B234764 3 Futurair GBa

BOVA Futurair

Fresh air Cooled air

Ventilated air Recycled air Waste air

January 2000 - GB 232257

Heated air

Index Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Assembly drawing of heating, ventilation and airco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Roof unit assembly drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Operation of BOVA FUTURAIR system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Explanation to control unit push-buttons and selectors . . . . . . . . . . . . . . . . . . . . . System description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Emergency on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 5 5 8 8 9 9 9

Trouble-shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control unit error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Explanation to error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WABCO diagnostic controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 10 11 13

Maintenance and repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R134a gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operational mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWM motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Roof unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Water baffle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dust filter or cara filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relays and fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14 14 14 14 14 15 16 16 17 17 17 17 17

Order numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Annex 1: Complete circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Annex 2: Operational form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Annex 3: Operational graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Annex 4: Temperature sensor resistances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Version 3, from chassisnumber 6003370

Futurair

Oktober 1997

1

Introduction The BOVA is equipped with the BOVA Futurair system, which is a fully automatical heating, ventilation and airco(nditioning) system for the passenger seat room. The heating and ventilation of the driver's seat is regulated manually using the front heater. If the airco is integrated, grids in the front ceiling section blow cool air on to the driver's seat. In coaches not equipped with the airco the operation of the system as a whole remains identical. Any differences between ventilation model and airco model will be pointed out.

Futurair

2

Assembly drawing of heating, ventilation and airco 1 2 3 4 5 6 7 8 9 10 11 12 13 14

front heater fan (manual) water cock underfloor heater 1 underfloor heater 2 underfloor heater 3 underfloor heater 4 front water valve rear water valve roof heater water valve preheater preheater water pump stop cocks (3) roof units (2)

15 16 17 18 19 20 21 22 23 25

condenser drier liquid vessel sight glass condenser fans (4) magnetic coupling high-pressure pressostat low-pressure pressostat compressor (with sight glass to rear) spare dynamo (not for Mercedes) PWM-driven fans (4) for underfloor heaters

Futurair

3

Roof unit assembly drawing

24 26 27 28 29 30 31 32 34 35

Futurair

PWM (Pulse Wide Modulation)-driven fans (6) for roof unit heating and evaporation units (2) air valves (2) defrosting thermostat (to the left) expansion valves (2) dust filters (2), with as optional item two cara filter types, with or without carbon coatings (8, 4 on each side) locks (4) adjusting motor for left-hand and right-hand air valves ventilation nipples (2) roof unit water baffles (2)

4

Operation of BOVA FUTURAIR system Control unit

Explanation to control unit push-buttons and selectors Selection of required coach interior temperature in range from about 18NC to 28NC. This range varies along with the outside air temperature. With the selector in its central position, the setpoint may range from about 23NC to 27NC. This setpoint is called the comfort value. Manual raise or reduction (max. 2NC) in AVS-channel temperature set by control unit.

Manual raise (max. 15%) or reduction (max. 10% ) in flow rate, set by control unit, of exhaust air from the nozzles.

Futurair

5

a)

Inquiry after outside air temperature; is displayed for 3 seconds.

b)

Depression for over 3 seconds and simultaneous depression of button 5 results in appearance of 0 on display. Depression of button 4 (-) enables the temperature in the coach interior rear to be set lower than that in the coach interior front. The longer it is pressed, the higher the difference between rear and front (max. reduction is 2NC). Each time the button is pressed, a higher figure appears, preceded by a - sign, and one more block is added on the display. The highest figure possible and the highest number of blocks is 8. On contact disengagement followed by re-engagement the front and rear temperatures are reset to the same value (0).

