Related illustrations

0831

Primary controller

· p. 139

The illustration shows an older oil-furnace primary controller, also called a primary relay or stack relay, mounted on the exhaust vent connector at a chimney. A heat probe extends into the connector, and an arrow indica

1586

Primary controller

· p. 277

The illustration shows an older oil-fired water heater vent connector entering a chimney, with a primary controller mounted beside the connector. A heat probe projects into the exhaust path to detect heat as evidence of

0834

Primary controller

· p. 140

The illustration shows an older oil-furnace primary controller mounted on the exhaust vent connector where it enters a chimney. A heat probe projects into the connector to detect heat from furnace exhaust, and the contro

0867

Aquastat - primary control

· p. 147

The illustration shows a hot-water heating boiler with a burner, exhaust flue, circulating pump, cool-water return piping, and hot-water supply piping. An aquastat is strapped to the hot-water pipe above the boiler. An e