ACCX Air Conditioning

Transcription

1 ACCX Air Conditioning CMR Electrical Ltd Bolton House Five Chimneys Lane Hadlow Down East Sussex TN22 4DX Tel: Run / Stand-by changeover Controller Installation and operation Manual 1

2 Two Air conditioning Changeover Unit The unit consists of two volt free contacts (Start/Stop AHU1 & 2) and will control both AHUS. Both contacts are normally closed, this allows a failsafe for when the unit is powered down or becomes faulty as both AHUS will start. In normal operation the Run AHU volt free contact will be closed (relay deenergized) and the standby AHU volt free contact will be open (relay energized). Both AHUS will need to supply an individual control interlock through the units control relays. Three fault inputs are provided, AHU1, AHU2 and Room over temperature TEMP. A four way selector switch has been provided within the unit to allow the individual fault signals to be set at normally open or normally closed. Any combination of normally open/closed can be set by this switch, i.e. AHU1 normally open (close in fault), AHU2 the same and Room over temperature normally closed (open in fault). This switch is located on the left hand side of the main PCB just above the terminals marked RS485. Identification numbers on the switch relate to, 1 = AHU1 is a normally open input when the switch is pushed to the far left or normally closed when pushed to the far right, 2 = the same but for AHU2 and 4 = the same but for Room over Temperature (switch 3 is unused). The control unit will provide a 12vdc signal to all the remote fault contacts which should be volt free. A common alarm relay is provided which again will be energized in normal operation, de-energize in alarm. Again, this allows a failsafe for when the unit is powered down or becomes faulty as it will start a remote alarm if fitted or signal a fault to the BMS due to power failure. The unit has been designed to control two air handling units and allows one unit to provide heating / cooling with the second unit being off and in standby. After a time delay which is user selected between 1 and 999 hours, the run unit will stop and the standby unit will start up. This feature allows even ware of both AHUS. In the event of a fault developing with the run unit, the system would automatically shut down the run unit, start the standby unit, give an audible warning (requiring a Mute to stop) and operate the common alarm relay. The system would remain in this configuration until the faulty AHU had been rectified and the Reset push button operated. Having changed as described above to the standby unit, if a fault developed with the standby unit i.e. both AHU1 and 2 faulty, both AHUS would start. This has been done in an endeavour to obtain some heating / cooling from both units whilst waiting for repair. If a fault developed with the standby unit, the system would inhibit automatic transfer after the preset time delay, start the audible warning and operate the common alarm relay. Again, if during this configuration the run unit became faulty, both units would be started as described above. On over temperature fault signal has been provided which would be connected to a standard thermostat within the room. If the thermostat detected an over temperature within the room, the system would start both AHUS to give the maximum cooling to the room. Again, the system would remain in this configuration until the Reset push button was operated. A non volatile memory store has been used within the unit to hold the Time between automatic changeovers and the time until the next changeover. In the event of power failure both time periods would remain held within the unit so that on re-powering the time delay to the next changeover continues from where it stopped i.e. on power down it was 63 hours to the next changeover, on re-powering up of the system it will still be 63 hours to the next changeover. Three push buttons are provided Mute to stop the audible warning device, Reset to revert the system back to normal operation after a fault and Set used to manually select which unit is to be run unit or change the time period between automatic changeovers. A timer is activated when entering the Set mode which will automatically revert the system back to normal operation if a push button has not been operated within 10 seconds. All events are displayed in a back lit 16 character 2 line alpha numeric display. 2

3 In Normal Operation With the system up and running without any faults and AHU1 selected as the run unit the display will show the following. AHU1 is Running Time run 030 hrs The display shows that AHU1 has been selected as the run unit and has been running for 30 hours. Relay Start/Stop AHU1 will be de-energized (contact closed) and relay Start/Stop AHU2 will be energized (contact open). A few seconds later the display will change to the following. AHU2 in Standby C/Over in 136hrs This shows that AHU2 is the standby unit and will become the run unit in 136 hours. Again after a few seconds the display will go back to displaying AHU1 status and continue to cycle through both screens. Once AHU2 becomes the run unit the same display format is used but showing AHU1 in Standby and. The Start/Stop relays would change to AHU1 energized ( contact open) and AHU2 de-energized ( contact closed). AHU1 or 2 is selected as the run unit but becomes fault. The display would change from normal operation to the following. STANDBY AHU HAS BEEN ACTIVATED The run unit would stop, the standby unit would start up, the audible warning device would sound and the common alarm relay would operate. This would remain until the Mute push button were operated when the display would show the following. Standby Running A few seconds later a new screen would display the following. Again after a few seconds the display would change back to the first screen and continue to cycle through both screens. This would remain until the faulty AHU had been rectified when the screens would change to the following. Followed by. 3

4 Even though the faulty unit has been repaired, the system will not allow a transfer back to it until the Reset button had been operated. Whilst in this configuration, the automatic transfer due to time would be inhibited. However once the fault had be rectified and reset, the timer would start from where it had been stopped i.e. fault happened with 63 hours until next changeover, fault lasted 5 hours after reset time to next changeover would be 63 hours. AHU1 or 2 is running but the standby unit becomes faulty The display would change from normal operation to the following. The Standby Unit Is Faulty The run unit would continue to run, the standby unit would be locked out, the audible warning device would sound and the common alarm relay would operate. This would remain until the Mute push button were operated when the display would show the following. Followed after a few seconds by. Again after a few seconds the display would change back to the first screen and continue to cycle through both screens. This would remain until the faulty AHU had been rectified when the screens would change to the following. Followed by. Again even though the faulty unit has been repaired, the system will not allow a transfer back to it until the Reset button had been operated. Whilst in this configuration, the automatic transfer due to time would be inhibited as above. Both AHUS become faulty In the unlikely event that at some time both AHUS be come faulty. The display would change to the following. STANDBY AHU HAS BEEN ACTIVATED 4

