Wyze thermostat 2 stage radiant heater

Hello,

I installed a Wyze thermometer on a 2 stage SRP 80,000btu natural gas heater in my garage. Thermostat fires the heater and appears to work, but when the thermostat goes through the test, stage 2 does not fire.

There is an R wire, C wire and W1 and W2 only, no cooling.

Any ideas on this ? Or is the test just not triggering stage 2 properly?

Thanks

Andy