Core Services eBook Chapter 3 Preventive Maintenance.pdf

EmersonNetworkPower.com

What You Need to Know About Your Critical Infrastructure

Liebert Services eBook Series

Executive Summary

What is Preventive Maintenance?

Why is Preventive Maintenance Important?

What is the Return on Investment for Preventive Maintenance?

Preventive Maintenance and Power

How Often is Preventive Maintenance for Power Needed?

Preventive Maintenance Checklist for Power

Batteries are Important to Your UPS

Preventive Maintenance and Cooling

How Often is Preventive Maintenance for Cooling Needed?

Preventive Maintenance Checklist for Cooling

When to Get a Professional Involved

Conclusion

Chapter Three Preventive Maintenance

Emerson Network Power | What You Need to Know About Your Critical Infrastructure


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Executive SummaryIn our last chapter, we addressed some of the specific issues data center managers face in their

facility, and highlighted how testing and assessments can prepare them to respond, identify

risks, and improve operations. In this chapter, we address preventive maintenance, and discuss

why it is critically important to a data center.

What is Preventive Maintenance?In our previous chapter, we discussed how testing and assessments can help data center

managers avoid issues that might compromise efficiency, optimization and availability in

their facilities, but in reality, testing and assessments is just part of the solution preventive

maintenance is also a critical component of every data center.

Preventive maintenance is used to ensure maximum reliability of data center equipment by

providing systematic inspections, detection and correction of incipient failures, either before

they occur or before they develop into major defects that result in costly downtime. Preventive

maintenance can include activities such as inspections, tests, measurements, adjustments, parts

replacement, and general housekeeping practices.

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Executive Summary












Conclusion

Preventive maintenance is a critical factor in data center performance.



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Why is Preventive Maintenance Important?As organizations become increasingly dependent on data center systems, there is a need for

greater reliability in the critical infrastructure and the reliability of a system only lasts as long

as the shortest component life in the unit. Preventive maintenance is critical for minimizing

unit-related failures, maintaining system cooling efficiencies, and managing operating costs.


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Executive Summary












Conclusion

Kevin McCalla, Vice President of Marketing, Liebert Services,

answers IT preventive maintenance questions in this video.



What is the Return on Investment of Preventive Maintenance?The number of preventive maintenance visits in a data center has a substantial impact on

system reliability and less downtime and that translates into direct savings for data center

managers.

The return on investment for preventive maintenance can be observed by calculating the

Mean Time Between Failure (MTBF). MTBF is an industry recognized measure of availability

that uses the number and types of failures that products actually experience in real applications.

In general, a higher MTBF number, stated in hours, indicates a more available unit. For example,

a UPS unit with an MTBF of 2 million hours is more available than a unit with an MTBF of

1 million hours.

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The Business Case for Regular Maintenance

Number of Annual Preventive Maintenance Visits

0 1 2 3 4

60x increase in MTBF

50x

40x

30x

20x

10x

reventi

2

23x

Number of A

1

Annual P

10x

tenance

3

ive Maint

37x

4

60x in

50x

40x

30x

20x

10x

e Visits

51x

Increase in Mean Time Between Failures

Regular preventive maintenance increases the mean time between failures (MTBF).

For instance, the mean time between failures for a system that receives 1 annual PM is 10 times greater than a system that receives 0 PMs.

By contrast, a system that receives 4 annual PMs, as opposed to 0 PMs, increases its duration between failures by 51 times.

1 Data is based on Mean Time Between Failure analysis for three phase UPS systems ( 100kVA) with a service agreement between 2002-2007.

1x


Continue.. .Regular preventive maintenance increases the MTBF. For example, the MTBF for a system that receives one annual preventive maintenance visit is ten times greater than a system that receives

zero preventive maintenance visits. By contrast, a system that receives four annual preventive

maintenance visits, as opposed to zero visits, increases its duration between failures by 51 times.

Two key statistics are incorporated into MTBF; cumulative operating hours and number of

unit-related failures, to calculate average availability across all units in a given population.

The formula is as follows:cumulative operating hours

number of outages + 1MTFB =

Number of Annual Preventive Maintenance Visits

Data is based on a Mean Time Between Failure analysis for three-phase UPS

systems (>100kVA) with a service agreement between 2002-2007.

