Operating instructions
IM 950-1 / Page 32 of 38
10. Clean any rust spots with steel wool and paint with 
  rust inhibiting paint.
11. Clean insulation or replace if necessary.
12. Check insulation on refrigeration piping and 
  replace if necessary.
13. Check all fasteners and tighten as required.
14. Clean and oil damper door and linkage.
15. Test run chassis before reinstalling.
Equipment Protection From The
Environment
The metal parts of this unit may be subject to rust or 
deterioration in adverse environmental conditions. 
This oxidation could shorten the equipment’s useful 
life. Salt spray, fog or mist in seacoast areas, sulphur 
or chlorine from lawn watering systems, and various 
chemical contaminants from industries such as paper 
mills and petroleum reneries are especially corrosive.
If the unit is to be installed in an area where 
contaminants are likely to be a problem, special 
attention should be given to the equipment location 
and exposure.
1 
  Avoid having lawn sprinkler heads spray directly 
in or on the outdoor louver.
2 
  In coastal areas, the units must have the corrosion 
protection package to maintain the warranty 
coverage.
Regular maintenance will reduce the buildup of 
contaminants and help to protect the outdoor 
section of the unit.
1 
  Frequent washing of the outdoor section,   
  condenser fan blade and condenser coil with 
  fresh water will remove most of the salt or other 
  contaminants that build up in the outdoor section 
  of the unit
2  Regular cleaning of the cabinet with a good non- 
  abrasive polish will provide protection and keep it 
  in good condition.
3  A mild liquid cleaner may be used several times a 
year to remove matter that will not wash off with 
water.
The best protection is frequent cleaning, 
maintenance and minimal exposure to contaminant.
Maintenance (Scheduled)
Incremental conditioners are built to last. With 
proper care, the unit should provide uninterrupted 
service for many years. Scheduled maintenance of 
this equipment as described below, is the key to the 
equipment’s longevity.
A.
  Air lters must be cleaned at regular intervals. 
  Twice annually may be adequate in some areas 
  while twice monthly may be required in others. 
  Areas with high dirt and lint content or heavy 
  usage of units require more frequent lter   
  maintenance than those areas of relatively clean 
  operating or low usage conditions. Unit   
  malfunction will occur if air lters are not kept 
  clean. Rinse lter with hot water and a mild  
  detergent.
B.  McQuay recommends that every year the chassis 
  be removed for a thorough checkup. This should 
  be completed as follows:
1.  Unplug unit from power source.
2.  Remove front panel.
3.  Remove chassis from cabinet and move it to the 
  maintenance department. Replace with spare 
  chassis or weather plate.
4.  Check all seals and insulation and repair as 
  required.
5.  Check all wiring and controls for hazardous  
  conditions.
6.  Thoroughly clean discharge grilles.
7.  Cover motors and control module with water tight 
  material and wash evaporator coil, condenser coil 
  and base pan using hot water and a mild soap.
CAUTION
Residential and institutional cleaning compounds can 
cause permanent damage to the packaged terminal 
unit. To avoid damage to unit controls and heat transfer 
surfaces, do not spray cleaning compounds onto the 
discharge grille, return air opening, or unit controls. 
Normal cleaning can be accomplished by wiping the 
unit surface with a damp cloth. When using cleaning 
compounds on carpets, oors or walls, turn the unit off 
to avoid drawing potentially damaging vapors into the 
package terminal unit.
8.  Check condensate removal system and assure 
  proper operation. Pour at least two (2) cups of 
  water into evaporator drain pan and verify proper 
  operation. Clean condensate drain and clear weep 
  holes located at the bottom rear of wall sleeve.
9.  Dry equipment thoroughly, especially electric 
  parts and installation. 










