Can a Pelican thermostat control three fan speeds?

If there are fixed fan speeds (high, medium, and low), then No.
If there is a VFD or ECM with a 0 - 10 VDC control input, then Yes.

For fixed fan speeds, the configuration options are:

Pelican has found that controlling just the Low and High fan speeds provides all the control needed to maintain a proper room temperature. Here are the configuration options:

1 (default): The thermostat will only use (G) to enable the supply fan.

2: The thermostat will use (G) for low speed fan and (Y2) for high speed fan.

When does the thermostat switch between Low and High Speed?

The thermostat treats the fan speeds like ‘stages’, where low speed is quiet, but cools or heats the room slower and high speed fan is louder, but cools or heats the room faster. Therefore, when the room is in Low cooling or heating demand, the fan will automatically be placed in low speed and when the room is in High cooling or heating demand, the fan will automatically be placed in high speed.

This algorithm also means that the thermostat works to run the low speed fan that majority of the time and only enables the high speed fan for periods where there is higher than normal heating or cooling demand.

For VFD or ECM with 0 - 10 Vdc control inputs, you will need a Pelican PEARL to adjust the fan speed.

The PEARL provides up to 5 fan speeds and adjusts them based on the active cycle. Here are the configuration options:

Cool Fan Speed – Stage 1: This tells the PEARL what the fan speed should be when 1st stage cooling is enabled.

Cool Fan Speed – Stage 2: This tells the PEARL what the fan speed should be when 2nd stage cooling is enabled.

Heat Fan Speed – Stage 1: This tells the PEARL what the fan speed should be when 1st stage heating is enabled.

Heat Fan Speed – Stage 2: This tells the PEARL what the fan speed should be when 2nd stage heating is enabled.

Ventilation Fan Speed: This tells the PEARL what the fan speed should be when only the fan is enabled.