Norcold model N3150 not cooling properly

Norcold model N3150 cooling on and off. This is abnormal for a Norcold to cool for 8 hours at proper temperatures, then stop cooling for 8-12 hours. We experienced this as a recurring cycle for about 2 weeks. The frig was under warranty so Norcold was heavily involved in our repair on this frig. We first tested the integrity of the thermistor, which proved to be functioning properly. We then replaced the optical display panel which interprets the readings from the thermistor. The frig still would cool for about 8 hours and then warm up for the rest of the day. We had perfect leveling, no ammonia leaks, good ventilation, and the 12 volt fan was running as intended. This Norcold N-3150 was not cooling properly on propane mode, AC power mode, or DC power mode. Still we verified there was a perfect blue flame under the flue while in propane mode, the heating element alongside the boiler tube was pulling 2.3 amperes while in AC mode, and so the cooling unit’s boiler tube was being supplied with good heat sources. We also unplugged the thermistor and changed the cold setting to max and still got no results. Norcold decided to replace the refrigerator entirely. They sent us a new replacement n3150 which pleased our customer greatly. The frig took a total of about 10 days to reach our business in Gainesville, Fl. We installed that frig the same day and the problem was gone. Therefore, it was not any problem with the RV power sources or leveling. We theorize a possible cause as being an improper ratio of the chemicals inside the cooling unit. Anhydrous ammonia, sodium chromate, water, and hydrogen are sealed inside the cooling unit. If this ratio is not perfected at the factory it can result in poor, intermittent, and no cooling situations. Since this frig was fresh from the factory, only 1 month old and never could keep cool since first turning it on, we believe the issue was an improper refrigerant mixture.