SPR 2018

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Page 17 of 38

A W C c N E W S Y O U N E E D , T H E P R O D U C T S Y O U W A N T WAS IT THE CLEANING METHOD? Craig, who is also a RSES Houston Chapter board member, also noticed some service techs' standard rinsing techniques were bending fins on curved and inaccessible coils. On rooftops where two coils were close together, ser- vice techs didn't use small hand spray- ers, but continued to use trigger spray nozzles, even though they couldn't ac- cess the coils with a straight-in stream. Afterward, they used fin combs that tore and weakened the serrated fin designs. On coils near cooking grease exhaust stacks, Craig also found technicians not rinsing caustic cleaners thoroughly within the manufacturer's prescribed six-minute limit. Besides fin deteriora- tion, residual chemicals on inadequately rinsed coils can also corrode the bond between coil and fin that's critical to ef- ficient heat transfer. "One technician would apply the chemical on one unit, then apply it to other units on the roof," said Craig. "By the time they got back to the original unit, 15-30 minutes had passed." WAS IT THE WATER SOFTENER? Craig suspected salt water was also inad- vertently adding deterioration, because service techs hadn't tested the alkalinity of rooftop hot water spigots used for coil rinsing. "Water's natural alkalinity can also corrode a coil," added Craig. The chain's hot water supply is high in salt content due to water softeners commonly used in the restaurant indus- try to facilitate sparkling. Thus, the coils were continually exposed to salt water even though they weren't near coastal areas. THE VERDICT The problem was diagnosed as using caustic coil cleaners, but not properly rinsing within the prescribed six-minute duration after application. Further- more, the coils were being cleaned too frequently, most likely due to grease build-ups from nearby rooftop grease exhaust hoods. Ironically, the restaurant chain was proactively protecting its equipment in- vestments with preventive maintenance, but improper cleaning techniques defeated the purpose. While some technicians had forgotten the proper techniques and chemical choices, oth- ers were executing proper applications based on their previous training, which explained the randomness of affected units. Therefore, Craig designed a coil cleaning training program to prevent future fin and other RTU damage. The seminars were executed in two-hour classes for groups of 10-15 technicians in Insco's suburban Houston branch in Stafford, Texas, which is designed for hands-on training. Illustrating its regained confidence in Insco, the chain recently bought nine more units of the same RTU brand. "This is the type of service all distribu- tors should extend to their service tech clients," said McGaughey. The lesson learned is coil cleaning chemicals are invaluable when used properly. When used improperly or with the wrong techniques, expensive RTU equipment can be ruined. Therefore, service contractors should periodically review their crews' cleaning methods. Distributors and their chemical manu- facturer suppliers should be available to offer technical support or to tackle tough cleaning situations. Jerry Myren is western region sales manager for RectorSeal Corp. A ir C onditionin g HVA C p l um b in g pumps P i p in g Water Heaters Building Automation g g Water Filtration Testin g & Filtration Bo i le r s Hydronic Products Refrigeration V enting /L ouvers /D amper s F an s Clima Heating Products Hangers & S up p Temperature Controls W at e r T r e atm e n t co m fo r t SINKS Pl um b ing F ixture s p ort s NEWS YOU NEED, THE PRODUCTS YOU WANT Learn more about the featured products in this issue at HVACPproducts.com/ market. HVACPproducts.com/subscribe

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