ELECTRONIC AIR CONDITIONING CONTROL

1 ELECTRONIC AIR CONDITIONING CONTROL TH-T500 Simplified Driver s panel TH-T505 Complete Driver s panel TH-T510 Control box THERMOBUS INSTRUCTION MANUAL FOR OPERATOR PHONE: +39 035 4997266 FAX: +39 035 4997473 December 2005 / Rev.C Software version of panel TH500: from 1.5 Software version of panel TH505: from 2.2 Software version of control box TH510: from 2.0

2 INDEX 1) INTRODUCTION...3 2) DESCRIPTION OF THE SYSTEM S ELEMENTS...4 2.1) Display TH500...4 2.2) Display TH505...5 2.3) Control Box......6 2.4) Speed regulator...7 2.5) Motorized water valve...7 2.6) Air temperature probes...8 3) FUNCTIONS FOR BOTH PANELS (TH500 + TH505)...9 3.1) Selected temperature...9 3.2) Full AUTO mode...9 3.3) Evaporator fan speed...10 3.4) Air conditioning...11 3.5) Convectors...11 3.6) Reheating...12 3.7) Defrost...12 3.8) Fresh air/recycle...12 4) FUNCTIONS REGARDING ONLY THE TH505 PANEL.....13 4.1) Pre-heating...13 4.2) Clock adjustment...13 4.3) Pre-heater timer adjustment...14 5) SERVICE OPERATIONS TEST MODE...15 6) VISUALIZING AUXILIARY DATA...17 7) FAULT CODES...18 8) OPERATIONS WITHOUT PANEL...19 9) CONNECTIONS BETWEEN PANELS AND CONTROL BOX...20 10) ELECTRIC WIRING CONNECTION EXAMPLES...22 10.1) Standard bus...22 10.2) Double decker bus...24

3 1) INTRODUCTION The Thermobus climate control system is made up of a control panel (TH500 and/or TH505) and two or more control boxes which receive indications and send signals to the various elements of the system; the control panel and control box are connected with a Half Duplex communication wire. For standard buses the control panels are alternative (the TH505 model has more functions). For the double decker with front box the TH505 panel is prevalent and controls the upper deck as well as the driver area, whereas the TH500 panel controls the lower deck. The system has different probes that detect the external temperature, the internal temperature (placed on the roof above the passengers) and mixed air temperature (which is placed in the treated air-delivery channel) To be able to reach and then maintain the temperature set by the operator, the system uses the values detected by the three probes and intervenes on the following elements: - the state of the refrigerant passage valve on/off - the state of the compressor on/off - the evaporator fan speed (from 1-6 via a speed regulator) - the state of air-intake flap (if there is one) - the hot water carriage to the evaporator via a partialising valve - the water passage valve (can be partialising or on/off according to the type of system) to the supplementary heating (convectors or unit heaters) - the state of the heating water pump Furthermore, the panel has a manual pre-heating ignition as well as a timer. Its other functions will be explained further on.

2) DESCRIPTION OF THE SYSTEM S ELEMENTS 2.1) Display TH500 4 The screen (display) is made up of two digits (numbers or letters) which indicate the desired temperature or the external one as well as the fault codes and the parameters. 1) key to selcet passenger control, driver area and to visualize external temperature 2) led on driver control 3) led on passenger control N.B.led 2 and 3 on visualizing external temperature 4) increase key 5) decrease key 6) manual ventilation 7) AUTO key 8) led on: ventilation is on manual mode and not automatic 9) led off: all functions on automatic mode 10) manual open/close of recycle flap 11) led on: air intake flap is closed therefore air reycle is functioning 12)driver air distribution flap 13) led on: upper air flow See paragraph for electrical wiring diagrams

5 2.2) Display TH505 The screen (display) is made up of two digits (numbers or letters) which indicate the desired temperature or the external one as well as the fault codes and the parameters. 1) Supplementary heating (convectors or unit heaters) 2) Windscreen demystifier 3) Increase key 4) Decrease key 5) Key to swap from passenger control to driver control: led on driver function 6) Pre-heating 7) Visualize external temperature 8) Fan speed selection (manual) 9) AUTO mode 10) Air-recycle 11) Swap from air going to driver s feet/ windscreen (where foreseen) See paragraph for electrical wiring diagram.

