Where do I wire a relay for my Hayward HM400?

[episking]

I'm trying to install a relay to control the heater for my Hayward HM400ED2, and I'm having trouble determining where I should run the NO and COM wires from the relay to the heater... This particular heater has a control for Spa and Pool, so my understanding is that once I've got it wired up, I'll want to set it to SPA, and set the temp control (manual dial) to as hot as it will go. Here are some photos:

 

[JamesW]

It looks like the location is specified?

 

[episking]

So the normally open wire goes there and COM(mon) goes to 24VAC somewhere? That's the part I'm slightly confused on... Where the common goes.

 

[JamesW]

Can you show the switch?

The switch should just be open and closed for on/off.

The remote switch just breaks the line.

 

[episking]

This is the heater's "switch"



And the control board I'm connecting to is a Sequent Microsystems 8 Relay HAT for Raspberry Pi:
Eight Relays 4A/120V 8-Layer Stackable HAT for Raspberry Pi


Thanks for the quick replies!!

 

[JamesW]

It looks like the remote goes in series with the pressure switch.

 

[episking]

Got it, so I think I just need to wire the NO and COM wires to one of each side of the break in the RED wire (where the wiring diagram reads "Connection for field installed control switch")? Am I understanding that right?

 

[episking]

Wired it up as stated before and it's working like a champ!

Thanks for the help!