CHILLER MAINTENANCE CHECKLIST AND DAILY LOGS
Tracking daily operations is half the battle when it comes to maintenance. Keeping a detailed log is the most efficient means of understanding how your chiller is doing.
These logs should include necessary information like flow rates, operating temperatures, pressures, and fluid levels. There are many downloadable log sheets to keep these numbers up to date. Remote monitoring systems are also very popular in supporting daily logs on machinery. It requires less time and can update as frequently as necessary since it is often an automated system. Many times, remote monitoring systems can automate insight reports as well, for real-time diagnostics on your chillers.
Performing chiller maintenance is a must. Below are a few items to add to your general maintenance checklist to ensure you don’t miss a step.
Note refrigerant and oil levels
Inspect fan control system
Check evaporator water temperature differential
Measure condenser fan motor volts/amps, where applicable
Check water flow through evaporator
Measure condenser and evaporator pressures
Check operation of controls
Leak-Measure and verify refrigerant, water, oil, etc.
Check safety control settings
Check operating control settings
Inspect compressor motor operation
Inspect compressor motor efficiency
Check compressor motor volts/amps
Secure all cap tubes from chafing
Check crankcase heater operation
Check cap control setting/operation
Inspect condenser/evaporator controls air and water
Inspect moisture indicator
Check low/high and oil pressures
Inspect fan and assembly rotations, etc.
Check chill water temperature control
Inspect belts, sheaves – tension and alignment
Check fan speed controllers
Listen and look for unusual noises/vibrations
Check structural integrity of unit
Compare tonnage being produced vs electricity being consumed
Note: Chiller maintenance will vary from manufacturer to manufacturer and should be assessed on a case by case basis.
KEEPING TUBES CLEAN
Tubes are the main path for heat transfer in chillers and can be largely responsible for the performance of your industrial chiller. Contaminants and impurities can increase thermal resistance. This would reduce heat transfer efficiency as the resistance would affect the consistencies in approach temperatures in the chiller. It is important to brush these tubes at least once per year. With a strong monitoring system, you’ll be able to see problems before they occur. Giving you the opportunity to clean the tubes before they become too much of a problem.
TREAT CONDENSER WATER
Keeping the condenser water clean is important for both boilers and chillers maintenance for many of the same reasons. Corrosion and scaling both reduce efficiency. Both of which, build up over time if the water is not well-treated. Untreated can result in higher condenser pressures, impeded heat transfers and inconsistencies in water temperature and water flow. Regular chemical treatments can help keep the water clean and filters should be replaced often.
ANALYZE COMPRESSOR OIL
If you’re working with a new chiller, it is standard practice to do an oil and filter change after the first year. As well as, analyze the oil to determine the frequency of future oil changes. The dirtier, the more frequently your system will likely require a change. We also recommend doing a spectrometric chemical analysis of this oil once a year. This will help acquaint you with your system and its potential issues. Learning how to address various problems, from high water content to the size of the particles contaminating the oil, can be invaluable.
There are also many chillers that have completely eliminated oil from the equation, thus lowering potential chiller maintenance costs.
PURGE THE SYSTEM
This process is only for low pressure machines. It involves purging the system of non-condensable gases. These gasses can be produced in a chiller on the low pressure side where there is a pump or filter. Because the evaporators operate in a vacuum, these non-condensable elements are able to leak in. Ensure the air and moisture are at an all-time low by purging.
INCREASE CONDENSER WATER TEMPERATURE
Raising the temperature of chilled water being supplied to a facilities air handling units will improve its efficiency.
CONTROL THE FLOW
As with the temperature of the water, the flow of it also plays a big impact on the efficiency of your boiler. The chilled water flow rate must be above 3 feet per second and below 12 feet per second. If the flow falls below 3 feet per second, your flow may become laminae. If the flow rises above 12 feet per second, vibration and noise lead to the ideal environment of tube erosion.
CUT COSTS WITH VARIABLE FREQUENCY DRIVES (VFD)
Variable Frequency Drives (VFDs) motor speed matches the needed load, offering a more cost and energy-efficient way to operate. They also offer a softer start and lower in-rush of current.
Chillers are a complex unit. In tandem with professional help, you’ll be able to keep your unit operating efficiently. Whether you’re in need of a consultation, repair, strategic chillers maintenance, rentals, or parts, we’re here to help. Reach out to the professionals at Mistrijje.com to see what we can do for you.
CHILLER SAFETY CONTROLS
Usually, a chiller consists of a compressor, an evaporator, and condensers. Each chiller requires different setting that corresponds to the load for maximum efficiency. Every chiller has safety controls that are designed to protect the cooling system from harm. This protects against low refrigerant temperature, low oil pressure, or high condensing pressure.
Some of these controls include capacity controls and refrigerant flow controls. Capacity controls maintain the temperature of the chilled water and refrigerant flow controls are set in correspondence with the compressor used. In the event that these controls fail, the system can be set to shut down. This avoids more serious machine damage that could affect the health of those around.
CHILLER MAINTENANCE CHECKLIST HELP
From reciprocating, rotary screw, centrifugal and frictionless centrifugal to absorption chillers there are many different maintenance requirements. As always, follow your manufacturers recommendations and work with a professional to ensure you don’t miss a step.