There is oil in a compressor and if the unit is not level, then the oil may not get to all the areas that it should. Once in a while, this may cause a premature failure of the unit, bearings to wear out more quickly and some inefficiency in cooling. Seldom does this cause damage to the unit.
“Walk off pad” or shift
Also, if the condenser is not level, it may start to shift off or “walk” away or off of the pad, thus putting stress on the refrigerant lines, electrical conduits, etc. Generally, if the unit is only slightly or moderately un-level this does not present a problem.
Most manufacturer installation instructions recommend that the unit be level and secured to the pad or platform upon which it sits.
Units are often out of level to some extent. Should they be significantly out level, damage may occur. Leveling a unit is relatively easy, but should be done by a professional to avoid damaging the refrigerant line or the electrical connection.
Who to consult or have fix it:
HVAC contractors are the ones who are most qualified to do this type of work. Sometimes referred to as Heating and A/C contractors.Who to consult? Air-conditioning technician.
Generally a HVAC contractor / air-conditioning technician will level a unit quickly and easily. At times a handy man may assist with the leveling process.