If the warmer evaporator is too cold, the drop in temperature may be due to a bad valve adjustment (too closely adjusted at too low a temperature). To make an accurate adjustment on a two-temperature valve, take the following two steps:
1. Turn the adjusting nut (one-half turn at a time) and allow fifteen minutes between turns. In this way, the evaporator will be given sufficient time to respond.
2. Attach an accurate thermometer to the evaporator and watch the temperature changes until you reach the desired temperature. For more accurate results, instead of using a thermometer, you can connect a low-pressure gauge to the evaporator side of the valve and convert the pressure to temperature. If a gauge opening is not available, install a shut-off valve with a gauge opening.
If the valve is leaky, the evaporator temperature will not rise, in which case the valve must be replaced.
If the valve is stuck shut, the warmer evaporator will never cool and the valve must be replaced.
If the two-temperature valve is installed in or near the freezer compartment, frost will accumulate on the bellows. Remove the valve from the freezer compartment or cover the bellows with a light grease.