Heating and Air Conditioning: Service and Repair

BA. Control modules







Connecting disconnecting control modules
Always switch off the ignition before connecting or disconnecting a connector or the breakout box to a control module.







Temperature
Control module must not be heated to above 80 °C. Remove control module when stoving for example.

Arc welding
Disconnect control module connectors when carrying out arc welding.

Remove a module if arc welding in its proximity.

Replacing
Do not replace a control module without checking its wiring and components. The new component may be damaged in the same way as the old one.


BB. Radio


NOTE! Make a note of the radio code before disconnecting the battery leads and the car is without voltage supply. Re-enter the code when the work has been completed.







BC. Alarm
When installing a new battery on cars with the new Guard alarm (VGLA) there is no need to disconnect the siren.


BD. Refrigerant, overview

BD1 General
Environmental legislation has increasingly emphasized the secure handling of refrigerant.

The type of refrigerant used in the A/C systems installed on Volvo cars is designated R134a.


WARNING! DO NOT USE OR MIX R134A IN AN AIR CONDITIONING (A/C) SYSTEM WHERE SOME OTHER TYPE OF REFRIGERANT IS RECOMMENDED.


To satisfy the demands of the latest legislation and permit rational handling Volvo has developed equipment for refrigerant R134a which drains, purifies and recycles the refrigerant. In addition, the unit can be used to vacuum-pump, test and recharge the air conditioning (A/C) system in the car.


NOTE! The legislation and regulations for handling refrigerant can vary from country to country. It is important that national legislation, applying to handling of refrigerants for the country where the equipment is to be used, is followed.
Read the safety precautions for handling refrigerant according to AC. Safety instructions when handling refrigerant Technician Safety Information before using the equipment!






BD2 Use of the RHS-850 and RHS-650 units
For instructions on how to use the RHS-850 unit, refer to Service Bulletin SB 8-87-803.






For instructions on how to use the RHS-650 unit, refer to Service Bulletin SB 8-87-810.



BE. General repair instructions - air conditioning (A/C) system

BE1 General
Any leakage must be repaired immediately in order to prevent moisture entering the system.

Ensure the work area is kept dry and clean. Moisture and dirt will reduce the efficiency of the air conditioning (A/C) system.

Store compressor oil in a sealed container (compressor oil absorbs water).

When working on A/C systems, for example when replacing components, open ends must always be plugged immediately after undoing pipe or hose connections. When installing new components leave the protective plugs in the holes until the component is actually needed. If dirt may have entered any component it must be inspected and cleaned.

If the car has been damaged in a collision it is important that every component in the system is inspected. Special attention should be paid to brazed joints. Cracked or deformed components must not be repaired.

BE2 Desiccant in air receiver/dryer
The dryer must be replaced when repairing a major leak or replacing a component, or if moisture is suspected to have entered the system. The unit need not be replaced more often than on every third occasion if only minor work is carried out under favorable conditions. Favorable conditions' are defined, for example, as a slow leak (over 24 hours) which is repaired immediately. When installing new components in a one-year-old car the receiver need not be replaced.


CAUTION! To avoid corrosion the system should be filled immediately after installation.


If the car is left standing for more than 24 hours without refrigerant in the system, the system must be flushed twice with about 200 grams of refrigerant. Between the two flushing operations pump the system completely empty for at least 10 minutes.


NOTE! Return used refrigerant to the supplier who is responsible for safe disposal of environmentally harmful substances.


BF. Emptying/vacuum pumping/filling with refrigerant







BF1 Draining refrigerant


NOTE! To empty the system the ambient temperature should be above 20 °C (68 °F). Running the engine a short time (five minutes) before starting work will speed up the draining process.


- Drain at the service valve.
- The A/C system will empty in approximately 25 minutes.
- Check the amount of oil (if any) that has run out when draining the refrigerant.


NOTE! There are no high/low pressure connections on the compressor. Thus is it only possible to check the operation of the low pressure switch (Pressostat). Connecting to the service valve.


BF2 Vacuum pumping


CAUTION! Check and top up with fresh compressor oil as required according to BG. Oil in the air conditioning (A/C) system below before vacuum-pumping the climate control unit on the car.


Vacuum pump system for at least 50 minutes.

BF3 Amount of refrigerant in the air conditioning (A/C) system
Check the specification label on the right side spring strut turret in engine compartment to find out the air conditioning (A/C) system refrigerant capacity.

Fill the system via the service valve (according to BG2).


NOTE! Carry out a final leak test using a leak detector on the connections where new components have been installed.


BG. Oil in the air conditioning (A/C) System

Special tools: 981 1994-4



WARNING! OIL MUST NOT BE MIXED. ALWAYS USE THE CORRECT TYPE OF COMPRESSOR OIL.


NOTE! Too much lubricating oil will impair cooling. Too little oil will cause damage to the compressor.


BG1 Topping up lubricating oil


The oil must be topped up when repairing a leak or when replacing a component. The quantity required for the component in question will depend on whether leakage has taken place slowly or quickly.

Slow leakage (longer than 24 hours)
Normally with a slow leak there is little risk of oil loss. When installing new components the following procedures apply:
- When replacing compressor: Drain and carefully measure the quantity of oil in the original condenser. Drain the oil from the new compressor and fill it with exactly the same amount of oil as drained from the original compressor (always at least 70 cubic cm (0.074 US qt.)).
- When replacing other components: Drain oil and measure quantity. Fill new component with same quantity of oil.

Rapid leakage (e.g. hose rupture)
Rapid leakage often means that lubricating oil escapes with the refrigerant.

When replacing component the oil quantities below apply to the new components:
Receiver/Drier 90 cubic cm
(0.095 US qt.)

Evaporator 50 cubic cm
(0.053 US qt.)

Compressor 200 cubic cm
(0.211 US qt.)

Condenser 20 cubic cm
(0.021 US qt.)

Hose 20 cubic cm
(0.021 US qt.)


CAUTION! When installing a complete, new system:
Check that there is oil in the compressor The other should contain no oil.


Filling the A/C system with oil


NOTE! Fill with oil before vacuum pumping.

Fig. 5 A/C System Fluid Level Inspection:

BG2 Filling with PAG oil
Procedure for topping up PAG (Poly Alkylene Glycol P/N 8708581-7) oil in car:
- Undo the unit refill valve.
- Disconnect service valve using valve needle tool. 981 1994-4.

Use filling syringe (without plastic hose) supplied with unit to top up oil. Clean syringe to avoid the possibility of mixing different types of oil.
- Measure how much oil is to be added. After topping up oil, reinstall the service valve.


NOTE! When tightening the service valve using the valve needle tool 981 1994-4 only use finger and thumb pressure, to avoid damage to the valve seal.