Mechanical Engineer, Andy Thielen, P.E. incorporates over 30 years of experience in designing HVAC, plumbing and other mechanical systems. He provides expert consultation in the areas of root cause failure analysis, HVAC and plumbing system design, and building recommissioning for contractors and building owners. Additionally, he was the primary editor of the State of Minnesota Commercial Energy, Mechanical and Fuel Gas Building Codes used in Minnesota from 2008 to 2014.
Problem-solving is the core of what Andy does at Crane Engineering. Understanding and explaining complex technical issues to non-technical audiences is a key part of his role. One matter he worked on recently involved 246 townhome units that were flooding resulting in water damage. The allegation was that the cooling coils in the furnaces were rusting prematurely causing the condensate lines to plug and water to back up in the air conditioning units causing the flooding. Through Andy’s inspection, research into building design, maintenance practices as well as conferring with Crane Engineering’s Structural Engineers he was able to piece together what actually happened:
The condensate drains for the condominium units were stacked one above another and then connected together before the condensate lines discharged into landscaping. During discovery the Plaintiff admitted that the pipe discharge in the landscaping was prone to becoming plugged with dirt and debris. When the common piping did become plugged, the condensate backed up into the lower condominiums flooding those units.
The size and routing of the condensate piping made servicing of the piping difficult. The piping was installed in a common space between the unit walls and fell into a region of the building whose maintenance responsibility was vague amongst the property managers and unit owners. This led to a lack of service to the condensate drainage piping. Because of the arrangement of the condensate piping, air-conditioning condensate from one condominium was flooding the neighbors’ condominium.
There was a lack of consideration for the construction of the townhomes themselves involving a common phenomenon of story shrinkage. When wood framing is constructed, the wood begins to dry, and it undergoes dimensional changes that affect the actual height of the building. This can result in height changes of approximately 1/4” per floor – accumulating to 3/4” inches at the third level. When a vertical run of piping is installed in the walls of a wood framed building accommodations must be made in the design of the piping to allow the building to shrink without impacting the function of the piping. In this case, story shrinkage was not considered or accommodated, which resulted in the drain piping becoming negatively sloped.
There was a general lack of maintenance of the furnaces in each unit. This included neglecting to routinely change the air filters, which would have limited the build-up of debris on the cooling coil fins. This debris can ultimately accumulate and end up in the condensate drains, causing them to become plugged.
These four issues led to the backup of the condensate drain piping, which is shared between condominium unit owners. When the drains became plugged at one level, the condensate water backed up into other condominium units above the plug resulting in flooding and damage. None of the issues noted above were the result of the normal “rusting” of the air conditioning equipment.
Andy was able to explain what he learned about the flooding to his client and the court in a way that brought about a favorable outcome for his client.
Contact Andy with questions you may have involving HVAC, plumbing and mechanical systems.