-8

a) b)

Inquiry after coach interior temperature; first that in the front (8) is displayed and, some two seconds later, that in the rear (9). Depression for over 3 seconds and simultaneous depression of button 4 results in appearance of 0 on display. Depression of button 5 (+) enables the temperature in the coach interior rear to be set lower than that in the coach interior front. The longer it is pressed, the higher the difference between rear and front (max. rise is 2NC). Each time the button is pressed, a higher figure appears, and one more block is added on the display. The highest figure possible and the highest number of blocks is 8. On contact disengagement followed by re-engagement the front and rear temperatures are reset to the same value (0).

Preheater programming. Three different times can be programmed in 24 hours. The preheating period is limited to 60 minutes. On depression of button 6 a 1, 2 or 3 appears on the left-hand display section. Depression of buttons 4 and 5 enables the required engagement period to be set. Once set, the required time can be activated by the user waiting until the display returns to its regular time display mode (this takes about 20 sec.). If programmed, the LED inside the button remains on, which means that only one time can be activated. On depression of the button the activated program is displayed. Continued activation of this time requires another 20 sec. waiting time. Program deletion is possible on depression of button 6 until the LED inside the button goes out. Setting of digital clock, which normally appears on the display, by continued depression of button and simultaneous depression of button 4 (-) or 5 (+).

Manual preheater (dis)engagement. Normally, it is the electronic control unit that automatically (dis)engages the preheater. Depression of this button results in disengagement of the automatic preheater control unit. Operations remain manual until contact disengagement followed by re-engagement. Airco compressor disengagement. On contact engagement the LED inside the button lights up. If required, the compressor can be engaged by the electronic control unit. It is engaged the moment bar 'AC' on the display lights up. On depression of this button the LED goes out, and compressor engagement by the electronic control unit is no longer possible. If the electronic control unit considers the use of the airco necessary, the bar lights up to show that the use of the airco is required for reaching the desired temperature.

Futurair

6

Change-over from inside-to-outside air ratio determined by control unit to 100% inside air, within a fixed period of about 10 minutes. After this period the control unit resumes valve positioning. This feature is applied in such environments as tunnels and car wash lines. Redepression of this button within the same 10 minutes results in a return to automatical positioning.

d) e)

Display: a) 1-2-3: programmed preheater reaction time. b) 'HEAT' bar lights up on activation of underfloor heaters. c) 'AC' bar lights up on activation of the airco or whenever the use of the airco is required for reaching or retaining the temperature setpoint. Whenever the outside air temperature drops below + 3NC, a red bar appears, the outside air temperature is displayed and an acoustic alarm signal sounds for about 5 seconds (warning against 'slippery road'). Display of current time.

Remarks on ventilated coaches: 1) 2) 3)

Futurair

Ventilated coaches are non-airco coaches. Under specific conditions it is impossible to reach the temperatures specified in item 1. Button 9 (AC) is irrelevant for these coaches.

7

System description The purpose of the Futurair system is to reach and retain a preset temperature. The AVS channel continuously supplies sufficient outside air for ventilation. The system comprises three autonomous units, which combine to create the required climate: # # #

heating ventilation airco.

The airco is optional. In coaches not equipped with the airco the operation of the system as a whole remains identical. There are three operation modes: # # #

automatic control of heating, ventilation and airco off emergency on

heating and ventilation 0: auto 1: off 2: emergency

These modes are set by activation of the switch on the central console. Each unit will be discussed separately, although, as stated earlier, in practice they never function individually but invariably combined with one or two other units.

