonoff SV in isolation mode by removing the two resisters that would normally supply the power to the controller using the input voltage.

Wiring Diagram

Pictures

Adding a Temperature Sensor

We are going to add a temperature sensor to the heater so that we can turn the heater on or off based on temperature.

We are going to use

• Waterproof Digital Temperature Temp Sensor Probe DS18b20
• a 1/2″ male NPT x 1/4″ compression fitting
• 2 1/4" o-rings

• 3/4" male NTP to 1/2" female NTP adaptor

• teflon tape

We can add one to the outlet (see f in diagram below). You may have a different setup, check your owner's manual for details.

Since the header Type 'B' has a 3/4", we will need a 3/4" male NTP to 1/2" female NTP adaptor.

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References