Issue link: http://read.uberflip.com/i/897697
Make Cents? The High Pressure (Discharge) reading is also directly affecting your electric usage. When the High Pressure Gauge goes up it is an indication the system is working hard and the electric usage will go right up with it. So, keeping this number where it belongs makes financial sense also! USICERINKS.COM NOVEMBER.DECEMBER.2017 / 37 reading was the temperature of the room! When the sub-floor pump was turned on manually, the thermometer reading never changed. It turns out the system was low on glycol. Once enough glycol was put into the system, the return glycol was coming back at 27 degrees Fahrenheit. The extremely fortunate part is that the glycol flowed at all. Another part of this story to understand is that the computer would not turn the pump on until the temperature was below 40 degrees. That would never happen! There is now a timer on the system to run it three hours every day and thermometers on the supply and return to make sure there is a temperature difference. BRINE/GLYCOL THERMOMETERS These two thermometers can tell the story of how well the refrigeration system is cooling the rink floor. When a system is running well, the usual differential between these thermometers is 2-3 degrees Fahrenheit. Example: 18 degrees supply, 20 degrees return; 14 degrees supply, 16 degrees return. Each building is different so the actual number will vary with each facility, and possibly at various times of year. The important number is having your ice surface temperature where you want it. When there is a change in that differential, there is some part of the system not operating correctly. The wider the differential gets, the system loses efficiency. This could be a sign of a condenser issue beginning, compressor issues beginning and/or brine/glycol issues. The most important thing is to realize there is a problem and address it before something fails. HIGH AND LOW PRESSURE GAUGES These two gauges are the pulse of your refrigeration system. This is another case where no two systems are alike and the numbers for your system will be unique to your rink. Let's say the usual pressure for your system on the Low Pressure Gauge (suction) is 30 psi, however this week we have noticed it has gone down to 25 psi. This should be a red flag that would need to be investigated. The level of primary refrigerant (Ammonia/Freon) should be checked, the freeze point of the brine/glycol checked, the flow of the brine/glycol checked, the operation of the expansion valve checked. The list can go on but the fact that there is a change requires investigating to prevent a failure. On the High Pressure Gauge (Discharge), if the normal pressure is 170 psi and this week it is reading 190 psi it is time to investigate and see what is causing this. The main culprit to high discharge pressures is usually the condenser—that would be the first stop. If not there, you need to keep investigating until you do find the issue. J Dave Wescott, CPE, CIT, is the managing partner for All Star Arenas, LLC, a rink services company out of the Tampa, Fla. area. allstararenas.com The important number is having your ice surface temperature where you want it.