Best practice for remote controlling electric patio heaters

ESPHome
1

I am planning to remotely control my electric patio heaters, and I am looking for advice on best to control the loads.

Equipment plans:

  • The heaters are 240V 3KW 13.3A.
  • The heater has a 50% or 100% power setting, controlled by connecting L1-A + L1-B + L2 = 100%, L1-A + L2 = 50%, L1-B + L2 = 50%.
  • I am in the US with split-phase service, and I will power from a 2-pole GFCI breaker to get 240V.
  • I will control the loads with ESPHome with 2 low current relays switching 120VAC.
  • I will use a high current DPST relay to control the 240VAC.
  • I will use a high current SPST relay to control the 50% or 100% load setting.
  • I will power the control relays with 120VAC via the ESPHome relays.

Background:

  • I used to have natural gas patio heaters, controlled from a 120VAC outlet, that was controlled from my commercial Vantage home automation system.
  • I added a poly roof over the patio, and removed the gas heaters because they need too much clearance, while electric will work fine.
  • The 120VAC circuit is 14GA, and although I do believe that NEC says that 14GA can power resistive loads with a 20A breaker, and downrating to 16A I could power one heater if I convert the 120VAC outlet to 240VAC.
  • The alternative is to run new conduit and use 10GA wire, that will leave me with headroom, but more work and cost, especially getting the conduit into the panel.

I have a few options to explore:

  • Any downside to control the 240VAC load with a DPST relay near the heaters, i.e. line is always live and can power ESPHome that would be permanently on?
  • I could use “inexpensive” but not UL listed DIN mount power relays, given I will use a GFCI main breaker, does using “inexpensive” parts pose a significant risk?
  • For the ESPHome device I could use something like the SC-EN-I6-RO4 Norvi or BR4A4AL ASTRA both in DIN form factor. (I could also use a Shelly Pro, but I prefer ESPHome)
  • For the enclosure some outdoor weather and UV rated enclosure, with DIN rails, and grommets for power in and out.
  • If I do run new wire, I could use the existing 14GA Vantage outlet for primary remote control, powering the control relays, and use ESPHome for secondary control of 50%/100% only.

Anybody with experience building such a system, or any better ideas, or gotchas, or advice?