Carrier 16JT Series Start Up & Operation Manual

Carrier 16JT Series Start Up & Operation Manual Manual pdf 31 page image

Purge Manual Exhaust Procedure (Fig. 25) —See also Machine Description section, pages 3-9, for expla-nation of the purge operation, component identification, andillustrations.NOTE: The following does not apply to optional vacuumpump operation.NEVER LEAVE the machine during purging opera-tion. A failure to close the exhaust valve will disable themachine, and could cause crystallization of thesolution.OPERATE THE VALVES in the correct sequence.NEVER LET AIR leak into the machine.MAKE SURE that the tip of the vinyl tube is at the bot-tom of the plastic bottle at all times.NEVER SPILL any solution from the plastic bottle.If spilled on personnel or the floor, follow the warningpertaining to Handling Lithium Bromide Solution,page 21.1. Exhaust purge only when machine and solution pump areoperating, because the exhaust pressure is supplied by thesolution pump.2. Keep end of plastic tube below the liquid level in plasticbottle.3. Close the solution return valve.4. Wait approximately 5 minutes for storage chamber pres-sure to rise above atmospheric.5. Slowly open the exhaust valve. If the liquid level in theexhaust bottle drops, close valve and wait approximately2 minutes.6. Slowly reopen the exhaust valve. If bubbles appear in theexhaust bottle, leave exhaust valve open until bubbles stopand solution level in bottle begins to rise. Close valve;purge is now exhausted.7. Open the solution return valve to resume purgeoperation.8. Slowly open the exhaust valve and allow solution in thebottle to be drawn into the purge tube. Lower the solutionlevel until bottle is one-third to one-half full. Close ex-haust valve before solution level in bottle nears the tubeend. Do not allow air to be drawn into the purge tube.9. Log the date and time of purge evacuation to provide anindication of changes in the rate of noncondensableaccumulation.Absorber Loss Determination — Take absorberloss readings when machine is operating with stabletemperatures.1. Make sure that Cycle-Guard™ valve is closed andhas not operated for at least 10 minutes before takingreadings.2. Fill thermometer wells on discharge lines of solution andrefrigerant pumps with oil or heat conductive compoundand insert thermometers.3. Take refrigerant and solution samples (see Solution or Re-frigerant Sampling, page 34), and determine the specificgravity and temperature of each sample. The samples canbe returned to the machine through the purge exhaust bottle.4. Using the equilibrium diagram (Fig. 22A or 22B), plotthe intersection point of the specific gravity and tem-perature of the solution sample. Extend this pointhorizontally to the right and read the saturation tempera-ture. Repeat with refrigerant sample, using Fig. 26A or26B and reading to the left for saturation temperature.5. Subtract the solution saturation temperature from the re-frigerant saturation temperature. The difference is the ab-sorber loss. Repeat the readings with a second sample toverify steady state conditions. (On larger chillers with mul-tiple solution pumps, determine saturation temperature foreach pump.) If the absorber loss is greater than 5° F(3° C), machine evacuation is necessary because exces-sive noncondensables may interfere with normal opera-tion before they can be removed by the purge (see Ma-chine Evacuation section, page 33).For probable causes and suggested remedies for high ab-sorber loss, refer to the Troubleshooting Guide, pages 41 and42.Noncondensable Accumulation Rate — The mostimportant maintenance item on the absorption machine isthe maintenance of machine vacuum within acceptable lim-its. Machine vacuum tightness can be checked by determin-ing the rate at which noncondensables accumulate. Somenoncondensables are normally generated within the ma-chine; but an air leak or the need for additional inhibitor isindicated if the accumulation rate increases.After machine evacuation or other service, operate ma-chine for at least 200 hours before determining noncondens-able accumulation rate. Then proceed as follows (Fig. 27):1. Fill a length of flexible tubing with water and connect tothe purge exhaust connection. Insert free end into a con-tainer of water. Exhaust purge completely (see Purge ManualExhaust Procedure section, on this page).2. Operate machine for 24 hours with purge operatingnormally.3. Fill a 2-pint (1000 cm3 ) bottle with water and invert it ina clean container filled with water.4. Insert the free end of water-filled hose into the bottle.5. Follow the purge exhaust procedure. Noncondensables dis-place water in the inverted bottle. Continue until bub-bling in the bottle ceases and only solution flows fromexhaust tubing.Fig. 25 — Purge Exhaust Assembly31