Automatic control Heating For automatical operation of the whole system the switch is set to 0. The desired temperature is set with selector (1) on the control unit. If this temperature is higher than the current coach interior temperature, the heating unit is activated automatically, depending on coach interior temperature, outside air temperature and water temperature. The heat is supplied from both the roof heating unit and the underfloor heaters. The underfloor heaters work on 100% recycled coach interior air, which is taken in through the skirting in the floor. Since the interior temperatures of front and rear are regulated separately, two water valves are mounted, one for the two front underfloor heaters and one for the two rear ones. These valves are not activated until the water temperature is 50NC or more. They are opened more or less wide according to the coach interior temperature. If the temperature in the coach interior front is too low, the front water valve is opened wider. Consequently more hot water is supplied to the two front underfloor heaters, which results in a rise in temperature in the coach interior front. The roof heating unit water valve is permanently active, for prevention of a complete circuit shutoff. The roof heating unit works on a mixture of interior and exterior air. The interior air is taken in through two grids in the rear central ceiling strip. An alternative is to adapt the automatically set temperature manually as follows: 1 Raise or reduce the temperature of the air from the AVS channels by max. 2NC, using selector (2). The underfloor heater air temperature remains unchanged. 2 Slightly raise or reduce the rotation speed of the roof fans, using selector (3). 3 Set temperature in coach interior rear max. 2NC higher or lower than that in the front, using buttons (4) and (5). Preheater Whenever the cooling water temperature is not high enough to heat the coach interior, the preheater is automatically engaged by the control unit, on the basis of data from the various sensors and of the temperature setpoint. The moment the motor has heated the cooling water to 78NC, the preheater disengages itself. The moment the desired interior temperature has been reached, it is disengaged by the electronic control unit. An alternative is manual preheater disengagement. In this mode operations remain manual until the contact has been disengaged. At temperatures over 10NC the preheater is no longer engaged by the electronic control unit. Besides, airco unit engagement results in preheater disengagement.

Futurair

8

Ventilation The ventilation unit works on the same system as the heating unit. With the switch set to (0), the control unit regulates the ventilation fully automatically (in combination with heating unit or airco or both), according to temperature setpoint, water temperature, coach interior temperature and outside air temperature. Ventilation is provided by the roof fans, which inject outside air only or an air mixture, according to these temperatures. With the roof unit air valves pointing up, only recycled interior air is being injected. With the valves pointing down, only outside air is being injected into the AVS channels. Since the valves are usually in an intermediate position, both interior air and outside air are taken in. Only with the smog button pressed, do the air valves point up. Airco The airco is accommodated in the roof unit. Whenever the airco is used, the preheater is off. The airco is active only with the switch set to (0), which means in the automatical mode. If required, it is engaged automatically. It can be disengaged with selector (9) on the control unit. The relays activate the magnetic coupling and the condenser fans. These fans remain active. Whenever the roof unit evaporators threaten to freeze, the magnetic coupling is disengaged. Under normal conditions this must be out of the question because it is impossible to set the exhaust air temperature in the AVS channel lower than 4NC. The defrosting thermostat is engaged at 1NC and disengaged at 4.5NC. Another reason for magnetic coupling disengagement is system overpressure or underpressure.

Off With the switch set to (1) the system is off. The wire for the underfloor heater fan speed signal is connected to earth, for the fans to stop running. The two underfloor heater water valves are shut. Preheater and water pump are disengaged, with only the front heater remaining operable.

Emergency on With the switch set to (2), the heating unit changes over to the emergency mode. The only occasion for its activation is when the temperature in the passenger seat room is no longer under control. The underfloor heater speed signal is disconnected from the system, with the heaters starting to rotate at full speed. The underfloor heater water valves are opened. The roof fans can be set rotating by disconnection of the blue plug behind the ashtray. Then the fans start rotating at full speed. If the plug is beyond the reach of the ashtray, remove the control element using the hooks delivered with the system. The wire colours are violet and white. The roof heater water valve is in the position it was in on disengagement. If heating through the roof channel is not required, the stop valves (D) in the roof unit channel may be shut. If, in an emergency, only the roof fans need to be activated (with floor heating off), pull out the plug behind the ashtray and set the switch to (1) (off). After system repair, remember to reset the switch to (0) (automatical mode) and plug the system in.

General remarks The moment the last swing door is closed, the underfloor heater fans are disengaged and the roof fans start rotating at a very low speed. This is to reduce the overpressure inside the coach and to make the door close more tightly. With the motor off, the speeds of the various fans are low, which results in power saving.