5 The run and standby units would both run, the audible warning device would sound and the common alarm relay would operate if not already done so. This would remain until the Mute push button were operated when the display would show the following. All AHUS Faulty A few seconds later a new screen would display the following. AHU2 is Faulty All AHUS Faulty After a few seconds the display would change back to the first screen and continue to cycle through both screens. This would remain until one or both faulty AHUs had been rectified. when the screens would change to the following. Only AHU1 rectified. Followed by. Or both AHUS rectified Followed by. Again, even though both faulty unit had been repaired, the system will not allow a transfer back to it until the Reset button had been operated. Whilst in this configuration, the automatic transfer due to time would be inhibited as above. If only one of the AHUS had been rectified and depending upon weather it was a run or standby unit, the system would display one of the fault screens shown above. This would required a second Reset after the remaining faulty unit were rectified. Room Over Temperature If the room becomes to hot, the system will start both AHUS, start the audible warning device and operate the common fault relay. The display will show the following. 5

6 C/O ACTIVATED BY HIGH TEMP This would remain until the Mute push button were operated when the display would show the following. AHU1 is Running Room over Temp Followed after a few seconds by. Room over temp Again after a few seconds the display would change back to the first screen and continue to cycle through both screens. This would remain until the room temperature fell back to normal when the screens would change to the following. AHU1 is Running Room over Temp Followed after a few seconds by. If again the room became to hot before a manual reset occurred, the display would revert back to both AHUS running and Room Over Temp. The audible warning device would not start again nor would the relays change. Once the room reached the normal temperature, the system will not allow a transfer back to normal running until the Reset button had been operated. Whilst in this configuration, the automatic transfer due to time would be inhibited as above. Manually select which AHU is to be the run unit This feature can only be used when the system is in normal running with no current faults. It allows at any time to manually select which unit is to be the run unit i.e. AHU2 is now the run unit with 100 hours before it becomes the standby. After manual selection AHU2 becomes the run unit with AHU1 as standby. After using this feature the time clock will reset back to the maximum hours before the next changeover. A timer is activated when entering the Set mode which will automatically revert back to normal operation if a push button has not been operated after 10 seconds. First press the Set push button, the display changes to the following. Mute = C/O Time Reset= AHU Duty Press the Reset push button, the display changes to the following. 6

7 S=Save, M=Change Run Unit AHU 2 The display is showing that the current run AHU is number 2. S = the Set push button and M = the Mute push button. Press the M (Mute) push button changes the 2 i.e. AHU2 into 1 i.e. AHU1. More presses of the M (Mute) button will toggle between AHU1 and 2. When satisfied with the selection press the S (Set) push button. The system will change the run / standby configuration, restart the time delay to next changeover and display the normal running screens. Change the time delay between automatic change between run and standby configurations. This feature allows a user to determine the period between changing the run unit into a standby unit. By using this feature twice, an automatic changeover can occur at a specific time on a specific day i.e. Monday at 5pm. However attendance may be required to carry this out. To do this first workout the hours between now and Monday 5pm and set the system up for this time, next on Monday at 5pm use this feature again to set the next changeover to 168 hours. The system will then carry out a changeover every Monday at 5pm. Any time period between 1 and 999 hours can be set i.e. 1 hour to 41 day 15 hours. A timer is activated when entering the Set mode which will automatically revert back to normal operation if a push button has not been operated after 10 seconds. First press the Set push button, the display changes to the following. Mute = C/O Time Reset= AHU Duty Press the Mute push button, the display changes to the following. S=Save, R=Next M= Change 999hrs The display is showing the current time delay between changeovers (999 hrs) S = the Set push button, R = the Reset button and M = the Mute button. The cursor will be flashing over the hundreds number to indicate that this is the number being worked on. Pressing the M (Mute) button will increment the number as shown by the flashing cursor. If no change is required to the hundreds, or you are satisfied with your selection, press the R (Reset) push button to move the cursor to the tens number. Again using the M (Mute) button will increment the number as previously described. pressing the R (Reset) push button once again to move the cursor to the units number which can be change as described above. One more press of the R (Reset) push button will take the system back to the hundreds number. Once you have selected your required time delay press the S (Set) push button. This will save the new time, reset the time until next changeover back to the new time and reset the system back to normal operation. The S (Set) push button can be used at any time. 7

8 Notes Both AHU 1 & 2 must have a volt free contact normaly open or closed to indicate to the unit of a fault within the AHU. The unit providers a 240VAC 8amp normaly closed contacts to start and stop the AHUS An over temperature thermostat can be used to start both AHUS. The contact can be normaly open or closed How to change AHU1and or AHU2 and or Thermostat from normaly open to closed contact arrangment. A small 4 way switch can be found on the far LEFT of the PCB located about 30mm from the bottom of the PCB. For normally Open contacts the relivant switch should be pushed to the LEFT, normaly closed the switch should be pushed to the right. Normaly Closed Contact Normaly Open Contact AHU1 Fault AHU2 Fault NOT USED Thermostat AHU 1 AHU 2 AHU Fault Circuit N/O or N/C Volt Free contact Stop/Start Circuit AHU Fault Circuit N/O or N/C Volt Free contact Stop/Start Circuit Thermostat if required Volt Free Common Alarm Contacts L E N NOT USED AHU 1 FAULT CONTACT N/C COM N/O AHU 2 FAULT CONTACT NOT USED REMOTE THERMOSTAT IF REQUIRED 8 AHU 1 START/STOP AHU 2 START/STOP NOT USED OUTPUT ALARM CONTACTS 230VAC Mains Input "L" = Live, "N" = Neurtal, "E" =Earth

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