6 2.3) Control Box The control boxes are situated near the current source of the system. This applies to both the passenger area as well as the front box. Each control box controls all the elements of the micro climate. Therefore, if you have to check the driver and passenger area separately, two control boxes are needed. The control box has 4 green leds and two red ones. The four green led show the activation of: 3) convectors 4) water pump 5) evaporator fan speed 6) compressor clutch coil When the red led (1) is flashing it indicate the correct communication of the signal. The led (2) indicate that the signal is for the passengers zone or for the driver one (if it is switch on or off). See paragraph for electrical wiring diagram

7 2.4) Speed Regulators All the Thermobus air-con systems have speed regulators. These work at a 6 phase increase. This allows for an optimum air - delivery regulation. Diagram for connection of the Thermobus regulators. 2.5) Motorized water valve This valve, also called partialising valve, allows for a flux of hot water to the evaporators (or supplementary heaters) which is proportional to the amount of heat requested by the system so that it can reach the selected temperature. The motorized water valves are subject to a functioning cycle (total opening and closing) whenever the vehicle is turned on. Connection of valve connectors 1) POT1 2) POT2 3) mass 4) signal 5) n.c. 6) signal

8 2.6) Air temperature probes The system has three types of probes: 1) Internal air probe The internal air probes detect the temperature in the passenger and driver area. The greater the difference between the detected temperature and the selected one, the greater the quantity of treated air introduced into the bus. They have a suction air vent to be able to read the temperature better. The internal probes are generally situated on the roof above the passengers, in the centre of the bus. They are usually hidden by a disc cover. They are connected to the control box by 3 wires: two of which regard the signal and one specifically for the current supply of 12V. 2) External air probe If the system has a roof air conditioner, the probe is placed on top of the roof in a protected area. Otherwise it is positioned outside the bus in a ventilated area. It is connected to the control box by 2 wires (signals).

9 3) mixed air probe It is placed in the treated air channel and signals the temperature of the incoming air, influencing the climate. As for the internal air probe, there is also only one mixed air probe for each micro-climate (passenger and driver area). It is connected to the control box by 2 wires (signals). 3) FUNCTIONS 3.1) Selected temperature The selected temperature is the desired temperature that you wish to reach. To modify it just press or. By pressing the key until it reaches the maximum value, (high temperature) will appear on the display. This function indicates that the expansion valve remains closed whilst the valve that controls the flux of hot water to the evaporators and the supplementary heaters remains fully open. By pressing the key until it reaches the minimum value,.(low temperature)will appear on the display. Here the maximum flow of refrigerant is requested. This means that the compressor is on and the expansion valves are open. 3.2) Full AUTO mode By pressing the key you can enter into the automatic climate control. The panel shows the selected temperature and the system starts working by making use of all the elements available to reach that temperature (ventilation, air-conditioning and/ or heating) together with the signals it receives from the internal, external and mixed air temperature probes.

10 As far as the climate and heating is concerned, the system uses a very precise algorithm to create maximum comfort conditions inside the bus compartment. The graph below can help you understand the logic used. In the first part of the graph, if we read from left to right, we are in the condition where the internal temperature is higher than the desired one (set point), therefore the compressor is on. As you can see, as the system reaches the set point, the heating starts working. This happens so that the temperature coming out of the evaporator is as close to the desired temperature as possible. On the bus it is possible to obtain the maximum comfort using both the air-conditioning and heating at the same time. The compressor stops working when the system s internal temperature reaches 2 C below the set point. It starts working again once the system has overtaken the set point. When checking the temperature of the heating system, the air recirculation flap stays open. If the driver wishes to close it manually, he can. 3.3) Evaporator fan speed When AUTO mode is selected, the fan speed is controlled in function of the difference between internal temperature and selected temperature. The larger the difference between these two, the faster the fan speed. This is done to enable the climate to reach the desired conditions as rapidly as possible. As the temperature starts reaching the set point, the fans gradually slow down. The panel allows for the manual functioning of the ventilation whilst all the other functions continue working automatically. To do this press and on the display the fan speed preceded by the letter u will appear. Therefore from u1 to u6. When the fan speed is