Futurair

9

Trouble-shooting The control unit accommodates a failure analysis facility for easier trouble-shooting. It checks if the various components function properly. If they do not, the display shows an error code (see list below). The coach driver can delete this code by pressing buttons + and - simultaneously. On contact disengagement followed by re-engagement the error code reappears on the display, but only if the failure persists. Error codes for failures that have been eliminated are stored in the unit memory. They can be read from and deleted by the WABCO diagnostic controller (see section on WABCO).

Control unit error codes 0 1 2 3 5 6 7

Test error in control unit parameter memory Interruption or short-circuit between outlet air sensor and control unit Interruption or short-circuit between outside air temperature sensor and control unit Tacho signal Preheater feedback Feedback from engaged water pump Water pump outlet short-circuit

8 9 10 11 12 13 14 15

Short-circuit between water valve and control unit Contact (+/-) between water valve and control unit Short-circuit in right-hand air valve motor Contact (+/-) in right-hand air valve motor Short-circuit in left-hand air valve motor Contact (+/-) in left-hand air valve motor Short-circuit at preheater outlet Short-circuit at outlet of preheater in ECON mode

16 18 20 21 22

Short-circuit at anti-freeze unit outlet Water pump interruption Water valve interruption Right-hand air valve drive interruption Left-hand air valve drive interruption

24 25

Left-hand air valve fails to move to required position Right-hand air valve fails to move to required position

48 49 50 51 52 53 55

Subelectronic control unit fails to respond Test error in subelectronic control unit parameter memory Interruption or short-circuit in front interior temperature sensor Interruption or short-circuit in rear interior temperature sensor No or hardly any contact or short-circuit between magnetic coupling and condenser fans Interruption or short-circuit in water temperature sensor Subelectronic control unit output stage interruption

56 57 60 61

Interruption or short-circuit in outlet air temperature sensor of front underfloor heater No or hardly any contact or short-circuit in water valve of front underfloor heaters Interruption or short-circuit in outlet air temperature sensor of rear underfloor heater No or hardly any contact or short-circuit in water valve of rear underfloor heaters

Note that the functioning of the components with error codes 18, 20, 21 and 22 is checked only on contact engagement.

Futurair

10

If the control unit does not take any action, first check fuses 37 and 38 for power supply to control unit and subelectronic control unit. If these fuses are intact, check if the control unit is plugged in.

Warning! Turn off main switch before unplugging control unit or subelectronic control unit, in order to avoid damage.

Explanation to error codes 0...

Inspection of control unit interior has revealed error. Control unit is due for replacement.

1...

Inspect outlet air sensor in AVS channel. It is accommodated to the right-hand rear and connected to terminals 28 and 35 of the control unit. See annex 4 for resistances of this sensor.

2...

Inspect outside air temperature sensor, which is accommodated behind the right-hand headlamp corner and connected to terminals 28 and 34 of the control unit. See annex 4 for resistances of this sensor.

3...

Check if tacho is connected properly. If so, check if disc is mounted tightly and if tacho works to satisfaction.

5...

First check if preheater is working. If so, inspect wire between terminal 13 of control unit and lead 30 of relay 6. Terminal 13 should be energized with 24 V. If the preheater fails, inspect fuse 17 and relay 6.

6...

Check if relay 5 is activated on preheater engagement and if the pump is working. If so, check if lead 15 on the control unit plug is being energized (leave plug in when preheater is engaged).

7...

Check if lead 26 is connected to earth. If so, inspect lead as far as water pump.

8...

Check if lead 24 or 25 or both contact earth. If so, inspect lead as far as roof unit water valve.

9...

Leads 24 and 25 contact somewhere. Check if they do near plug on control unit and near roof unit water valve.

10..

Check if lead 5 or 6 or both contact earth. If so, inspect lead as far as right-hand air valve motor.

11..

