Tackling Condensate Leaks

While condensate is a natural byproduct of the air conditioning process, it can be a source of annoyance for the average business owner or facilities manager. Condensate leaks are a common source of trouble for many commercial air conditioning systems. For the average roof-mounted system, an ongoing leak presents a hazard not just to your equipment, but also to customers and merchandise.

The following goes in-depth about the most common problems that cause condensate leaks in commercial HVAC units.

Clogged Condensate Drains

Blocked condensate drains are the most common source of leaks. Under normal circumstances, the HVAC system's various drainage components remove excess condensate that forms during the unit's operation. However, dirt, debris and other airborne material can collect within the drainage pipes, provoking mold and algae growth that further plugs the pipes shut.

In most cases, all it takes is a blast of pressurized air or nitrogen to dislodge the cumulative blockage and restore normal condensate drain operation. The drain pan should also be thoroughly cleaned of any dirt, debris and/or algae buildup.

The use of an algaecide on areas where algae and mold buildup occur can help prevent future problems. You should also add a couple of chemical tabs to the drain pan to block further algae growth.

Evaporator Coil Icing

It's not uncommon to see small amounts of frost on the evaporator coil during A/C operation, especially under relatively cool conditions. If the coil's operating temperature dips below 32 degrees Fahrenheit, however, it can cause the condensate to freeze into sheets of ice, blocking heat transfer and eventually causing the HVAC unit to shut down.

The icing issue is usually caused by the following:

  • Low refrigerant pressure – Often the result of a low or restricted refrigerant charge, as well as low ambient temperatures.
  • Air flow restrictions – Any blockages in air flow, whether caused by a dirty air filter or a defective blower fan motor, can cause the condensing coil to ice over.

In most cases, the unit itself will shut down and transition to "defrost" mode until all of the ice has been cleared. If your unit lacks one, you'll want to shut it down manually and allow it to defrost in that manner. You may also want to check refrigerant levels and pressures, just in case.  

To prevent freeze-ups in the future, consider installing low-ambient controls that allow the unit to operate at lower temperatures.

Improper Pitch

Your air conditioning system was designed to lay flat and level. In many cases, however, the unit may be pitched accidentally at the same angle as the roof it sits on. This can cause condensate to run away from designated drains and onto the roof and other areas. During a visual inspection of the HVAC system, use a bubble level to make sure the unit sits perfectly flat and level.

Although your HVAC unit isn't designed to sit on a pitch, your unit's condensate pipe is another story. Simply following the recommended condensate pipe pitch guidelines can help prevent flooding from occurring.

Condensate Carry-Over

Carry-over occurs when high-velocity winds carry condensate away from drainage areas and onto the surrounding environment outside of the unit. The underlying cause is usually a system that's improperly pitched, exposing the evaporator coil to high outdoor winds. Most HVAC systems can't function properly when exposed to wind speeds in excess of 450 to 500 feet per minute.

The key is to make sure the unit sits flat and level, so the evaporator coil is less likely to be exposed to high-velocity winds.

These and other preventative steps can help you keep your commercial HVAC system operating at peak efficiency and your customers happy. Contact a professional for commercial air conditioning installation and repair.

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