MRFT630 AC but no DC

[Larry]

OK, it's old but the AC side still works fine on my Norcold MRFT630. Using 12v power however is a different story. There's no compressor activity, no current draw, no noise hum or vibration, and no cold! Pretty tough to diagnose over the internet, but I was thinking either AC/DC relay or inverter... Am I close? Is there one common point of failure that might result in these symptoms? Should I even think about repair, or should I consider the Engel 35... looks to be a direct replacement at about half the current draw???Thanks,LarrySail-La-Vie

 

[Richard Kollmann]

Nocold operates on AC but not DC

When a Norcold operates on AC but not DC it is cost effective to repairable. The circuit breaker is sometimes hard to find it may be on the thermostat or near the bottom of the cabinet. Look for a small red button. Check the voltage through the thermostat and circuit breaker. If it is less than 10 volts, the compressor will not run.When there is 12 to 15 volts to the power control box the problem is isolated to one of the following inside the control box – the switchover relay, the inverter oscillator or the 12 volt side of the transformer.The complete control box is removable a new one costs $325 to replace, but you can easily change the units inside.WARNING Do not connect 12 volt power to the control box unless the compressor is connected as you will damage the DC to AC inverter.