Leads 5 and 6 contact somewhere. Check if they do near plug on control unit, near righthand air valve motor and near wiring.

12..

Check if lead 3 or 4 or both contact earth. If so, inspect lead as far as left-hand air valve motor.

13..

Leads 3 and 4 contact somewhere. Check if they do near plug on control unit, near lefthand air valve motor and near wiring.

14..

Output 20 of control unit short-circuits earth. Check if relay 6 is intact.

15..

Output 21 of control unit short-circuits earth. Inspect wiring from control unit to preheater.

Futurair

11

16..

Output 2 of control unit short-circuits earth. Inspect wiring to buzzer behind central console.

18..

Inspect wiring, from output 26 of control unit to water pump, for contact interruptions. Check if water pump works properly.

20..

Inspect wiring, from outputs 24 and 25 of control unit to roof heater water valve, for contact interruptions. Check if water valve works properly.

21..

Inspect wiring, from outputs 5 and 6 of control unit to switch box in right-hand roof unit, for contact interruptions.

22..

Inspect wiring, from outputs 3 and 4 of control unit to switch box in left-hand roof unit, for contact interruptions.

24..

Check if the air valve moves up and down, by pressing the SMOG button first to make it go all the way up, and next to make it return to its original position. If the valve fails to move, inspect the control motor and check if the valve can really move freely. If the valve does move up and down, check if the left-hand potentiometer in the roof unit is plugged in. Check if potentiometers are properly earthed.

25..

See 24.

48..

Inspect lead 29 of control unit and 6 of subelectronic control unit. Check if wire is intact, and if leads 1 and 20 of the subelectronic control unit are energized and leads 7, 14 and 19 are earthed. If any one of these leads is not or poorly connected, the subelectronic control unit is either not supplied with power or incorrectly addressed (see section on WABCO diagnostic controller).

49..

An inspection of the subelectronic control unit interior has revealed a failure. It is due for replacement.

50..

Inspect leads 13 and 10 of subelectronic control unit and wiring to front interior temperature sensor. Check if sensor is in working order. See annex 4 for resistances of this sensor.

51..

Inspect leads 24 and 10 of subelectronic control unit and wiring to rear interior temperature sensor. Check if sensor is in working order. See annex 4 for resistances of this sensor.

52..

Check if condenser fans and magnetic coupling are running. Pay special attention to the fans, for a defective fan keeps rotating, owing to the air pressure, although in the wrong direction. The best plan is to have an operator engage the airco and, at the same time, check if all the fans start rotating. A defective fan starts rotating later, counter to the other fans. If one or various fans fail to rotate, check if relays 208, 209, 210 and 211 are energized and activated. Check if wiring and leads from the relay to terminal 2 of the subelectronic control unit are intact. If the magnetic coupling is not engaged, inspect wiring, pressure sensors on compressor, defrosting thermostat and leads on relay 207 and on terminal 2 of subelectronic control unit.

53..

Inspect leads 23 and 10 of subelectronic control unit and wiring to water temperature sensor. Check if sensor is in working order. See annex 4 for resistances of this sensor.

55..

Subelectronic control unit is out of order and is due for replacement.

56..

Inspect leads 25 and 10 of subelectronic control unit and wiring to outlet air temperature sensor of front underfloor heater. Check if sensor is in working order. See annex 4 for resistances of this sensor.

Futurair

12

57..

Inspect wires and leads between terminals 17 and 5 of subelectronic control unit and water valve of front underfloor heaters. Check if relays 10 and 11 are set so that subelectronic control unit and water valve are interconnected.

60..

Inspect leads 12 and 10 of subelectronic control unit and wiring to outlet air temperature sensor of rear underfloor heater. Check if sensor is in working order. See annex 4 for resistances of this sensor.

61..

Inspect wires and leads between terminals 16 and 4 of subelectronic control unit and water valve of rear underfloor heaters. Check if relays 8 and 9 are set so that subelectronic control unit and water valve are interconnected.

