Adjusting the Proportional Thermostat

Adjusting the Proportional Thermostat

The proportional thermostat is sold in three configurations: by its self, in the IncuKit™ DC, and in the 225W IncuKit. In all of these configurations the Proportional thermostat operates in the same way; reducing the power to the heating elements as the temperature approaches the desired level or set point but not fully cutting off the power (for proportional vs. standard thermostats click here). This provides a more precise temperature range than a standard electronic on/off thermostat. However, the proportional thermostat’s factory settings sometimes do not produce the desired temperature range. Most often this is because these products are used in different configurations of homemade incubators that have many different factors such as size, shape, insulation, and location to mention a few. This is why it impossible to have a single or even several settings that fit all situations; as a result it is sometimes required for the user to adjust the thermostat settings to obtain the optimal performance for their specific application. The best method for adjusting the thermostat is by making small adjustments one setting at a time, documenting the changes, and then waiting for a period of time to see if the changes produced the desired effects. There are four settings that control the operations of the proportional thermostat which are:

Set Temperature (Set Temp*)- This is the target temperature of the incubator. Adjusting this setting will move the temperature up and down by 0.1 degree increments. If you hold the UP or DOWN buttons down, it will change more rapidly. NOTE: the temperature sensor on this device is VERY sensitive and will adjust very rapidly to tiny changes in temperature. You may see the temperature display moving by several 10ths of a degree above or below the set point and then go the other direction. The sensor is quickly communicating with the controller and adjusting the amount of power that is sent to the heaters. The temperature variation that your eggs will experience is MUCH, MUCH less than the sensitive sensor is reading.

Control Offset (Ctrl Ofs*)- This changes the temperature point where the heater will begin tapering down in power. Depending on your configuration, you may find that the temperature does not get up to an average temperature that is close enough to the set point. This could be due to the size of your incubator or the insulation that is used in your incubator. By adjusting this value up, it can help get the average temperature closer to the set point.

Control Range (Ctrl Rng*)- This changes the temperature range that the decreasing heater slope will be applied to. This means range is where the heater power begins to decrease and goes to zero. For example, if your control offset is 90 degrees and your control range is 12 degrees, the power to the heater will begin to decrease at 90 degrees and will completely cut off at 102 degrees. It is important to makes sure that the control range goes beyond your set point. To do this, simply add the control offset and the control range and if the number is larger than the set point the thermostat should function properly.

OSP Slope (OSPslope*)- This changes the percentage of total power that the heater will receive after the set point has been reached. For example, if the OSP slope is 0.25; once the heater reaches your set temperature the power to the heater will drop to 25 percent and gradually decrease until the temperature reaches the top of the control range. * The setting in the thermostat menu

Before any changes are made it is recommended to allow the incubator to stabilize with the factory settings to determine whether they are sufficient. Also, when making changes to the thermostat settings we recommend only changing one setting at a time in this order: control offset, OSP slope, and finally the control range. Making changes to multiple settings at a time makes it difficult to determine which setting is doing what to the performance of the thermostat.

Many customers would like a specified range that the proportional thermostat should optimally operate in. If every application was identical this would be possible. One of the keys to incubating eggs is that the internal temperature of the eggs changes much slower than the air temperature inside the incubator. This is what makes the average temperature an important number to focus on because it will closely reflect the internal temperature of the egg. This fact makes the best way to determine if the thermostat is functioning correctly by how well it maintains the correct average temperature.

Getting the thermostat adequately adjusted can be a tedious task but once it is done it will make a significant difference in the quality of the performance.