*LCU Two-Speed Fan RTEM Economizer Minimum Position Handling
Due to the low and high speeds of the indoor fan, when the unit is in Fan Only, Cool 1, or Economizer Only modes the control will require the setting of two economizer minimum positions. The economizer minimum position that will be utilized while the supply fan is at low speed will be set with the RTEM DCV minimum position pot (0-100%) and the minimum position that will be utilized while the supply fan is at high speed will be set with the RTEM building design minimum position pot (0-50%). If the building design minimum position is set to be higher than the DCV min position, the setpoints will be capped at the DCV min position, and the setpoint for the min position at low and high fan speed will be the DCV min position.
1. Apply power to the unit.
2. Using the service test guide on the unit access panel, momentarily jump across the Test 1 and Test 2 terminals on LTB1 one time to start the indoor fan.
3. Turn the MIN POS - DCV potentiometer on the RTEM clockwise to open or counter-clockwise to close. The damper will open to this setting for low-speed fan operation. When adjusting the minimum position, the damper may move to the new setting in several small steps. Wait at least 15 seconds for the damper
to settle at the new position. The range of damper for this setting is 0-100%.
4. Momentarily jump across the Test 1 and Test 2 terminals on LTB1, to cycle through test modes to the highest Cool setting.
5. Turn the MIN POS - DESIGN potentiometer on the RTEM clockwise to open or counter-clockwise to close. This will set the minimum damper position at maximum fan speed. The range of damper for this setting is 0-50%.
6. The economizer minimum damper position for all fan speeds is complete. The RTEM will control the minimum damper position along an imaginary line between the 3 damper minimum positions based on fan speed.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.