WABCO diagnostic controller For thorough trouble-shooting the WABCO diagnostic controller can be used. It is the same cabinet as the one used for testing WABCO ABS/ASR. The test card for the Futurair system is available via BOVA. Whenever the diagnostic controller is used the front heater should be on, because, during testing of the heating unit, the preheater pump is occasionally engaged with the water valves shut. For details see enclosed diagnostic controller documentation.

Futurair

13

Maintenance and repair General Whenever subjecting a coach to maintenance or repair, check thoroughly if the required components, oil, gas and other items are available. If these are not used, the system may get badly damaged. Fill the airco only with R134a gas combined with an ester oil. When replacing components, leave seals fixed until component connection. Components are delivered with a slight excess pressure. This means that the escape of air on seal removal should be audible (but not near the hoses) If it is not, return the component for inspection. For smoother assembly of screwed joints lubrication is permitted, although only with an ester oil. On heating system repair the only coolant to be used for refills is the one prescribed by BOVA.

R134a gas

IMPORTANT NOTE A system equipped with Airco is filled with R134a gas, which replaces the formerly used R12. On no account use these two gases indiscriminately. Inside the system use only components specially adapted for R134a gas. The same applies to hoses and seals. Hoses must not be bent because one of the materials they are made of is a rigid plastic against leakage. Since R134a has a high water-absorbing capacity, it is vital for all components to remain sealed as long as possible. This is to avoid penetration of humid air, and consequent damage. Since R134a does not mix with mineral oils, the only oil type permitted is an ester oil.

Compressor The compressor is a BOCK FKX4-467 one, to be used only with R134a and an ester oil. It is delivered as standard item with 2.5 to 2.7 l of ester oil (ISO 55). The reason for the use of ester oil is that mineral oil does not mix with R134a. If a mineral oil is used all the same, it will slowly but definitely be carried along by the gas from the compressor, to accumulate somewhere in the system. In the long run the compressor will start running dry and the system get clogged. The consequence may be serious damage. When renewing ester oil, check if the new oil has been stored sealed against penetration of water. When installing a new compressor, always check, from the type plate, if it is the right one, adapted for R134a gas and ester oil. A new compressor has a run-in period of about 200 hours, during which it will exude a bit of oil from the sealing rings. Check the compressor oil level through the sight glass at the compressor rear.

Drier The drier is accommodated next to the condenser. The air flows bottom up. When mounting a new drier, mind the flow direction, which is indicated by an arrow. If this arrow is absent, install the drier long side up. Replace the drier whenever opening the system, or else at least once every year.

Futurair

14

Operational mode The control unit is equipped for airco testing, which is called the operational mode. On coach delivery this test has already been performed by BOVA. Check if the airco works to perfection by verifying the data against the curves in the graph in annex 3. These data are: # high compressor pressure # low compressor pressure # outside air temperature # outlet air temperature in roof channel. Pre-test conditions: # Make sure that the coach has been shaded against the sunlight for quite some time in advance. # Open all the air nozzles. # Shut doors, windows and roof shutters. # Make sure there is no one in the coach. # Ensure that the outside air temperature is 18NC or more. # Equip the compressor with one gauge to the high-pressure end and one to the lowpressure end. # Read the outside air temperature from the control unit. Start the coach. Set operational mode by pressing buttons 4, 5 and 9 (-, + and AC) simultaneously and turning the switch from 1 (off) to 0 (automatical mode). The outlet air temperature appears on the display. Keep the buttons pressed until the display starts flashing. Let the motor run at 1250 rpm (DAF and MAN) or 1200 rpm (Mercedes), which equals a compressor rate of 1500 rpm. Allow the system to stabilize at this speed (this takes a few minutes). Read high and low pressures and outlet air temperature (with speed unchanged) and note these values plus the outside air temperature on the operational form shown in annex 2. Verify the data against the curves on the graph in annex 3 (Attention! The pressures measured are relative pressures. The pressures in the graph are absolute pressures).

