b'PAGE 36 / NATIONAL CLOTHESLINE / MAY, 2019W RENCH W B Y B RUCE G ROSSMANORKSCooling problems in hot weatherith summer upon us radiator in your car engine re-W yourdrycleaning moves the heat generated dur- Opening the valve wider to counteractmachinescooling ingthecombustionprocesssystem will be under greater taking place in the engine.stress. There are three methods of scale build-up will can lead to paying a lotIt doesnt matter if you are supplying water to the refrig-using a water tower, chiller or erated condenser: of extra money in solvent and energy. city water for cooling, condi- 1. Citywater.Waterfromtions that werent an issue dur- the city main is forced through B. Heat transfer efficiency. machine is working properly. tion and tripping the refrigera-ing the cooler months may be- the drycleaning machines re- Theabilityofthecondenser The following are some pos- tion high pressure safety switch.come problems as the ambient frigerationcondenserpro- coiltomoveheattothe siblescenariosfordifferent Most of the time this would(surrounding)temperature pelled by existing city water coolant.combinationofqualitative cause an error message on therises. pressure. The exiting water is Each of these factors can be data: programmerscreenandre-Mostofthecoolingprob- then sent down the drain. easily monitored using pres- 1. Inlet pressure high/out- quire a manual reset of the re-lemswillappearduringthe 2. Water tower. Water is cir- sure and temperature as indi- let pressure low: frigerationhighpressuredryingsegmentofthe culated by a pump through the cators of what is going on in A. Check for blockage inlet safety switch. This condition isdrycleaning cycle. The drying drycleaning machines refrig- the coolant system. flow path, a clogged Y strainer almost always caused by eithercycle is all about moving heat erationcondenser,overan A pressure gage and ther- betweenthepumpandthe a clogged Y strainer (see theenergy. evaporativecoolingmedia mometer at the inlet and outlet drycleaning machine. machine inlet strainer on the il-The media which moves all (looks like corrugated plastic of the coolant system located B. Heavy scale build uplustration) or excessive scalingthis heat is called a refrigerant, cubes)whichhasairforced near the drycleaning machine a build-up of scale inside the insidetherefrigerationcon-referred to generically as freon, though it to aid in evaporation arevitalformonitoringthe piping of the drycleaning ma- denser.as well as some form of coolant and into a sump where the suc- cooling system performance. chine. Onmostdrycleaningma-(generallywaterorawater tion inlet of the pump is con- Lets have a look at what the 2. Inlet and outlet pressure chinesthereisarefrigerationand glycol mixture). nected. pressure gage can tell us about rapidly changing. head pressure control valve thatItdoesntmatterwhich The evaporation of the wa- theconditionofthecoolant A. Low coolant level in the regulatestherefrigerationFreon is used, the process itself ter from the surface of the me- system. pumping system. head pressure by varying flowrequires a device called a re- dia cools the remaining water Thepumpmustsupply 3. Lowinlet/highoutlet of coolant to the refrigerationfrigerationcondenser which which drops into the sump for pressure as well as flow in suf- pressure. condenser.Thisvalveisad-changes hot, vapor-rich, Freon recirculationthroughthe ficient quantity to push coolant A. Openbypassvalveon justed to give sufficient refrig-gasbackintoliquidFreon drycleaning machines refrig- through the components that pumping system. eration head pressure for effi-whichisconstantlyrecycled eration condenser. requirecoolingonthe 4. Lowinlet/lowoutlet cientoperationoftheduring the drying segment of 3. Chiller. Water, or a mix- drycleaning machine (on most pressure. refrigeration system.the drycleaning cycle. ture of water and glycol (this machines this would include A. Pump is off. When scale builds up in theInalmosteverycasethis mixture is called a brine), is cir- not only the refrigeration con- B. Clogged inlet strainer. refrigerationcondenserpastcondenser is cooled by a liquid culated by a pump through the denser but also the still con- 5. High inlet temperature/ the point that the normal ad-(there are a few air-cooled con- drycleaning machines refrig- denserandsolventcooler), high