Carrier 16JT Series Start Up & Operation Manual

Carrier 16JT Series Start Up & Operation Manual Manual pdf 29 page image

Actions After Abnormal Shutdown — Abnormalstop occurs automatically when any of the safety devices inTable 8 sense a condition which might be potentially dam-aging to the chiller. When this happens the steam valve closescompletely, the alarm buzzer sounds, and the type of prob-lem is indicated by one of the three fault lights. Also, boththe Stop and Run lights will be on.The buzzer can be silenced and the circuit reset for restartby depressing the Stop button, but this should be done onlyafter noting which fault light is on; or the alarm buzzer stopbutton may be depressed to silence the buzzer while the con-trol circuit remains in a shutdown alarm mode for trouble-shooting. If the fault is a type which does not allow shut-down dilution, the condition should be corrected and the chillereither restarted, or started and stopped for normaldilution, as quickly as possible to avoid solution crystalli-zation when the machine cools down.Actions After Power Interruption — If the controlpower is interrupted during operation, the chiller stops im-mediately without the normal shutdown sequence and dilu-tion. The capacity control valve might be open so the steamsupply valve should be closed immediately.Solution crystallization can occur if the concentration ishigh (e.g., chiller was operating with a relatively large load).If so, depress the Start button to restart the machine as soonas possible after the power is restored. The machine will notrestart automatically when power is recovered. If the chillercannot be operated because of crystallization, follow the de-crystallization instructions in the Maintenance Procedures sec-tion, page 40.Table 8 —Automatic Stop Safety DevicesCONDITION CONTROL SAFETY SHUTDOWN SAFETYSYMBOL RELAY DILUTION INDICATORLow chilled water flow (below 50%) 69CW CWX No LD1Low chilled water temperature (below 36 F [2 C]) 26CW CWX No LD1Chilled water pump auxiliary contact 88EP CWX No LD1Cooling water pump auxiliary contact 88CP CWX No LD1Solution pump motor high temperature 26SP 26MX No LD2Refrigerant pump motor high temperature 26RP 26MX No LD2Solution pump motor current overload 51SP 26MX No LD2Refrigerant pump motor current overload 51RP 26MX No LD2High-stage generator high pressure (above −.8 in. Hg [−20 mm]) 63GH 63GX Yes LD3High-stage generator high temperature (above 338 F [170 C]) 26GH 63GX Yes LD3High absorber pressure (above — 400 mm Hg [−15.8 in. Hg]) ABS ABSX No NONEPERIODIC SCHEDULED MAINTENANCENormal preventive maintenance for 16JT absorption chill-ers requires periodic, scheduled inspection and service. Eachitem in the list below is detailed in the Maintenance Proce-dures section.Every Day of Operation1. Log machine and sytem readings.2. Exhaust purge.Every Month of Operation1. Determine absorber loss.2. Determine noncondensable accumulation rate.3. Check capacity control adjustment.Every 2 Months of Operation1. Check low-temperature cutout.2. Check Cycle-Guard™ operation.Every 6 Months of Operation1. Check refrigerant charge.2. Check octyl alcohol.Every Year of Operation1. Have solution analyzed.2. Check tubes for scale and fouling.Every 3 Years of Operation — Replace service valvediaphragms.Every 5 Years or 20,000 Hours of Operation —(Whichever comes first.)1. Inspect hermetic pumps.2. Filter or regenerate the solution if necessary.MAINTENANCE PROCEDURESLog Sheets — Readings of machine and system pressure-temperature conditions should be recorded daily to aid theoperator in recognizing both normal and abnormal machineconditions. The record also aids in planning a preventive main-tenance schedule and in diagnosing machine problems. A typi-cal log sheet is shown in Fig. 24.29