Impulse L4-2254cc 2.3L SOHC (1988)
Refrigerant: Service and Repair
2. Evacuating
Evacuating
Specification for system pump-down used here is 28 - 29.5 inches vacuum. This reading can be attained at or near sea level only. For each 1000 feet of
altitude, vacuum reading will be 1 inch lower. For example, at 5000 feet, only 23 - 24.5 inches of vacuum can be obtained. The system must be
completely discharged before evacuation. Damage to vacuum pump may result if pressurized refrigerant is allowed to enter.
1.
With gauges connected, remove cap from vacuum hose connector. Install gauge manifold center hose to vacuum pump connector. Open low side
gauge manifold valve only.
2.
Ensure low side gauge is calibrated correctly. It should be reading zero. If not, adjust calibration.
3.
Evacuate system until low pressure gauge reads at least 28 inches of vacuum. Continue evacuating system for an additional 15 minutes for routine
system servicing. If any parts have been replaced, evacuate for 20 to 30 minutes.
4.
When system evacuation is complete, close low side gauge manifold hand valve and turn vacuum pump off.
5.
Check ability of system to hold vacuum. Watch low side gauge to see that it does not rise faster than 1 inch vacuum every 4 to 5 minutes. if low
side gauge rises too rapidly, install partial charge and leak test. Evacuate system again.
6.
If system holds vacuum, charge system with refrigerant.
Exercise System
To remain in good operating condition, A/C systems must be used periodically. Manufacturers recommend that when the air conditioner is not used
regularly (during winter, for example), it should be operated for a few minutes every two or three weeks.
Checking out the system for the effects of disuse before the onset of summer is one of the most important aspects of A/C system servicing.
Clean condenser core of obstructions such as leaves, bugs and dirt. Blockages reduce heat transfer and impair system efficiency. Make sure the space
between condenser and radiator is free of foreign matter.
Make certain evaporator water drain is open. Certain systems have an evaporator the engine compartment and one in the trunk.
Flush System
It is not necessarily mandatory to flush an A/C system if a component has been replaced due to failure. Due to refrigerant recovery requirements,
products previously used for flushing cannot be utilized. Under no circumstances should CFC's or methylchloroform be used for flushing.
An alternative to flushing is installation of an in-line filter ahead of expansion valve or orifice tube. Filters for this purpose will efficiently trap particles
that may clog components and are large enough to provide long service life.
