As of late a lot of manufacturers will list these contacts on their web sites under support or agencies. Also check the appliance itself for tags or labels that will direct you. Recovery is a term used to quantify the performance of an appliance. It is usually applied to fryers. It is determined simply by measuring the time it takes for a fryer to raise the temperature from 275 degrees to 325 degrees.
Most manufacturers publish standard recovery rates for their fryers.
Some fryers equipped with modern electronics will automatically check this for you every time you start up. This can vary from oven to oven. Ovens equipped with electronic controls can run very accurately for a long time, whereas some mechanical controls can vary quite widely over a short period of time. The best rule of thumb to use is to check ovens equipped with electronic controls at least every 6 months and ovens equipped with mechanical controls every 1 to 2 months. Sometimes you may notice a change in performance e.g. product too light or too dark.