Can Mysa Smart Thermostat delay second-stage heat for hydronic systems?

Last updated: June 29, 2026

Overview

Mysa Smart Thermostat can support a delay from Stage 1 heat to Stage 2 heat when the HVAC system is wired and configured as a compatible multi-stage system.

The stage delay can be set from 10 minutes to 120 minutes, in 10-minute increments.

Using Mysa with hydronic or radiant heat plus another heat source

Some customers want Stage 1 to run a hydronic or radiant system first, then bring on another heat source, such as forced-air heat, after a delay. This may be possible from a wiring perspective, but it is not a simple drop-in setup.

If the two heat sources use separate 24V transformer sources, the system needs additional wiring and isolation relays so those power sources stay separate. For example, Stage 1 might control a boiler or radiant system on W1, while Stage 2 controls forced-air heat on W2.

Because this setup involves multiple equipment controls, Mysa recommends working with a qualified HVAC professional before wiring or changing the system configuration.

Important configuration limits

  • Mysa Smart Thermostat uses one HVAC configuration code at a time.

  • Choose a configuration code that matches the wiring and includes fan operation if the system requires fan control.

  • Mysa cannot treat two separate heating systems as two fully independent thermostats with separate schedules or separate operating profiles.

  • Early-On or adaptive recovery may not work as expected when Stage 1 and Stage 2 heat sources recover at very different speeds, such as radiant heat compared with forced-air heat.

What to check before proceeding

  1. Confirm the exact heating equipment connected to Stage 1 and Stage 2.

  2. Confirm whether each system uses the same 24V source or separate transformers.

  3. Confirm whether fan control is required.

  4. Have an HVAC professional verify whether relays or other isolation components are needed.

  5. Contact Mysa Support with photos of the thermostat wiring and control board if you need help identifying the correct configuration code.