How to Teach Commercial HVAC without a Commercial Lab HVACR & Mechanical Conference for Education Professionals March 11 – 13, 2013 Colorado Springs, CO Don Crawshaw Pikes Peak Community College HVAC Department Chairman/instructor My Background I taught Basic Electricity and Advance Refrigeration at Intellitec College for 18 months Lab Area of 500 Sqft I have been at PPCC for three years now Lab Area of 1000 Sqft The real problem with teaching commercial courses is….. SPACE The other problem is no matter how much space you have.... We need more hands on training in the lab! So what do you do if you don't have the space and/or equipment? Go out into the community That takes contacts Former employers Former service accounts Advisory Committee Former Students So does that mean.... Field Trips??? How productive are field trips? So instead of just a ... Field Trip Non-hands on Troubleshooting Field Trip Refrigeration Problem Compressor B-1 not running: Refrigeration Problem Compressor B-1 not running: Amp Draw, L1 60 amps, L2 60 amps, L3 0 amps, L1 to L2 1.5 ohms, L1 to L3 infinite, L2 – L3 infinite ,L1 to Ground infinite, L2 to Ground infinite, L3 to Ground infinite Refrigeration Problem Multi-Deck Dairy BR 12 to warm: Refrigeration Problem Multi-Deck Dairy BR 12 to warm: Looking at Refrigeration Schedule it shows that the Suction Evaporator Temperature for BR 12 should be 25* (On R404a = 64#) EPR set at 105# Refrigeration Problem Compressor A1 not running: Refrigeration Problem Compressor A1 not running: Oil Pressure switch tripped on A1 No oil level in oil float of A1 Oil level at ½ glass in other compressor oil float Oil level in Turboshed is at ½ glass Refrigeration Problem Compressors B-1, B-2 and B-3 running all the time will not shut off: Refrigeration Problem Compressors B-1, B-2 and B-3 running all the time will not shut off: Refrigeration Problem Compressors B-1, B-2 and B-3 running all the time will not shut off: Refrigeration Problem Compressors B-1, B-2 and B-3 running all the time will not shut off: Pressure at Danfoss controller for Rack B shows 80# Pressure at rack transducer shows 40# Component ID Shut off refrigerate going to Systems BR-9 to BR 11: Component ID Oil Pump BR-4 and Oil Pump BR-5 Component ID Receiver A-AR Component ID System A4, System B9, System A1, System B8 Local Campus Field Trips Now you can't spend all your time in the field... Although I'm sure our students wouldn't mind. So what do we do in the classroom? They have got to understand the basics Thermodynamics Basic Refrigeration Cycle Basic Electricity Basic Heating The first day of our Advance class we start off with a test. We want to see what they remember We want to see what they forgot We want to see what we forgot to teach them If your students are like mine they just love to take test Clickers You can get honest results The students don't have to feel bad if they don't remember an answer I am not as concerned as to what the student knows as I am on what the group knows You get instant feedback Let's give it a try... What else to do in the classroom? What else to do in the classroom? What else to do in the classroom? Because we can’t do a lot of hands-on training in out lab; we do a lot of mind troubleshooting. We give them a lot of mental problems to solve. Being able to think through a problem before you arrive at the job site is very important. Refrigeration Schedule Typical Fixture Parameters What else to do in the classroom? Service Call #2: A customer reports that the low temperature reach-in cooler that had a burned compressor last week is not cooling properly. The food is beginning to thaw. The technician arrives and examines the whole system. The evaporator seems to be starving for refrigerant. When the technician approaches the condensing unit in the back of the store, he notices that the liquid line sight glass is full with no bubbles. It is located before the filter/drier. What else to do in the classroom? Service Call #3: A customer calls to indicate that the medium-temperature walk-in cooler unit that was just installed is running all the time and not cooling the box. The technician goes the job and looks it over. This is a new installation and was just started up yesterday. The hermetic compressor is sweating down the side of the housing. The evaporator fan is operating, and the box is not down to the cut-out point, so there is enough load to boil the refrigerant to a vapor. What else to do in the classroom? Service Call #1: Grocery manager calls and says that his main Grocery WI Freezer (5C) doesn’t seem cold enough; their ice cream seems too soft when they go to load the cases on the floor. What else to do in the classroom? Service Call #1: Grocery manager calls and says that his main Grocery WI Freezer (5C) doesn’t seem cold enough; their ice cream seems too soft when they go to load the cases on the floor. Strainer plugged in TXV What else to do in the classroom? Service Call #6: The grocery manager calls and says the Deli manager is complaining that his deli case (2H2) is very warm. What else to do in the classroom? Service Call #6: The grocery manager calls and says the Deli manager is complaining that his deli case (2H2) is very warm. Case refrigerant lines are on the end of the header and the rack is low on charge so this case doesn’t get enough refrigerant. What else to do in the classroom? System 2A has a suction pressure of 46# and the discharge air’s temperature is around 32*, but there seems to be low air flow in the cases, you measure 150 F.P.M., the cases are off cycle defrost and warms up 3 times a day for a round 45 minutes. What else to do in the classroom? System 2A has a suction pressure of 46# and the discharge air’s temperature is around 32*, but there seems to be low air flow in the cases, you measure 150 F.P.M., the cases are off cycle defrost and warms up 3 times a day for a round 45 minutes. Dirty Honeycomb What else to do in the classroom? System 4A which hold frozen food has a suction pressure of 10# and has hot gas defrost, which warms up once a day for 30 minutes each. What else to do in the classroom? System 4A which hold frozen food has a suction pressure of 10# and has hot gas defrost, which warms up once a day for 30 minutes each. Suction pressure set to low to make up for too long defrost. What else to do in the classroom? Local Guest Speakers What else to do in the classroom? National Guest Speakers Dave Boyd of Appion Bob Dwyer, CO Training What else to do in the classroom? National Guest Speakers Steve Coscia of Coscia Communications HVAC Customer Soft Skills HVAC Customer Soft Skills We do try to use our lab as much as we can • We don’t have a lot of commercial lab equipment • Some of the equipment was in the lab when I arrived • Some was created out of other older units • Some was bought with Perkins Funds What else to do in the Lab? Compressor Tear Down Lab (twice a year) We use Copeland’s Compressor Service DVD’s The Compressors we tear down come from local supply houses No need to take up lab space storing compressors New Problems every time A really great teaching tool We just do the best we can. There are a lot more experts here in this room Now we want to hear about the ways that you teach this to your students.