Executive Summary












Conclusion



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Preventive Maintenance and PowerFor many organizations, the IT infrastructure has evolved into an interdependent business-critical

network that includes data, applications, storage, servers and networking. A power failure at any

point along the network can impact the entire operation and have serious consequences for

the business.

To keep running through power outages, utility spikes and other unforeseeable power issues, critical

systems are dependent on the reliability of the Uninterruptible Power Supply (UPS) systems.

UPS systems are designed to offer the utmost reliability and performance, but in reality, failures

still occur. Data center managers who are proactive with preventive maintenance will greatly

reduce their chances of downtime.

Preventive maintenance programs maximize the reliability and performance of the UPS systems

by providing systematic inspections, detection and correction of incipient failures.


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Executive Summary












Conclusion

Liebert NXL color touch screen display allows the users to view needed

operational information.



Check power capacitors for swelling or

leaking oil and DC capacitor vent caps

that have extruded more than 1/8.

Record all voltage and current meter

readings on the module control cabinet

or the system control cabinet.

Measure and record harmonic trap filter

currents.

Check all breakers, temperature,

connections, and associated controls.

Repair and/or report all high temperature areas.

Complete visual inspection of the

equipment including subassemblies, wiring

harnesses, contacts, cables, and major

components.

Check air filters for cleanliness.

Check module(s) completely for rectifier and

inverter snubber boards for discoloration.

Semi-Annual Service

Power equipment should be inspected one or two times annually.

Typical tasks performed during a Semi-Annual service visit include:

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How Often is Preventive Maintenance for Power Needed?The frequency of preventive maintenance depends on the type of UPS. Small UPS devices should

be inspected annually, but medium and large systems should be inspected at least twice a year,

sometimes more. Below is a checklist for semi-annual and annual preventive maintenance service.


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Conclusion



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Annual Service

Typical tasks performed during an annual service typically include all the tasks performed

during a semi-annual visit plus the following:

Check inverter and rectifier snubbers for burned or broken wires.

Ensure all nuts, bolts, screws, and connectors for tightness and heat discoloration.

Verify fuses on the DC capacitor deck for continuity (if applicable).

With customer approval, perform operational test of the system including unit transfer

and battery discharge.

Check and record all electronics and bring to system specifications as needed.

Install or perform any Engineering Field Change Notices (FCN) as needed.

Measure and record all low-voltage power supply levels.

Measure and record phase-to-phase input voltage and currents.

Review system performance with customer to address any questions and to schedule repairs.

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Conclusion



Preventive Maintenance Checklist for Power What are Service Providers Evaluating?

Some common preventive maintenance checks should include:

Power Semiconductors During an annual preventive maintenance cycle, semiconductor

devices should be visually inspected for corrosion and breaks to the hermetic seal. If corrosion

or seal damage is found, the device should be replaced.

Electrolytic DC Capacitors Experience proves that capacitors should be replaced significantly

before the end of their rated service life. This helps account for variations in ambient temperature,

air-borne contaminants and other environmental factors.

Oil-Filled AC Capacitors As oil-filled capacitors approach their design life, they are subject to

the internal breakdown of the soggy foils and possible loss of capacitance. Its recommended that all

oil-filled capacitors be inspected and those within six months of their expected life should be replaced.

Circuit Boards There is no rated service life on the components

specified for use on the circuit boards. Circuit boards with problems should

be removed and returned to the manufacturing plant for repair and test.

Before they are returned to service, it is recommended they have all

outstanding revisions incorporated and then undergo system testing.

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Conclusion



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Batteries are Important to Your UPS Batteries are an important element to a data centers UPS and

unfortunately, theyre often overlooked. Semi-annual and annual

preventive maintenance will typically include the inspection of

batteries, but it is recommended that data center managers also

implement a preventive maintenance program specifically for

batteries in their system. Stay tuned for more information on

batteries and battery monitoring in our next chapter.

Preventive Maintenance and CoolingPreventive maintenance is also critical for maintaining

system cooling efficiencies, operating costs, and minimizing

potential downtime. Cooling modules have moving parts

that eventually wear out. Preventive maintenance ensures

that these components last as long as possible. It also ensures

these components perform within their originally designed

operating parameters, allowing data center managers the

opportunity to replace components before they fail.

