How it works
How the equipment works, as the manufacturers' own documents describe it, and where brands differ. Every point links to the page it comes from.
How House Works EditorialChecked against sources,
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- How House Works Editorial
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- HHW · HOW-IT-WORKS
- Based on
- Manufacturers' manuals and technical bulletins
- Gas water heater pilot won't stay lit: thermocouple, thermopile and the status light
What Rheem, A. O. Smith, State and Bradford White manuals print about the pilot and the gas valve, relighting, status light blinks and the thermal switch.
- Why a mini-split stops heating for a few minutes in winter: defrost and hot start
Mitsubishi, Daikin, Fujitsu and MRCOOL manuals on defrost and hot start: how long heat stops, what the lamp or display shows, and what they treat as a fault.
- What a standby generator does when the power goes out: transfer, retransfer and the weekly exercise
How Generac, Kohler, Briggs & Stratton and Champion standby generators start, transfer, return to utility and exercise, with each manual's delays and times.
- How a gas furnace lights, and how the control board blinks a failure code
The heating cycle in Carrier, Goodman, Lennox, Rheem, Trane and York furnace manuals, step by step, and why 3 flashes means different faults on different boards.
- How a tankless water heater lights: ignition codes by brand
What Navien, Rinnai, Rheem and Noritz manuals say happens when you open a hot tap, the ignition attempts they print before the code, and the reset.