Preventive Maintenance for Vertical Ptac Units

Today, the benefits of a well-organized maintenance program are two-fold. Facilities managers and building owners can realize substantial savings on conditioned air equipment repairs when a systematic schedule for routine checkups and minor repairs is started.

Budgeting for planned mechanical system repairs is always preferred over waiting for a catastrophic event to occur and then draining the “emergency fund” budget to pay for it. Life use of the equipment is extended when periodic inspections of the mechanical systems identify and address small problems, increasing the property value and providing a better return on the initial investment.

The second benefit has to do with indoor air quality. Poorly maintained mechanical systems are a breeding ground for airborne contaminants. Providing regularly scheduled maintenance on the mechanical systems will reduce objectionable odors, and discourage the formation of algae, mold, and bacterial growth. A clean building is a healthy building.

This article details the procedure for a preventive maintenance program for vertical packaged terminal air conditioners (ptac’s).

Scheduled preventive maintenance inspections (PMIs) should be performed four times a year. At the beginning of the cooling season, a complete mechanical cooling check should be performed.

Periodic minor inspections may be necessary during the cooling season to adjust for variations in climate. At the beginning of the heating season, a complete mechanical heating check should be performed. Again, periodic minor inspections may be necessary to adjust for climatic changes.

Cooling Season

Note: Disconnect the power!

  • Remove access panels and perform a visual check of the equipment. Look for obvious changes in the unit such as broken belts, damaged coils, and/or evidence of extended wear on any moving part.
  • Are there any unusual odors? This could indicate burned motor windings. Are there any leaks (water, refrigerant)? Is the drain pan clean?

    Ask the tenant, homeowner, or user if they have noticed anything unusual with the equipment, such as unusual sounds.

  • Inspect all electrical connections. Look for frayed wires and poor connections. Terminal ends that are loose will eventually fail, causing a loss of performance or worse.
  • Check fan motors and blower assemblies. Some units may require a drop of light oil to motors and/or bearing assemblies (look for oil cups). Check setscrews and motor mounting hardware; make sure these are tight. Centrifugal fan blades and blower cage assemblies must be clean to operate efficiently. Brush and/or vacuum as necessary.
  • Inspect both indoor and outdoor coils; use a fin comb to straighten out any damaged fins. These coils must be clean for proper operation. Do not use a solvent-based cleaner for this. Some solvents produce a noxious odor when you start the fan or electric heat. Nothing clears a building out faster than an overpowering chemical smell.
  • Also, look for oil leaks or stains on or around the coil and refrigerant lines. The presence of oil here indicates a potentially serious problem (refrigerant leak).

  • Inspect the drain pan and drain line (if any); clean. A good idea here is to use an antifungicide tablet to keep the condensate system free from bacterial contaminants.
  • Check the pitch of the unit. Over time, the building and equipment may settle, causing a shift in the direction the condensate flows. Ideally, the unit should pitch downwards from front to back to allow for proper drainage.
  • At this time, check the seal around the unit. Air leaks may make the conditioned area uncomfortably drafty or produce noises. Visually inspect the foam gasket between the wall and the unit; especially take note of the separation between the air inlet for the condenser and the condenser coil discharge. These two areas must be sealed off from each other.

    If you experience poor cooling operation or erratic operation, check for air recirculation at the condenser coil.

    Coy is the technical service manager for Enviromaster International LLC (EMI), Rome, NY, (website).

    Publication date: 06/11/2001

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