11 controlled manually the led switches on. To go back to the full auto mode, keep the pressed for three seconds; the led turns off and the system is controlled automatically. key When manually controlling the ventilation, the air recirculation flap opens. To close the flap simply press the key. 3.4) Air conditioning The air conditioning works as shown in auto control graph. The elements function in the following way: - Compressor and condenser fans: The compressor clutch is inserted automatically according to the temperature values detected and the desired temperature inside the bus. The clutch and condenser fans are inserted simultaneously. There is a fixed time lapse of 60 seconds between one insertion of the compressor and another so as to protect the compressor. - Pressure switches The control box receives a signal from the high pressure and low pressure switches. At any point where the pressure is abnormal, the clutch is released due to the intervention of the pressure switches and the display will read. This symbol will remain flashing for three minutes, after which the clutch is inserted once again. The Thermobus climate systems usually have an intermediate pressure switch which reacts according to the pressure detected and then activates the functioning of all or only a part of the condenser fans. 3.5) Convectors The supplementary floor heating (convectors) intervenes only in the case of high negative differences between the internal and selected temperature. The passage of water is controlled by a proportional valve which allows the flow of the correct amount of fluid in relation to the internal, external and desired temperature. In the AUTO mode the convectors are inserted in these conditions: - external temperature lower than 15 C - difference between the internal and desired temperature higher than 8 C. In AUTO mode the convectors are released when the internal temperature reaches -6 C compared with the set point. The convectors can be inserted manually. With the TH500 panel press the key for 3 seconds, whilst the TH505 panel has two keys which are dedicated to this function the key, of which one for the convectors in the passenger area and the other for a possible heating unit in the driver area. In both cases the symbol Cn appears on the display. The manual control doesn t take the external temperature into consideration and the convectors continue working up until -2 C below the selected temeparture. To release the convectors press the key again for three seconds for the TH500 panel and the corresponding key for the TH505 panel.

12 3.6) Reheating This function allows you to insert the compressors even if it isn t required by the AUTO mode. To activate the REHEAT function press for 5 seconds. The heating must be on and the external temperature must be less than 7 degrees C. If the temperature is lower than 7 C Lt appears on the display. When you activate REHEAT, on the display you will see Rh alternating with the selected temperature. The following elements intervene on the system: - Water valve open at pre-set level (default 100%) - Intervention of the compressor All the other elements continue functioning automatically. The set time for REHEAT is 300 seconds. If you wish to stop the function press for 5 seconds. When REHEAT is deactivated the water valve goes back to its previous state. 3.7) Defrost This function is used to demist the driver s windscreen. The fans work automatically at maximum speed and the water valve opens completely. To activate this function with the TH500 panel press both the and keys together for 3 seconds. For the TH505 panel the following key On the display the symbol de appears. is dedicated to this function. The defrost function stops automatically after a time lapse of 60 seconds. 3.8) Fresh air/recirculation The system has one air recirculation flap control for the air in the passenger area and one for the driver area. The recycling of air works both automatically and manually. In automatic: - when the internal temperature is close to the set one, the functioning of the flap is controlled by a series of parameters which allow it to open and close periodically. This is done to maintain the selected temperature and the necessary air renewal inside the bus. - if the internal temperature is very different from the desired one, the flap stays closed to help the system approach the desired temperature as rapidly as possible. You can also control the flap manually by pressing the led switches on automatically.. In this case the corresponding

13 When the recycle opens, it closes automatically after the time lapse indicated by the parameter. This done in case the driver forgets to close it. 4) FUNCTIONS RELEVANT ONLY TO THE TH505 PANEL 4.1) Pre-heating It is possible to activate the pre-heating both manually, using the corresponding,key, as well as with the programming of ignition time within the following 24 hours. When the ignition is programmed, the pre-heating will work for 60 after which it switches off; the programming remains in the software s memory also for the following 24 hours. The programming of the ignition of the pre-heating is highlighted by a flashing red led at the bottom right hand side of the display. 4.2) Clock adjustment 4.2.1) Hour adjustment Press the key for about 4 seconds, after which you will see appear on the display. Press to enter and with the or adjust the value. After having adjusted press to go back or to exit the clock adjustment function. 4.2.2) Minute adjustment Press and on the display you will see, press to enter and with the or adjust the value. After adjusting press to go back or to exit the clock adjustment function. 4.2.3) How to visualize the seconds Press and on the display you will see, press to visualize. Afterwards press to go back or to exit the clock adjustment function. N.B.: The seconds can only be visualized and NOT adjusted.

14 4.3) Pre-heating timer adjustment 4.3.1) Hour adjustment Press key for about 4 seconds, after which you will see, appear on the dispaly. Press to enter and with the or keys adjust the value. After adjusting press to go back or to exit the Pre-heating adjustment function. 4.3.2) Minute adjustment Press and will appear on the display. Press to enter and with the or keys adjust the value. After adjusting press to go back or to exit the Preheating adjustment function. N.B.: The seconds cannot be adjusted. 4.3.3) How to cancel the pre-heating function To cancel the pre-heating function press for about 4 seconds, after which, will appear on the display, press to enter and then or until.appears on the display. After adjusting press to go back or to exit the Pre-heating adjustment function.

