ICING OF COOLING COMPRESSOR REFRIGERANT LINES

and/or AIR HANDLER DURING SUMMER OPERATION

Below are photos of problems that can be found with cooling compressors and heat pump systems during a home inspection.

There are may reasons that a cooling system develops ice on the refrigerant lines and air handler cabinet.   One of the most common reasons is a dirty evaporator coil (inside the air handler) or dirty filter.    When the refrigerant lines are cooling the inside coil and the flow or volume of air passing through the coil is too low the metal tubing and surrounding coil vanes will "over cool" and freeze the liquid condensate that normally drips off the cooling coil to the drain pan.    If the cycle is not interrupted an ice block around the refrigerant lines or the inside cooling coil cabinet will likely result.

An ice block forms on the low pressure refrigerant line at the compressor on a very hot day.

AIR HANDLER, front side view:   This is the largest ice block I have ever encountered with a cooling system.   The air supply vents in the dwelling had no air flow.

AIR HANDLER, rear side view:   The ice block is at an angle because the coil inside the cabinet is installed at an angle.   The ice typically forms first at the copper tubing on the outer edges of the coil.

AIR HANDLER, rear/bottom side view:

In this photo the refrigerant low pressure line has formed ice inside the exterior wall.   The air handler in this dwelling was located in the attic and the refrigerant lines were routed across the ceiling and down 2 floors through the exterior wall.

The oval shape on the second floor exterior wall is a "cold bubble" that formed on the interior wall board due to ice forming inside the exterior wall.   The refrigerant lines are routed through the exterior wall from the attic to the ground.  The center oval was very cold to the touch due to ice inside the wall.  

This is a typical "A" -type inside coil that is very dirty.

This is a typical "Slanted" coil, extremely dirty, often found inside vertically mounted air handlers installed in closets or inside the dwelling.    The wire running horizontally across the coil is to be use to hold the filter in place against the coil surface.    A filter was not installed at the time of the inspection.

OTHER PROBLEMS WITH COMPRESSORS

Icing of this nature occurs on the exterior surfaces of heat pump compressors during the winter months only.     The compressor fan induces moist air flow through the exterior coils during sub-freezing external temperatures and discharges through the top fan grill.    This ice will be removed during a defrost cycle of the external coils scheduled every 30-90 minutes.

The pad under the compressor has settled due to uneven soil settling at the rear wall of the dwelling.   This can cause a shortened service life due to inadequate lubrication of the compressor's bearings.

The homeowner built the deck over the compressor.   Unfortunately, the exhaust fan discharges through the top of the unit.   The decking inhibits the full and free flow of exhaust air flow across the exterior coil.    Modifications to the decking was recommended.

Leaves that have stacked along the sides of the compressor inhibit the free flow of air through the external coils   At the very least, this will reduce the efficiency of the cooling or heating coil system.

CONDENSATE LINES