Relative pressure (bar) 10

Absolute pressure (bar) 11

Overpressure

Underpressure -1

0

Atmospheric pressure

1 0

Absolute zero point

Futurair

15

PWM motors PWM (Pulse Wide Modulation) means that the motors are driven at infinitely variable speeds, via pulses. The PWM signal may vary between 0 and 60%, which corresponds with a speed from 0 to 100%.

24V 0V Sensors For control and regulation the Futurair system uses # # # #

outside air temperature sensor front interior temperature sensor rear interior temperature sensor sensors for outlet air temperature in :

# # #

water temperature sensor defrosting thermostat sensors for :

#

- left-hand front underfloor heater - left-hand rear underfloor heater - right-hand rear of AVS channel

- compressor outlet pressure (max) - compressor inlet pressure (min) two potentiometers for air valve positions.

Outside air temperature sensor: The outside air temperature sensor is accommodated behind the left-hand head lamp corner. It is vital for interior coach temperature adjustment. Besides, it warns the driver against road surface freezing ('slippery road'), although only once. Whenever the temperature drops below 3NC, a signal is produced and the outside air temperature shown on the display. On contact disengagement followed by re-engagement the warning against frost reappears. Whenever the sensor fails, a default value is assumed according to the temperature selector position. With the selector turned to its leftmost position, this value is +30NC, and to its rightmost position it is -10NC. The display shows the default value with 'NC' flashing. Interior temperature sensors: The two interior temperature sensors measure and adjust the temperatures in the front and the rear of the coach. Whenever either fails, the temperature measured by the other is taken as default value. If both should fail, a default value is taken and displayed with the 'NC' flashing. Outlet air temperature sensors: The three outlet air temperature sensors measure the outlet temperatures of the fans. One is accommodated to the right-hand rear of the AVS channel, to measure the roof fan temperatures. The two other ones are accommodated in the two left-hand underfloor heaters, to measure the temperatures of the front and rear heating system circuits. If any of the sensors fails, the temperature recorded last is taken as default value. Water temperature sensor: The water temperature sensor is accommodated in the cooling water system right ahead of the preheater. Whenever it fails, 70NC is taken as default value.

Futurair

16

Defrosting thermostat: The defrosting thermostat is an additional safety unit against system damage. It is accommodated in the left-hand roof unit, to measure the combiblock temperature. The moment the combiblock temperature reaches 1N, the thermostat, and consequently the magnetic coupling, are disengaged. At 4.5NC the thermostat is re-engaged. Under normal conditions this situation must be excluded, for the roof fan exhaust temperature is kept higher than 4NC. Pressure sensors: The pressure sensors on the compressor measure the pressures to the compression (outlet) end and the suction (inlet) end, to protect the system. The moment the outlet end pressure exceeds 22 bar (absolute value), the magnetic coupling is disengaged. This situation may occur when the system is clogged up. The moment the inlet end pressure drops below 1.35 bar (absolute value), the magnetic coupling is disengaged. This situation may occur in the event of system leakages. Potentiometers: The potentiometers are integrated in the valve motors, to check if the required air valve positions agree with the setpoints.

Water valves The Futurair system uses three water valves, two for the underfloor heaters and one for the roof heater. They consist of a DC-motor, actuated by the electronic control unit, and a valve. Emergency control: If any DC-motor breaks down, the valve can be opened or shut with a screwdriver, but only after detachment of the motor from the valve.

Roof unit The roof unit accommodates components for airco, heating and ventilation. It is accessible via the roof. The two service traps are opened via two fasteners. The valves bear rods to keep them open. When shutting them, make sure that the water baffles fit in their proper places. The best plan is to pull them out and shut the valve. After shutting check if the water baffle covers the coach roof all over its length. The roof units also accommodate the heating system vent nipples.

