{"schemaVersion":1,"slug":"iec-room-thermostat-plan-mark","name":"Room thermostat plan mark","kind":"symbol","abbreviation":"TS","aliases":["wall thermostat","temperature controller plan mark","heating thermostat"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEC"],"summary":"Plan mark for a wall-mounted room thermostat controlling heating or cooling equipment.","description":["A room thermostat is drawn as a small circle or square with a temperature mark, a theta or the letter T, at its wall position. A control link connects it to the heater, valve or air-conditioning unit it controls.","Its position affects comfort: it should not be near heat sources, in direct sunlight or on an external wall. The plan gives the designer a chance to check this, and the mounting height is usually stated in notes.","It does not show whether the thermostat switches mains directly or provides an extra-low-voltage control signal. Wiring type follows the controlled equipment."],"readingNotes":["Check its position relative to heat sources.","Identify what it controls."],"drawingChecklist":["Link to controlled equipment.","State control voltage.","Give mounting height."],"distinction":"A schematic temperature switch shows a contact; the plan mark locates the room control.","facts":[{"label":"Graphic cue","value":"Circle with temperature symbol"},{"label":"Placement check","value":"Away from heat sources"},{"label":"Exact standard graphic","value":"Not reproduced here; confirm the form against IEC 60617 and the project legend"}],"references":[{"sourceId":"iec-diagrams","relevance":"IEC graphical symbol context; independently drawn here."}],"related":["temperature-switch-no","iec-electric-heater-plan-mark"],"artwork":"s28-iec-room-thermostat-plan-mark","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Thermostat","reference":"IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier."},"plainEnglish":{"title":"What does Room thermostat plan mark mean?","introduction":"A room thermostat is drawn as a small circle or square with a temperature mark, a theta or the letter T, at its wall position. A control link connects it to the heater, valve or air-conditioning unit it controls.","example":"Its position affects comfort: it should not be near heat sources, in direct sunlight or on an external wall. The plan gives the designer a chance to check this, and the mounting height is usually stated in notes.","drawings":"It does not show whether the thermostat switches mains directly or provides an extra-low-voltage control signal. Wiring type follows the controlled equipment.","terms":[{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"IEC graphical symbols for diagrams","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/"}],"detail":"Plan mark for a wall-mounted room thermostat controlling heating or cooling equipment. A schematic temperature switch shows a contact; the plan mark locates the room control.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-room-thermostat-plan-mark","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-room-thermostat-plan-mark.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"iec-diagrams","title":"IEC graphical symbols for diagrams","publisher":"IEC","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/","type":"standard","scope":"IEC 60617 and related symbol-design publications. Full database access requires a subscription.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"IEC graphical symbol context; independently drawn here."}]}