I have loded my fridge with 406a

Why did you do that? It's a very inefficient gas and very inferior to R-12, as all the new gases are 50% less efficient than the old ones. The pressures depend on temperature, and load determines temperature. A refrigerator using R-406A will run a 9 inch vacuum when the evaporator is at the right temperature. It MUST be charged as a liquid, not a gas because you will get more of one gas than another. Charge an ounce at the time and when at around -9 on gauge make sure to stop and wait. It will be a little high until it gets down to the right temperature in evaporator which is -30° F on inside of evaporator. This equals about -20 on outside of evaporator. You charge and wait because you only use about 6 ounces or so in many refrigerators. You open valve on tank turned upside down and loosen center hose until liquid comes out. You then CLOSE valve on tank and open valve to suction line. This should be about 3 ounces on a six foot hose. Repeat once. Then wait for about an hour and read the gauge. It may be high and then drop to -9. Check the nameplate to see how many ounces you need before charging and put about one ounce less liquid gas in. When charging this way always close the tank valve prior to opening valve to suction line to control amount of gas you charge. When you wait you are looking for a frost line. It should come to an inch or so on line coming out to compressor. If the frost line reaches compressor you put in too much and you may have to vacuum down and start over until you get it right. The frost line is more important than the pressures you get.