outlet temperature. justment of the head pressuredensers which are not the topic eration condenser, cooled by a and in the case of water towers A.Watertowerfannot adjusting valve can compen-of this article). separate refrigeration system and chillers, also back to the working/chillerrefrigeration sate for, many drycleaners sim-Hot, compressed Freon gas and recirculated through the tower or chiller sump which system faulty. ply open the valve wider in theis forced by the refrigeration drycleaning machines refrig- are often located on the roof. B. Pump is off. very mistaken belief they havecompressor into the refrigeration eration condenser.Unfortunately,thereisno 6. Slightly higher than nor- actuallyfixedsomething.condenser where it is cooled No matter what method is hard or fast rule for what the malinlettemperature/high What they have actually doneand condensed by water used for cooling and circulat- pressure readings should be. outlet temperature. is kicked the can down the(called a coolant). ing the coolant through the re- The best method for obtaining A. Heavy scale build-uproad and will pay a lot of ex-In this case we are transfer- frigeration condenser, the effi- the numbers is to note for a build-up of scale inside the tra money in solvent and en-ring the heat from a vapor rich, ciencyoftheprocessis future reference the dryclean- piping of the drycleaning ma- ergy. hot, compressed Freon gas into dependent on two factors: ing machine inlet and outlet chine. The accompanying illustra-thecoolantflowingthrough A. Coolantflow. The pressureandtemperature B. Excessive heat sourcetion shows a schematic for athe refrigeration condenser in amountofcoolantmoving readings when the drycleaning still boil over or steam sweep typical cooling water installa-much the same manner as the through the condenser. valveopen;steamsupply tion (Figure 1) for use with avalvetosteamboostcoilor water tower or chiller with theCOOLING SYSTEM PIPING carbon adsorber. addition of valves 1,2,3 which areBack to the drycleaning ma- used when city water hook-upPRESSURE GAGES AND THERMOMETERS chine operation. is included in the installation.SHOULD BE INSTALLED IN A WELL LITHIGHLY VISIBLE LOCATION OUTLET WATER TOWER Problems with the cooling Thiscitywaterhook-upCITY WATER SETTINGS TEMPERATURE OUTLET OR system are most likely to ap- provides an emergency back-ALL VALVES SHOWN SET FOR NORMALPRESSURE CHILLER pear during the dry cycle. To up for continuing operationsOPERATIONS. TO SWITCH TO CITY WATER be more specific, towards the when there is a failure in theREVERSE THE SETTINGS ON VALVES 1 THRU 5 AND FULLY CLOSE VALVE 6 1 end of the dry cycle when the normal cooling system (it willdrycleaning machine goes into not help if excessive internalBY-PASS cool down mode. scaling is the cause of the prob-VALVE 6 INLETLEFT PARTIALY TEMPERATURE During the drying mode, a lem).OPEN INLETPRESSURE heat exchanger coil is transfer- Bruce Grossman is the chief ofMACHINE INLET ring much of the heat from the R&D for EZtimers Manufactur-MINIMUM AND MAXIMUMREADINGSSTRAINER 2 3 Freontotheairstreamand ing, the maker of the EZ Level re-PRESSURE IN-PRESSURE OUT=MIN. 20 PSI NEW VALVES only a small portion of the heat turn tank water level control thatCOULD BE LESS WITH COLDER COOLANTTEMPERATURE IN=MAX 75 F. 5AND PIPINGload is being dumped into the replaces the ball float valve inFOR CITY WATER THIS VARIES WITH MACHINE AND TYPE OF4 HOSErefrigeration condenser. the return tank. The Sahara andCONNECTIONCLEANING SOLVENT BEING USEDHOSE CONNECTION In the cool down mode, so- Drop in the Bucket line of highFROMHEAD PRESSURE CONNECTION CITY lenoidsand/ordampers purityseparatorwaterCONTROL VALVE TO DRAIN WATER change the path of Freon flow mister/evaporatorsalongwith(COULD BE LOCATEDON THE WATER INLET REFRIGERATION COOLANT and almost the entire heat load the Tattler steam trap tester areON SOME MACHINES) CONDENSER PUMP is now dumped into the refrig- also part of the EZtimer producteration condenser. line. For more information, visitA classic symptom of this www.eztimers.com. Address anySTILL PUMP INLET type of problem is indicated by questionsorcommentsetoSOLVENT CONDENSERSTRAINERCOOLER the refrigeration compressor go- bruce@eztimers.comorcalling into a high pressure condi- (702) 376-6693.'