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Floyd Hall Arena will now be closed for three to four weeks to melt the underfloor space and hopefully reduce or eliminate the heave and inspect the concrete slab for damage.


In August, the ice resurfacer door is almost level with the concrete.


In January, the ice arena slab is almost seven inches higher than the surrounding concrete.


Floyd Hall Arena will now be closed for three to four weeks


to melt the underfloor space and hopefully reduce or eliminate the heave and inspect the concrete slab for damage. Te heave is concentrated within 30 feet of the ice resurfacer door and has created a shelf that could potentially crack off at any time. Once the ice is removed, that end of the rink will be weighed down to help expedite and concentrate the melting. Time will tell us the severity of the damage.


So how could this have happened so quickly, you might ask?


Te fact is the severity of the heave could probably have been prevented with better maintenance of our subfloor heating system and if the expansion joint on the rink had not been compromised. A series of events, some within the rink’s control and some not, brought about this significant repair and will result in a loss of business. Te primary cause, the leak in the heat exchanger, could probably not have been prevented. At 18 years old, the heat exchanger was close to end of life but possibly not quite there yet. We could have monitored the components of the heat exchanger better, especially the calcium chloride solution that was being pumped through the system.


A subfloor heating loop has several components: the heat


exchanger, the heat transfer fluid, the pipes and headers that prove a conduit for the fluid to move around, and the pumps and motors that provide the power and energy to move the fluid. Each of these items must be closely monitored, maintained and replaced as necessary to prevent expensive repairs down the road.


Steps to Avoid Catastrophe


In order to reduce the possibility of a failure in the underfloor heat system, several steps can be taken. First and possibly most importantly, the heat transfer fluid must be tested annually and periodically flushed to insure health of the system; levels should be monitored as well.


All heat transfer fluids must be tested for clarity, specific


gravity, freeze point, level of corrosion inhibitor and metal content. A healthy heat transfer fluid for a subfloor heating system will have a consistent color, proper specific gravity, a freeze point between zero and plus 10 F, correct level of


12 SUMMER 2 017


corrosion protection and no metal content. A subpar heat transfer fluid will be cloudy, even brown, with a freeze point too high or low and potentially contain high metal content.


Most underfloor systems are equipped with an expansion


tank. Expansion tanks hold reserve fluid in case of a leak, provide a vehicle for air to exit the system, and allow for a place for fluid to reside as the heat transfer fluid expands and contracts with temperature change. Levels must be maintained so that no air is allowed into the system, as air in any refrigeration system inhibits efficiency and presents a catalyst for corrosion. A properly functioning system will maintain a consistent level and any significant change in level may indicate a leak in the system or other issues.


Corrosion inhibitor should be added in quantities specified


after a test by a certified lab or refrigeration contractor and changed according to manufacturer recommendations. Calcium chloride and glycol should be checked periodically with a handheld refrigerant leak detector. Tese fluids can absorb ammonia or Freon. Indication of ammonia or Freon in these fluids can indicate a leak in an underfloor heat exchanger. Heat transfer fluids should be filtered, and filters should be changed regularly to keep out debris and contaminants.


Any corrosion or leaks in exposed pipe must be addressed


immediately. Both calcium chloride and brine can be corrosive. Leaks must be addressed because brine and glycol are not supposed to be released down drains, into ground water or into the soil. Brine and glycol are dangerous and can kill if consumed by animals or humans. Corroded pipes may need to be repaired or replaced but at a minimum must be scraped, primed and painted.


Pumps and motors should be inspected semi-annually


and greased and maintained according to manufacturers’ specifications. Motor couplings should be replaced regularly to prevent premature failure. Motors should be checked for shorts and voltage/amperage changes.


Te plan for monitoring and maintaining the subfloor heat system should include the following:


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