Mitsubishi Electric heating and cooling equipment carry the build date inside the serial number. We know 2 serial formats for this brand; the decoder tries each one and shows every reading that fits.
Newer plates print YEAR OF MANUFACTURE or carry a QR code. Use that if present.
The first character is the last digit of the production year and the second is the month (1 to 9, then X for October, Y November, Z December). The decade is not encoded. Mitsubishi uses an April-to-March fiscal year, so a unit built in January to March carries the previous year's digit.
89D00488D reads as September 2018 or September 2008.
Two sources agree Building Intelligence Center, Inspector's Journal decoder
The first digit is the last digit of the year. No month is encoded. T means made in Thailand.
8001637T reads as 2018 (month not encoded) or 2008 (month not encoded).
Two sources agree Building Intelligence Center, Inspector's Journal decoder
A ductless mini-split is a heat pump, so plan on 10 to 15 years, with 20 possible for a lightly used unit that is cleaned regularly.
How long does a ductless mini-split last? · Should I replace my air conditioner? · same range as air-source heat pumps
LG · Fujitsu · Gree · Bosch (heat pumps and geothermal) · ClimateMaster · WaterFurnace
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The age you just looked up is the kind of fact that gets lost. A written record of serial numbers, install dates, repairs and who did the work saves the next owner, inspector or insurer from guessing.
A lifetime logbook for the house, organized by system, with room for serial numbers, install dates, repairs and contractors. It stays with the house for the next owner.
Galvanized, polybutylene, cast iron and the sewer line: what fails, what it costs, what insurance won't cover and how to decide.
A buyer's guide to older homes: wiring, pipes, lead, asbestos, insurance refusals and what the repairs actually cost.
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