Does Pelican adjust an outside damper based on fan speed?
If you have a Pelican PEARL controlling the outside damper position:
Yes, as the fan speed changes, the PEARL will adjust the outside damper position to continue to provide the minimum ventilation rate. For example, as the fan run’s slower the outside damper will be opened further than when the fan is running fast.
If you have a Pelican Z8 or Z24 controlling the outside damper position:
Yes, as the fan speed changes, the Z8 or 24 will adjust the outside damper position to continue to provide the minimum ventilation rate. For example, as the fan run’s slower the outside damper will be opened further than when the fan is running fast.
PEARL configuration options and meanings:
The PEARL will only adjust the outside damper based on fan speed if its configuration called Variable Speed Fan is set to On. Under this configuration you can set in the PEARL what the fan speed will be at for the different HVAC stages (heating, cooling and fan only).
The fan speed configurations for each HVAC stage is set as a percentages from 0% to 100%.
Note: You will want to enable Variable Speed Fan and set the fan speeds even if the PEARL is NOT controlling the fan speed directly. These configurations tell the PEARL that there are fan speed changes.
Variable Speed Fan Settings:
Note: The number of fan speed settings under Variable Speed Fan automatically adjusts based on how many stages of heating and cooling the thermostat is configured for. Here are the available fan speed settings:
Cool Fan Speed – Stage 1: Tells the PEARL what the fan speed should be when 1st stage cooling is enabled.
Cool Fan Speed – Stage 2: Tells the PEARL what the fan speed should be when 2nd stage cooling is enabled.
Heat Fan Speed – Stage 1: Tells the PEARL what the fan speed should be when 1st stage heating is enabled.
Heat Fan Speed – Stage 2: Tells the PEARL what the fan speed should be when 2nd stage heating is enabled.
Ventilation Fan Speed: Tells the PEARL what the fan speed should be when only the fan is enabled.
Note: The number of fan speed settings under Variable Speed Fan automatically adjusts based on how many stages of heating and cooling the thermostat is configured for. Here are the available fan speed settings:
Cool Fan Speed – Stage 1: Tells the PEARL what the fan speed should be when 1st stage cooling is enabled.
Cool Fan Speed – Stage 2: Tells the PEARL what the fan speed should be when 2nd stage cooling is enabled.
Heat Fan Speed – Stage 1: Tells the PEARL what the fan speed should be when 1st stage heating is enabled.
Heat Fan Speed – Stage 2: Tells the PEARL what the fan speed should be when 2nd stage heating is enabled.
Ventilation Fan Speed: Tells the PEARL what the fan speed should be when only the fan is enabled.
The PEARL is controlling the fan speed and outside damper:
If the PEARL is controlling the fan speed and the outside damper, the percentages configured in the Variable Speed Fan configuration will directly correlate with the output the PEARL places to the fan speed input on you HVAC unit. The range of 0% to 100% is equal to the output being 0Vdc to 10Vdc from the PEARL.
The HVAC unit is controlling the fan speed, but the PEARL is controlling the outside damper:
Even though the PEARL is not directly controlling the fan speed, you still needs to set Variable Speed Fan to ON and set the different fan speeds into the PEARL. This tells the PEARL what the fan speeds will can and that it needs to adjust the outside damper based on these fan speeds.
What do I set the Minimum Damper Position to on the PEARL when there are multiple fan speeds?
The Minimum Damper Position should be set so that when the fan is at the fastest speed the amount of ventilation being provided is to ventilation code.
Z8/Z24 configuration options and meanings:
The Z8/Z24 will only adjust the outside damper based on the static pressure targets resets. There are two configurations: Target Operating Static and Target Circulation Static.
Static Pressure Targets:
Target Operating Static: This is the supply duct static pressure the Z8/Z24 will target during a heating or cooling cycle.
Target Circulation Static: This is the supply duct static pressure the Z8/Z24 will target during a fan only cycle.
What do I set the Minimum Damper Position to on the Z8/Z24?
The Minimum Damper Position should be set so that when the Z8/Z24 is controlling the supply fan to maintain the Target Operating Static, the amount of ventilation being provided is to ventilation code.