Here Comes Judge Powell
That’s right, just call me the Sultan of Superheat.
Actually, for the second year in a row I was asked to be one of the judges among a number of eminently more qualified people.
However, thanks to Jim Knutson, Scotsman’s regional service manager for the Central US (who helped dust off my musty brain over what I once remembered from hvacr classes about determining superheat) I took my spot near one of two ice machines on the floor of Bartle Hall in downtown Kansas City.
Throughout the huge convention center, some 4,000 mostly young people were competing in 70 skill areas. About 50 or so were dealing with hvacr, where 10 stations were set up.
The ice machine servicing area focused on garnering proper nameplate information and then determining superheat.
The nameplate drill was to encourage technicians to put down as much information in writing about a machine as possible. This helps in service work, especially if you need to place a call to a supply house, manufacturer’s rep, or the manufacturer itself. Taking a written record from the jobsite aids in future work should the nameplate become damaged and the information marred.
The superheat aspects required the technicians to remember the formula for calculating superheat. A manifold gauge was already hooked up to each ice machine. The tech had to remember which of the gauge readings to use in superheat measurement. Probes were hooked up for measuring suction and discharge temperatures. By using a digital thermometer, techs were able to see both readings — and hopefully know which one was used in superheat calculations.
Some started out using the wrong psi or temperature, but knew that the resulting superheat reading was wrong. The fact that they knew that immediately and reworked the formula in another way until they arrived at a more realistic number was a good sign. It is better to take one’s time coming up with the correct number, than to do any adjusting based on wrong information.
Some techs drew a blank on the superheat formula. But drawing a blank can happen on a jobsite, even when no one is looking over one’s shoulder.
Why not write out the methods for determining superheat and keeping it in your wallet or in the truck. There is no rule against crib sheets in the real world.
Powell is refrigeration editor. He can be reached at 847-622-7260; 847-622-7266 (fax); or PowellBNP@aol.com (e-mail).
Publication date: 09/03/2001