[ad_1]
Complete chiller upkeep can prolong the life of kit, enhance its reliability, save scarce refrigerant, and cut back vitality and different working prices whereas shopping for you time to work out a long-range plan.
Testing and inspection
You will want design specs, tools manuals and restore historical past for every part, and a value historical past for buy, repairs and operation. Are some elements getting extra repairs and costing greater than others? Are annual vitality prices rising sooner than charge will increase? Have current prices exceeded previous prices? Are your prices greater than prices at different comparable services? Are they greater than averages out of your skilled affiliation? You will wish to do that testing yearly or two, so arrange a recordkeeping system if you do not have one. Determine if you wish to check in-house or use an inspection company with the instrumentation {and professional} know-how.
In the event you determine on knowledgeable, your upkeep workers must activate and set the system for the inspector, change drive ratios, add dampers if wanted, exchange worn elements, and present the inspector the place panels and tools are positioned. Inform your tools vendor and consulting engineer concerning the inspection to allow them to present design details about the unique system.
You will must conduct air steadiness, water steadiness and sound testing. The elements examined are:
• air-moving tools
• provide and exhaust followers
• diffusers and grilles
• water-balance parts
• circulating water pumps
• cooling towers
• chillers
• air- and water-cooled condensers
• ducting.
A steadiness check on a packaged unit takes a couple of day; on built-up models, not less than two or three days or extra for multi-zone or multi-unit techniques. All testing devices must be calibrated inside six months of testing.
Air-balance testing
You will must do air-balance testing first as a result of system air have to be in steadiness for water-balance testing to proceed correctly. Particular instruments and instrumentation used are:
• scorching wire anemometer
• rotating vane anemometer
• self-timing velocity counter
• pitot tubes 18-60 inches
• velocity meters
• clamp-on ammeter
• static suggestions
• a number of 8-inch stem thermometers
• motorized psychrometer
• hand sling psychrometer
• micromanometer
• inclined gages 3-inch and 10-inch
• multi-point floor pyrometer
• combustion check units
• electrical drill motors
• balancing hoods
• pyrometer
• recording thermometers
• smoke gun
• and two-way radios.
The method contains testing and adjusting blower rpm to design; motor precise vs. full load amps; pitot tube traverse of provide ducts and design CFM of followers; system provide and exhaust static pressures; design vs. precise recirculating air; design CFM of out of doors air; getting into moist and dry bulb air temperatures; exiting moist and dry bulb air temperatures; adjusting all provide and return air ducts and zones to design CFM; adjusting every diffuser grille and register to inside plus or minus 10 p.c of design necessities; FPM velocity at every diffuser, grille and register; and changes to reduce drafts. Additionally, all controls have to be checked for correct calibration and settings.
Water-balance testing
Water-balance testing must be accomplished solely after air-balance testing is full and the air system is correctly balanced. Along with the beforehand talked about instruments, you may want water-pressure gages, a differential gage set for studying orifice and venturi stations, and meter units for studying velocity and move. You will additionally want vibration analyzers, and air and water air pollution check tools.
The water-balancing course of contains:
• beginning and setting all controls to correct settings
• eradicating and cleansing strainers
• analyzing water for correct therapy and cleansing
• checking pump rotation
• verifying that enlargement tanks are charged and never air or water sure
• checking air vents at prime of water system to make sure that they’re put in and dealing
• setting temperature controls to full cooling
• checking working temperatures of chiller and boilers
• ensuring that chilled water pumps are calibrated for correct GPM supply
• checking current and return water temperatures
• checking chiller water move stress
• monitoring water and steadiness temperatures at inlet aspect of cooling coils
• monitoring stress drop by way of coils and move charge
• monitoring pump working suction and discharge pressures.
Record all pump mechanical specs, motor rated and working amps and water metering machine readings.
Sound testing
Outdated techniques loosen up, get misaligned or maybe weren’t accurately sound insulated when put in. Thorough sound testing utilizing decibel meters and vibration evaluation is part of the testing and inspection. Sound checks embrace background sound degree with tools off, complete sound degree with tools on, and correction of sound degree to tools solely. Sound ranges are in contrast with constructing specs utilizing readings in decibels. Tools vibration absorbers and insulation are checked for effectiveness.
Chiller restore
Earlier than finishing repairs, be sure you’ve complied with all security precautions, comparable to carrying private protecting tools and performing lockout and tagout procedures. The commonest repairs required because of check knowledge are cleansing and minor changes. All techniques want filter and duct cleansing on the air aspect not less than yearly. If the filters are tight and duct joints are correctly sealed or taped, cleansing will not be a giant job, and the air system will likely be extra environment friendly. Water, oil and refrigerant pattern checks point out the tools’s situation. If there’s water within the refrigerant, seals must be changed. If there’s refrigerant, rusted steel or steel filings within the oil pattern, examine the seals, piping, bearings and rotary or reciprocating parts for put on.
Drive gears, bearings, belts and couplings will final for years with an excellent PM plan. They need to be checked not less than yearly, even when fluids do not point out an issue. V-belt drives must be tight on the underside and slack on prime between the sheaves for extra arc of contact and fewer slipping. If the sheave groove bottoms are vibrant, the V-belts are bottoming out and can slip. Both change the V-belts in the event that they’re worn or change the sheaves if they have been slipping and the V-grooves are worn. Worn sheaves will rapidly smash new V-belts.
