Thermoking KD2 SR Defrosting

[Jaymo]

Hi, I have a KD2 SR which seems to initiate defrost once the temperature hits 25deg celcius.
What could the issue be on this one?

[seanf]

https://www.ctrserv.com:8443/phprunner/phprunner10.1/manuals/output/Parts%20&%20Service%20Manuals/thermo%20king/kdIIsr.pdf Page 63 of the PDF / page 49 of the doc.

Maybe the defrost air switch needs calibration?

Maybe the coil has iced up?