ACCA Now September/October 2020

Ad Index

T E C H C H A L L E N G E

Arkema. Tip-in Flyer www.forane.com Carrier Corporation . 9 www.carrier.com/nextgen Daikin North America LLC. 2 (Inside Front Cover) www.daikincomfort.com Cinch Home Services. 23 www.cinchhomeservices.com/join-network Emerson. 11 www.climate.emerson.com/livability Federated Insurance. 15 www.federatedinsurance.com Fujitsu. 13 www.fujitsugeneral.com Goodman . 35 (Inside Back Cover) www.goodmanmfg.com Honeywell. 27 www. fluorineproducts-honeywell.com/ refrigerants/SolsticeN41 Jackson Systems . 21 www.jacksonsystems.com/filter-fetch MiTek Wrightsoft Corporation. 31 www.wrightsoft.com Mitsubishi. 27 www.NextGenVRF..com Nortek. 33 www.nortekhvac.com Nexstar Network. 22 www.nexstarnetwork.com Pearl Certification. 36 (Back Cover) www.pearlcertification.com/ACCA Qtech® . 20 www.acca.org/qtech Rheem. 17 www.rheem.com/EcoNetSmartThermostat Schedule Engine. 24 www.scheduleengine.com XOi Technologies. 25 www.xoi.io York. 29 www.YorkHVACDealer.com

B Y D I C K S H AW

Share this challenge with your entire staff and see who can figure out the diagnosis first.

A medium temperature cooler utilizing R-134a with a TXV metering device has a customer complaint of warm beer. The symptoms at the convenience store confirm inadequate cooling and the compressor appears to be short cycling on the high or low pressure control. What are the “possible causes” (Note: There is only one problem intended) with the following measured/ calculated conditions on this field service check sheet?

FIELD SERVICE CHECK SHEET Compressor Discharge Temp. Condensing Press./Temp. Condensing Outlet Temp. Condenser Sub cooling Entering Feed Device Temp. Evaporator Press./Temp. Evaporator Outlet Temp. Evaporator Superheat Compressor Inlet Temp. Condenser Split

180 deg. F.

105 psig / 90 deg. F.

78 deg. F. 12 deg. F. 15deg. F. 42 deg. F. 37 deg. F. 40 deg. F. 68 deg. F. 71 Deg. F. 75 deg. F. 52 deg. F.

5 psig / -3 deg. F.

Total S. H.

Ambient Temp. Room/Box Temp. Compressor Volts

240 V.

Compressor Amp. Draw

Low

Looking for the Answer? Check www.accanowmagazine.com on October 31, 2020, for the answer to this issue’s Tech Challenge.

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SEPTEMBER/OCTOBER 2020