15 5) SERVICE OPERATIONS TEST MODE In this section it is possible to visualize le service operations. Here you can verify all the input and insert some output signals on the control box. To enter this mode proceed as follows: Press the + + keys all together. On the display will appear. At this point insert the password. Its value is. Use the and keys to visualize the correct value. Press to confirm. In this case if the password is incorrect, the panel goes back o showing the selected temperature. If instead the password is correct, you will see i. appear on the panel. Now it is possible to visualize the input. Press to scroll through input and output. Press on the requested information. o will appear on the panel if you have selected input or output. If we are dealing with input, the RECIRCULATION indicates its state. If the key is lit this means that the input is inserted. If, instead, it is flashing, the input is not inserted. Whereas, when selecting output, press indicates the state. or switch off the actual output. Here the led Press or to scroll through output and input. When moving from one output to the other the functions remain in their normal state even when exiting this function. If you don t want to leave this mode on, make sure that you switch it off before moving from one function to the other. To quit this mode press twice. INPUT DESCRIPTION Led On Led Flashing Input for lights is on Input for lights is not Input - lights on. Pressure switch Driver control box The two pressure switches are functioning correctly The system has checked the state of the control box One or both are open or else there could be a problem with the connection. The system has not pin pointed the presence of driver control box

16 OUTPUT DESCRIPTION Speed value different from zero Passengers 50% Condensers Clutch (check the pressure switches). Passenger convectors Passenger water pump Passenger air recycle Water valve Speed value different from zero Driver 50% Climate valve for driver area Driver convector Driver water pump Driver air recycle Driver water valve Air distribution CO Gas charge function. Allows the compressor to work without temperature control (internal and external). The pressure swithces are still protected

17 6) VISUALIZING AUXILIARY DATA With the panel it is also possible to check a series of data not immediately shown by the system. To see this data press the and keys together for 3 seconds and then use the same keys to move from one piece of data to the other. To visualize the required information press. Press it again to come back in the menu. To quit this function press. INDICAZIONI DESCRIZIONI Internal temperature in passenger area Mixed air temperature in passenger area Voltage of passenger control box Opening percentage of passenger water valve Software version of the panel Software version of the passenger control box Internal temperature in driver area Mixed air temperature in driver area Voltage of the driver control box Opening percentage of driver water valve Software version of the driver control box

18 7) FAULT CODES FAULT DESCRIPTION Operation with fault External air temperature probe disconnected Internal air temperature probe disconnected Internal air temperature probe open for passenger area The system uses the value = to 0 as temperature reference Short circuit of internal air temperature probe for passenger area. The system uses the value = to 0 as temperature reference Mixed air temperature probe open for passenger area Short circuit of mixed air temperature probe for passenger area. The system uses the value = to 0 as temperature reference Error on the passenger water valve command Error on the driver water valve command Communication fault between the panel and the passenger control box Communication fault between the panel and the driver control box Internal air probe for driver area disconnected

19 Short circuit of internal air probe for driver area Control takes place regarding the Air Return temperature Short circuit of mixed air probe for driver area Mixed air probe for driver area open Pressare switch open Control takes place regarding the Air Return temperature, The clutch is released. After 3 minutes, it tries to re-insert itself. If the problem persists, it is released again and the system continues indicating faulty functioning 8) OPERATIONS WITHOUT THE PANEL When the key is placed in the ignition, the system tries to recognise all its devices. After 15 seconds the system starts working normally. Safety devices In case there are problems with the connection between the panels and the control boxes, on the display the error code will appear if there is problem with the passenger control box and if the problem regards the driver control box. In this condition of anomaly the climate system has a safety device so that it continues working automatically, aiming at the last temperature selected before the system switched off.

20 9) CONNECTION OF PANELS AND WIRING DIAGRAMS 9.1) TH500 List of connections 1 COM (common) 2 GROUND/MASS 3 N.C. 4 COM (common) 5 N.C. 6 N.C. 7 - +24V after ingnition switch 8 N.C. 9 N.C. 9.2) TH505 1 - +24V Battery 2 N.C. 3 COM (common) 4 N.C. 5 N.C. 6 N.C. 7 GROUND/MASS 8 Pre-heating exit 9 N.C. 10 - +24v signal D+ (61) 11 N.C. 12 N.C. 9.3) TH510 CN1 1 Internal air probe 2 External air probe 3 Mixed air probe 4 Pressure switches 5 Internal air probe 6 External air probe 7 Mixed air probe 8 N.C.

21 CN2 1 Key (15) 2 Lights (58) 3 COM (common) 4 GROUND/MASS 5 Battery (30) 6 N.C. CN4 1 Water valve 2 Water valve (POT1) 3 Water valve (ground) 4 Recirculation flap 5 Distribution flap 6 Pulley 7 - +24V key 8 Water pump 9 Water valve 10 Water valve (POT2) 11 - +12V P/internal air probe 12 Recirculation flap 13 Distribution flap 14 Speed different from zero 15 Convectors 16 Analogical exit (evaporator fan speed)