To: Cell Technicians and Service Contractors responsible for installation and repair. 

Subject: Configuring 2 AIRSYS Lead Lag Controllers for sites with 3 WPUs.

Associated Products: Controller models ASLLC.2A and ASLLC.2A.48. All CAT5 equipped WPUs. 

Background: 3 unit configurations require two AIRSYS Lead/Lag Controllers to operate. For optimal efficiency and reliability, system runtime should be distributed among all three units by configuring one controller for single unit operation.

 

Instructions:

 

I. Place the indoor temperature sensors (rt1) for both controllers at the same location. Care should be taken to ensure that supply or exhaust air is not blowing directly or indirectly (reflected) at the sensors.


II. On the single unit controller, verify that the WPU is wired to the controller using two ethernet cables connected at the top two ports (Figure 1).

                Figure 1


III. On the single unit controller, change “System Number” from 2 to 1 


  1. On the PLD, Press Up and Down together (Figure 3) to return to the main menu. The indoor temperature should be displayed.
  2. Press Up to scroll to Set.
  3. Press Down and Sel together. The screen should display a flashing 0. If not, return to step 1.
  4. Press Sel, the screen should display Stp.
  5. Press Down until SYS is displayed. Press Sel. The screen should display 2.
  6. Press Down to change 2 to 1. Then press Sel to confirm.
  7. Press Up and Down together to return to the main menu.

                                Figure 2


IV. Open the single unit controller box and disconnect the pLAN cable (J6) on the controller module labelled HVAC 2 (Figure 3). After disconnecting the pLAN cable, restart the controller by turning off the QF1 breaker (lower left section of controller box) and turning it back on after 10 seconds.

                                               Figure 3


V. Change the lead offset on the single unit controller

  1. To evenly distribute runtime between all three units, the lead offset on the single unit controller should be changed to 4°F by the following steps:
  2. Press Up and Down together to return to the main menu if it is not already displayed.
  3. From the main menu (indoor temp display) press Up to scroll to Set.
  4. Press Down and Sel together. If done correctly, the screen should display a flashing 0. If not, return to step 1.
  5. Press Sel, the screen should display Stp.
  6. Press Down until C02 is displayed. Press Sel. The screen should display 2.0.
  7. Press Up to increase the lead offset to 4.0. Then press Sel to confirm.
  8. Press Up and Down together to return to the main menu.

VI. Verify indoor temperature readings and calibrate if necessary

  1. On both controllers, press Up and Down together to return to the main menu. The indoor temperature should be displayed.
  2. Verify that the indoor temperatures (main menu) displayed on both controller screens are within 0.5°F of each other. If this is the case, no further action is needed. Otherwise, proceed to step 3 to calibrate the single unit controller.
  3. On the single unit controller, press Up to scroll to Set.
  4. From Set press Sel, the screen should display Stp.
  5. Press Down until n2A is displayed, then press Sel to display the current calibration (default 0).
  6. Press Up or Down until the desired calibration is achieved, then press Sel to confirm. The calibration offset directly correlates to the temperature reading, meaning that an offset of +1.0 will increase the temperature reading by 1.0 °F/C depending on the temperature unit settings. Sample calibrations are given below.

Sample Calibrations:

Example 1. If the two unit controller displays a room temperature of 70°F and the single unit controller displays 71.2°F, the calibration value (Step 6) on the single unit controller should be decreased by 1.2 from the existing value (default 0). The single unit controller should then display a room temperature of 70°F.

Example 2. If the two unit controller displays a room temperature of 75°F and the single unit controller displays 72°F, the calibration value (Step 6) on the single unit controller should be increased by 3.0 from the existing value (default 0). The single unit controller should then display a room temperature of 75°F.


VII. Verify temperature setpoint and change if necessary

  1. Ensure that the main setpoint on both controllers is the same (Default 79°F). To verify the setpoint, perform the following steps:
  2. Press Up and Down together to return to the main menu. The indoor temperature should be displayed.  
  3. From the main menu (indoor temp display) press Up to scroll to Set.
  4. Press Sel, the screen should display Stp.
  5. Press Sel, the screen should display the current setpoint (Default 79°F). If the setpoints on both controllers are the same, no further action is required. Otherwise, proceed to step 5.
  6. Press Up or Down until the screen displays the desired setpoint and press Sel to confirm the new setting, the screen should display Stp.
  7. Press Up and Down together to return to the main menu.

 

VIII. Average temperature sensor readings (Optional)


For sites utilizing hot and cold aisle containment averaging multiple temperature sensors may be necessary for the controller to have an accurate picture of the overall site temperature.The 5 analog input points (all ASLLC temperature sensors are analog resistive type) are individually monitored but can only accept one input each. To average the indoor temperature inputs (rt1), 4 sensors can be wired in a network as shown below.

                                                                            Figure 4


For more information on setting up multi-controller systems, refer to the AIRSYS white paper which can be found at https://support.airsysnorthamerica.com/solution/articles/6000137904.


For questions, contact AIRSYS support at 855-874-5380 or ASNSupport@air-sys.com.


For a list of available training courses, go to https://airsysnorthamerica.com/webinars