Improving Performance on an old AB
An AB in a four cubic foot box even with poor insulation in NY State will make ice cubes, so there is something wrong. Check the condenser to see that it is clean with no dust on intake side. If the fan is out front it must be moved aside to gain access to the air intake. On older units the fans were mounted behind the condenser without a fan shroud to provide positive air flow through the coil. If the fan is not shrouded use small pieces of foam to close the three open areas, to force air to come through the coil. This is pictured in my 12 volt book or go look at how the fan shroud in your car draws all the fan’s air through the radiator The thermostat may be cycling off too soon. Your unit has a two wire plug on the thermostat wire six inches away from the compressor module. Unplug the thermostat and place a jumper across the short cable. With the thermostat bypassed the box will get much colder, if the thermostat is the problem. If it turns out that the thermostat is the problem e mail me and I will give you instruction on how to adjust it or see the section of thermostats in the book if you have one. Very few people know how to service these units with refrigerant. But you can get a ball park idea if the refrigerant charge is good enough to make ice cubes. On these thin plate cap tube evaporators a film of frost must cover 100% of the evaporator to indicate there is enough refrigerant. Overcharge with refrigerant is indicated by frost returning on the refrigerant lines outside the box. Two ounces of extra refrigerant in this system can double the daily amp-hrs and provide very poor performance.
