Heater Control

I have a Hayward Series H200 heater for my spa, it is relatively new.

The following should work for any recent Hayward heater though. It would be best to check the installation manual for the heater, a lot of the following is based on what I learned from the Hayward installation manual.

There are two options for controlling this heater, Hayward calls the two options three wire or two wire mode.

With three wire mode, you use three wires to put it into either pool or spa mode, and the heater's internal thermostat is used.

With two wire mode, you use two wires. If you short the wires, heater is turned on. You need an external thermostat to decide when to turn the heater on or off. You also need to put the heater in Bypass Operation, which is explained below.

So I decided to use three wire mode. This way, heater can be somewhat remotely controlled with my ESP, or it can still in controlled manually at the heater control panel. The drawback here is that you can't set the temperature with the ESP, but life is full of compromises lol.

Three Wire Operation

For three wire mode, heater should be on, and in standby.

But make sure everything, especially the heater is off before doing the wiring.

Three wires are connected through the heater's side panel. Heater is supposed to have the same wiring blocks on either side, but one side of my heater is against a wall, so I can only get to one side. See where the power wires enter the heater, this is the side panel you need to remove. (unless you can get to either side, then you have your choice).

Take out a couple screws, and remove the side panel. Because of how my heater was installed, I had to disconnect the power wires at the other side (timer box) to have enough slack to get the side panel away from the heater. Once the side panel is away enough, you can unscrew the terminal screws that connect the power wires and disconnect the power wires. Then you should be able to remove the side panel complete. Just note where how the power wires were connected, so you can reconnect after. I ended up rewiring the power wires, and I made them longer so I could remove the side panel more easily.

I removed a cap on the side panel (you can see it by looking closely), and installed a 1/2 watertite conduit between the side panel and my ESP box. I ran three wires from the ESP box through the conduit. I used 20 gauge, Hayward recommends to use 20 AWG for runs over 30 feet, and 22 AWG for runs less then 20 feet. Runs should not exceed 200 feet. My run is short, but used 20 AWG anyway.

DO NOT RUN these wires in the power conduit, has to be kept separate.

On the remote control wiring terminal block, connect the appropriate wires from your remote control to these terminals:

Pool mode - orange

Common 24V - white

Spa mode - red

If common wire is shorted to pool mode orange wire, then heat turns on, and goes to pool mode.

If common wire is shorted to spa mode red wire, then heat turns on, and goes to spa mode.

I use two relays to select either pool mode, or spa mode.

On the heater, I went to pool mode, and set it manually to a relatively warm temperature on the front panel.

Then I went to spa mode, and set it to a relatively hot temperature.

So you can now select pool mode for warm, and spa mode for hot.

If you turn off pool/spa mode (open relay), then heater will go back into standby. In standby, you can use the front panel like normal, to turn on the heater in either mode, and set temperature.

The only difference I can see between pool and spa mode is they allow you to set different temperatures. Heater seems to act the same in either mode.

Two wire operation

For two wire operation, you need an external thermostat.

You put the heater in "bypass operation", and use the external thermostat to control heater.

To configure the heater for 2- wire remote thermostat control, use the “MODE” key on the heater keypad

to put the control into “STANDBY” mode. Then press and hold both the “DOWN” and “MODE” keys for 3

seconds until the display shows the code “bo”, for "bypass operation".

Now make sure everything, especially the heater is OFF before doing the wiring.

Two wires are connected through the heater's side panel. Heater is supposed to have the same wiring blocks on either side, but one side of my heater is against a wall, so I can only get to one side. See where the power wires enter the heater, this is the side panel you need to remove. (unless you can get to either side, then you have your choice).

Take out a couple screws, and remove the side panel. Because of how my heater was installed, I had to disconnect the power wires at the other side (timer box) to have enough slack to get the side panel away from the heater. Once the side panel is away enough, you can unscrew the terminal screws that connect the power wires and disconnect the power wires. Then you should be able to remove the side panel complete. Just note where how the power wires were connected, so you can reconnect after. I ended up rewiring the power wires, and I made them longer so I could remove the side panel more easily.

On the remote control wiring terminal block, connect the appropriate wires from your remote control to these terminals:

Pool mode - orange

Common 24V - white

If common wire is shorted to pool mode wire, then heat turns on. It will stay on until it hits the max of 104 if you don't turn it off.

To operate the heater by remote thermostat, the heater’s control must be in either “POOL” or “SPA”

mode. The display will show “bo”. The “POOL” or “SPA” LED will be illuminated. The remote thermostat

will operate the heater. The heater’s thermostat will function to limit the water temperature to a maximum of

104°F.

I have seen instructions that say you need to remove a jumper for bypass remote operation, but this must be for older heaters where you cannot set it up using the front panel as described above.

However, now you have to implement a thermostat type function in a script, which is easy enough and I may do it. Need to be able to enter a temperature, and just turn off heater when it is a little hotter (0.5 degrees) then target temp, and turn on when its more the 0.5 degrees colder.

- platform: mqtt

name: "Spa Heater Spa"

command_topic: "esp04Spa/cmd"

state_topic: "esp04Spa/SpaHeaterSpa1"

payload_on: "gpio,13,0"

payload_off: "gpio,13,1"

optimistic: false

qos: 0

retain: true

- platform: mqtt

name: "Spa Heater Pool"

command_topic: "esp04Spa/cmd"

state_topic: "esp04Spa/SpaHeaterPool1"

payload_on: "gpio,12,0"

payload_off: "gpio,12,1"

optimistic: false

qos: 0

retain: true