Water baffle The water baffle holds back the water from the roof and serves as coarse prefilter. Check it at least once a month and clean it, if required. Remove it by unscrewing the four nuts.

Dust filter or cara filter This filter is accommodated in the roof unit. Check it at least once a month, and clean it, if required. Remove it by unscrewing the two screws in the roof unit.

Relays and fuses Annex 1 presents a complete circuit diagram for heating, ventilation and airco. See wiring diagram on page 6 for positions of fuses, relays and plugs.

Futurair

17

Order numbers Electric components Control unit for system with airco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219592 Control unit for system without airco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219593 Subelectronic control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219594 Buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B190179 Water valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219107 Preheater Webasto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B207444 Preheater water pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B500091 PWM motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B511488 Air valve motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L: B511498, R: B511499 Defrosting thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B511502 Magnetic coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219595 High-pressure thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B511045 Low-pressure thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B511044 Water temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B221475 Outlet air temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219526 Interior temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219526 Outside air temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219511

Heating Front heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B193759 Underfloor heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219512 Roof unit combiblock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L: B511494, R: B511495 Heating block (if airco is absent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L: B511496, R: B511497 Webasto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B207444 Preheater pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B500091

Airco Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219520 Roof unit combiblock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L: B511494, R: B511495 Expansion valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B511491 Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219510 Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219518 Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B219523

Futurair

18

Annex 1: Complete circuit diagram The plugs are numberd by a character and a number. The character indicates the lokation of the plug in the coach. These lokations are: A: B: C: D: E: F: G: H: J: K: L: M: N: P: R:

Located behind the middle dashboard sector in front of the coach. Mainloom, left in the front fusebox. Below the dashboard for the direction indicator switch. In the middle of the coach in the sleepingcompartment. This fuse/relay panel exists out of 2 panels. The toppart is used for the electronics of ABS, ASR, AVS and integrated retarder. In the connectorbox above the engine. On the panel above the batteries. In the AVS channel, right and left in front of roofunits. In the AVS channel, right and left behind the roofunits. In the interior light covers near the digital clock. Near the preheater. Near the airconditioning condensor In the luggagecompartment In the luggage compartment, behind the toilet. Extra luggagecompartment (rear right) Serveral in gearbox compartment

Z: R:

Fuses on panel B, D, F, N. Relays on panel B, D, F, N.

Fuses and relays 000 upto 199: panel B. Fuses and relays 200 upto 259: panel D. Fuses and relays 260 upto 299: panel N. Fuses and relays 300 upto 399: panel F. RD WT BN GN GS GL OE ZT BW PS RE

Futurair

= Red = White = Brown = Green = Grey = Yellow = Orange = Black = Bleu = Purpel = Pink

19

Wiring survey

Futurair

20

Futurair

21

Futurair

22

Futurair

23

Annex 2: Operational form Coach number

................

Motor brand

................

Motor speed

................ rpm

Date

................

Form filled in by

........................................................

measured value

addition

reference value for graph

inlet pressure

..........

1

.......... bar abs.

outlet pressure

..........

1

.......... bar abs.

outside air temp.

.......... NC

exhaust temp.

.......... NC

front interior temp.

.......... NC

rear interior temp.

.......... NC

Futurair

24

Annex 3: Operational graph

Futurair

25

Annex 4: Temperature sensor resistances Temperature in NC -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150

Resistance in Kohm 328,40 237,70 173,90 128,50 95,890 72,230 54,890 42,070 32,510 25,310 19,860 15,690 12,490 10,000 8,0600 6,5360 5,3310 4,3730 3,6060 2,9890 2,4900 2,0850 1,7530 1,4810 1,2560 1,0700 0,9155 0,7861 0,6775 0,5860 0,5086 0,4429 0,3870 0,3392 0,2982 0,2629 0,2324 0,2061 0,1832

Resistance tolerance limit: 3%

Futurair

26