Follow the symptom from thermostat to equipment
For Rosemont service, note whether the thermostat display is active, whether the fan runs and whether heating and cooling behave differently. This gives a clear starting point without requiring a homeowner to test live electrical components.
If the system works intermittently, record when it stops and whether the thermostat still calls. A repeatable description is more useful than replacing a thermostat solely because the room feels uncomfortable.
For gas & propane wall furnace repair, bring intermittent operation and controls into the scope discussion. Identify the brand, model and fuel before discussing repair or replacement. Williams and other wall-heater product families have different designs and part requirements. Any fuel conversion must use approved equipment-specific methods and qualified installation.