Let me know if you think this plan will work:
Background: I recently built a wooden hot tub. Its heated using a navien tankless combi-boiler through a heat exchanger to the tub jet plumbing. I need to control the system so that the heater and pool pump turn on when tub temp drops below X and off above x. A simple thermostat should do this no problem, but I have struggled to find 24v wireless ones with set temps on the 100-105 F range. I have an Apollo one that looked promising but its a headache and now I can't find the c4 driver for it that they said they had.
New Plan: Z2IO with external temp probe in the tub the 2 CC switches to the pump relay and heater control board. Program variable with custom button to choose set temp from list of four temp options (50, 80, 95, and 103 degrees).
Programing: 1. When temp is 3 deg less than var turn on pump and heater. 2. when temp is 1 deg greater than var shut off pump and heater.
The 4 degree buffer should help prevent short cycling on the pumps.
Anything I am missing or suggestions for better options?
tia
dave