If belt plies are separated, change the belts. In the event that they’re free sufficient in order that urgent them within the middle between the sheaves strikes them multiple thickness of the belt, realign them with a straight edge; then tighten them. Loosen the motor anchor bolts, again the motor away from the pushed sheave by turning the motor body adjusting screw below the motor till the belts are correctly tensioned.
Bearings and gears protected with the correct quantity and kind of fresh lubricant can run hotter than you possibly can contact — greater than 110 levels — for years with out issues. Even new lubricant will not be completely clear, so in-line oil filters are an excellent funding. Common filter inspection and alter will uncover issues earlier than they change into critical. Pillow block bearings shouldn’t be greased too typically. Normally, a couple of photographs as soon as each three to 6 months is sufficient. Seals may be broken by overlubrication. Take away the reduction plug earlier than including grease, and permit the bearing to run awhile to discharge the surplus. Examine the colour and texture for indicators of rust, steel, water or different contamination. Rubber gloves and security glasses or full face safety must be worn the place acidic refrigerant may be current.
Security checks
Common PM security and electrical checks are an necessary a part of your annual check and inspection course of. Your system documentation will present:
• the place these units are positioned
• what checks to carry out
• tips on how to carry out them, and the way typically
• what instruments you want.
Troubleshooting
Begin by speaking to the requester or tenant to get an outline of the issue. For instance, if the issue is in a package deal heating and A/C unit, discover out if it is a cooling or heating drawback, or each. All the time begin with the plain:
• Is energy attending to the system?
• Are the fuses and fused swap contacts good?
• Are circuit breaker contacts clear and tight?
If the heating works however the cooling does not, this most likely eliminates the heating circuit controls. Observe operation to verify this. If you’ve narrowed the probabilities, hop-scotch {the electrical} circuit within the space of the issue with a voltmeter, set to the circuit’s voltage vary. Preserve the circuit diagram useful — normally inside {the electrical} panel door or within the working and repair handbook. Generally a microswitch or relay sticks open. In the event you discover an open swap — no voltage the place a voltage must be current — which must be closed when the circuit is energized, faucet it a couple of instances with an insulated screwdriver deal with. If this causes the system to renew operation, flip off the system, flip it again on, and repeat the check.
If this confirms that the swap is defective, exchange it. Then strive the system once more to ensure it is the one drawback, and that the alternative was accomplished correctly. When utilizing a tester, it is good follow to make use of an alligator clip on one lead. Just one hand is required to do the testing with the opposite probe.
Damper leakage
Many hassle calls from improper temperature are from too excessive a temperature within the duct or temperature time lag. Too excessive a temperature could also be attributable to delivering blended air at, say, 62 levels, when it must be 54-58 levels. Temperature time lag is simply too lengthy a time to chill the air in the course of the modulating interval leading to a sense of discomfort. As a lot as 35 p.c of month-to-month working prices may be attributable to compensation for leakage. To appropriate this drawback and decrease your working prices on the similar time, test the zone mixing dampers for leakage. Delicate foam plastic on the main edges of blades seals them higher when they’re closed. Leaking dampers additionally improve the noise degree.
Handbook dampers must be put in off the face of multi-zone models; it’s going to present actual adjustment of complete move. Diffuser, aspect wall or computerized dampers are solely meant for advantageous adjustment. Examine their linkages and vary of movement. You can’t subject air steadiness your system with out the best variety of dampers in the best place.
Preventive/predictive upkeep
Routine PM for many ceaselessly used chillers — electrical centrifugal, electrical reciprocating and absorption — contains annual lube oil, oil filter aspect and refrigerant filter-dryer cartridge adjustments. Oil sampling and inspection for bearing or gear put on particles is completed in addition to checking magnetic plugs within the oil reservoir.
Rust particles originate within the condenser and point out air and moisture within the refrigerant system. Chemical evaluation of each the refrigerant and oil yield helpful details about the presence and supply of contaminants. Fluid leak checks are made twice a yr, until low fluid ranges point out the necessity to check extra ceaselessly. Leaks within the refrigerant system of air and non-condensable gases are finest dealt with by common purges. Clear tubes after each season and examine for corrosion, erosion, stress corrosion and fatigue brought on by thermal stress. All the time use a water therapy specialist for preliminary charging of a brand new system and for steady monitoring. Present testing devices can detect tube cracks early; exchange the tubes as quickly as they’re found.
The water answer of lithium bromide used as a refrigerant in absorption chillers may be very corrosive. It assaults metal, copper and copper alloys in 300 F air or greater. Use corrosion inhibitors within the manufacturer-recommended vary; test it twice a season. Additionally test alkalinity and presence of ammonia, copper or iron which can be current in small (elements per million) portions. Water strainers and traps must be checked, cleaned and adjusted yearly.
Vibration evaluation of rotating tools on the bearings must be accomplished throughout operation to test for bearing and kit put on, bent shafts, imbalance in fan and blower blades, and coupling or different misalignment in air dealing with tools, water pumps, chillers and motors. Infrared scanning {of electrical} switches, circuit breakers, motors and kit packing containers will detect overheating circumstances and assist determine free or corroded electrical contacts, scorching motor windings, dangerous bearings and gears and low oil ranges. These predictive upkeep inspections must be accomplished not less than yearly after establishing a baseline or regular studying at every level — and do them earlier than the main shutdowns so findings may be analyzed in time to determine what repairs are required. This strategy permits lead time for acquiring spares, particular instruments and tools and planning the work.
[ad_2]
BY by GAHZLY
#Chiller #Efficiency #Testing #Inspection #Upkeep
Leave a Reply