How Often is Preventive Maintenance for Cooling Needed?Like preventive maintenance for UPS systems, the frequency and task for cooling preventive

maintenance can vary depending on the model. The factory recommends at least four preventive

maintenance visits per year, replacing belts and filters as necessary (typically two times per year for

filters and one time per year for belts).


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Conclusion



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Preventive Maintenance Checklist for CoolingWhat are Service Providers Evaluating?

Some common preventive maintenance checks should include:

Air filters: Clogged air filters reduce the airflow through the systems and increase the load on the

blower drive system. This may result in reduced system cooling performance, higher operating

costs, reduced component life of the blower drive systems, and higher operating temperatures

of the equipment in the data center. These higher operating temperatures may be very localized

and hard to detect within a data center due to irregular air flow patterns. Similarly, substitution

of non-OEM filters may also change performance of the system. Lower cost substitute filters may

collapse (where the pleats fall flat against the downstream face of the filter box) if they have not

been designed for the air flow of the system. Always use OEM replacement filters when servicing

your equipment.

Blower Drive System: The blower belts, bearings, motors and

wheels need to be inspected regularly. Wear or damage to any of

these components may result in the reduction or loss of airflow

or reduced cooling performance. Again, all of these components

are specifically selected for the performance requirements of

the system, and only OEM replacements should be used. Belts,

specifically, are literally machined to match as a set of two or

three belts so that belt tension is uniform to maximize belt life.

Steam Generating Humidifiers: Humidifiers may be connected with valves and hoses that may

leak and drains may become clogged over time. These components should be inspected regularly.

Steam generating humidifiers are vulnerable to water deposits that can diminish humidifier

performance. Once these deposits form, more power is required to achieve the same level of

humidification, and the assembly begins to deteriorate toward failure.


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Conclusion



Infrared Humidifiers: IR Humidifier bulbs may burn out, diminishing performance. Drains and

pans should be inspected for deposits and clogs. Emerson Network Power offers the VAPURE

humidifier additive which inhibits these deposits from forming. When handling humidifier bulbs,

it is important not to touch the glass bulb with your fingers. The residue from skin oils creates a

hot spot on the bulb that reduces the life of the bulb.

Condensate Drains and Pumps: Confirm

proper pump function and verify drains are

not clogged. Obviously, the combination of a

clogged drain and a failed level sensor results in

pan overflow.

Reheat: Inspect and clean reheat elements.

Inspect and tighten support hardware.

Compressor: Inspect oil level and check for leaks. Compressors running with too much or

too little oil will see diminished service life. Always use the same type of oil supplied with the

compressor from the OEM.

Facility Fluid and Piping: Units connected to facility water or glycol should perform necessary

maintenance to assure the quality of the fluid. Contaminants in these fluids can lead to diminished

performance.

Evaporator Coils: Evaporator coils should be checked periodically to

verify they are clean and free of debris. Dirty coils are less efficient at

removing heat.

Condensers and Dry Coolers: Condenser coils should be checked

periodically to verify they are clean and free of debris. Motor mounts

should be tight. Bearings should be free and in good condition.

Refrigerant lines should be properly supported. Similar to evaporator

coils, dirty condenser coils are less efficient at rejecting heat.

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Executive Summary












Conclusion

Compressor oil levels should be

checked regularly for maximum

service life.



When to Get a Professional InvolvedMost preventive maintenance measures should be left to a qualified and trained professional.

UPS and batteries contain high voltage, and only qualified personnel should attempt preventive

maintenance or repair. Data center managers can and should provide preventive support by

replacing air filters when dirty, ensuring environmental specifications are met and maintained,

and monitoring the UPS for alarms.

ConclusionIn the current economic environment, many organizations are relying heavily on existing

equipment to maintain operations, making preventive maintenance more important than ever

before. Preventive maintenance is a critical component of every data center, and it should not be

overlooked. Without it, data center managers are compromising the efficiency, optimization and

availability in their facilities.

Liebert Services is committed to helping organizations understand their critical infrastructure,

identify problems, and incorporate solutions. Stay tuned for chapter four in our eBook What

You Need to Know About Your Critical Infrastructure to learn more about batteries and battery

monitoring. Well highlight how organizations can ensure batteries arent the weakest link in the

UPS, and outline a battery preventive maintenance program.


Executive Summary












Conclusion

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