Troubleshooting and Maintaining Lighting Control Systems

Troubleshooting andMaintaining Lighting Control Systems

In this chapter, you will learn about

  • Maintenance activities for a lighting control system
  • Diagnostic and troubleshooting procedures for a lighting control system
  • Troubleshooting power line control (PLC) control devices in a lighting control system

Unfortunately, lighting control systems are rarely “set-’em-and-forget-’em” affairs. There are certain services and tasks required to maintain the system, including its lamps, remote controls, and programming.

This chapter focuses on the maintenance tasks and services you should perform on a customer’s lighting control system to keep a home’s lighting system working as designed, and the procedures used to troubleshoot and diagnose a lighting control system with an emphasis on systems installed on PLC technology.


Maintaining a Lighting Control System

The maintenance activities for a lighting control system primarily involve ensuring the lighting levels and control desired by the homeowner are maintained. The purpose of the lighting control system is to provide the type, mix, and level of lighting the system was designed to produce, all controlled easily. However, there are a number of factors that can contribute to a lighting system failing to perform as expected.

In the context of home technology integration and home automation certifications, the maintenance activities for a lighting control system are

  • Preventive maintenance
  • Control changes
  • Manufacturer upgrades
  • Troubleshooting and diagnostics

Preventive Maintenance

A preventive maintenance plan should be developed and regularly executed for all control systems in an automated home, including the lighting control system. The purpose of a preventive maintenance plan is to maintain the system in proper working order and to prevent or detect problems early on.

At minimum, preventive maintenance should be performed on the lighting control system once a year. Every task in the maintenance plan must be completed and a written record indicating what was done and who did it produced.

The maintenance plan should include, at minimum, the following activities:

  • Checking all connections and visible wiring
  • Cleaning the control panels and keypad controls
  • Cleaning any fans and motors in the control panel
  • Verifying the lighting load of each circuit
  • Applying any control changes or lighting adjustments desired by the homeowner
  • Creating a backup of the control panel programming
  • Updating the system’s maintenance log

Check Connections

The connections at the lighting system control panel should be checked and verified for proper contact. This check should include both a visual check and an electrical check using a multimeter to ensure electrical continuity and voltage for each line in the system.

You should also visually inspect the condition of the exposed wiring for deterioration of the insulation or conductors. If a problem is found, the problem and your recommended solution should be brought to the attention of the homeowner.

Cleaning

The interior of the control panel should be cleaned to remove any dust or other debris that may have accumulated. Avoid using a standard vacuum cleaner to prevent the introduction of high levels of static electricity to the controller’s circuits. Use either a special-purpose vacuum cleaner (the type recommended for cleaning the inside of computers works best) or a can of compressed air to clean the inside of the control panel.

The exterior of the control panel should also be cleaned. First, use a nonstatic cloth (such as the 3M Electronics Cleaning Cloth) to remove any dust on the exterior of the controller and the keypad, if one is present. Use a nonsudsing cleaner to clean the exterior of the controller. In most cases, the manufacturer’s documentation should indicate the acceptable cleaning solutions that can be used. These same procedures should be used to clean the keypad, dimming, and switch controls throughout the home.

Check Fans

If the lighting control system has a cooling fan, verify that the fan is working properly. The fan should be cleaned regularly to ensure proper airflow to the circuits inside the controller. Use compressed air to blow away any dust collected on the fan’s blades. Avoid using any liquids to clean the fan. Also clean the exterior and interior grills, if any, of the fan assembly.

Check Lighting Loads

It is possible that the homeowner may have replaced an original lamp with one that is outside the designed operating limits of a lighting circuit and inadvertently increased the lighting load of the circuit. If the current lighting load of a circuit is outside the operating tolerances, this situation should be explained to the homeowner and the lamp should be replaced with one that brings the circuit into its designed load.

Check with the homeowners to see if they wish to have any or all of the lamps in the home replaced. If they so desire, replace the lamps, retaining any good lamps as spares for the homeowner.

Control Changes

The homeowner may wish to change one or more lighting scene or control level of the lighting system. If so, make the necessary programming changes and thoroughly test the system to the homeowner’s satisfaction.

Also check with the manufacturer for any controller or system upgrades that can be applied. You should understand the affects of any upgrades to the system and make a recommendation to the homeowner on whether or not the upgrade should be applied. Some manufacturers issue accumulative upgrades that allow some upgrade levels to be skipped and others issue incremental upgrades that must be applied in every case. After applying any system upgrades, retest the system thoroughly to ensure it’s functioning properly.

  Note

Many manufacturers issue maintenance bulletins with recommended upgrades. Another good place to find information about upgrades to the system is the manufacturer’s web site.

Back Up the Controller

Regardless of whether programming changes are made or not, a backup of the controller’s programming should be created. In some cases, this may be only a print out of the programming statements or commands. In other cases, it may be possible to create a backup to a removable media (such as a diskette), especially if the controller is programmed from a PC.

A copy of the backup should be kept at the home and another copy should be stored in the project folder off premises.

Maintaining Maintenance Logs

The importance of maintaining a maintenance log that records all maintenance activities is not often realized until some point in the future when a problem arises that can be traced back to a maintenance action performed in the past. The most common types of troubleshooting problems are those caused when another problem is fixed. Maintaining a maintenance log that records every action, repair, upgrade, and even preventive maintenance provides another technician with a history of the types of actions a system has required.

Table 25-1 illustrates an example of a simple maintenance log form and the types of information that should be recorded.

Table 25-1: Sample Preventive Maintenance Log

Date

Activity

Technician

Comments

1/5

Clean controller interior

HH

Dust heavy; should clean more frequently

1/5

Clean controller exterior

HH

Dusty; clean more frequently

1/5

Check wire contracts

HH

Normal

1/5

Continuity check

HH

Normal

1/5

Backup controller

HH

Copy to HO; copy to office


Troubleshooting Lighting Control Systems

Before beginning any other diagnostic or troubleshooting activities, your first action should be to debrief the homeowner on the nature of the problem he or she is experiencing with the lighting system. Especially in an integrated system environment, a problem may be showing up as a lighting issue when, in fact, it could be a problem with another subsystem or the structured wiring. After gaining a full understanding of the problem from the homeowner, you can begin your activities to isolate the problem and repair it.

Debriefing the Homeowner

Feedback from the homeowner is maybe the best way to learn about performance problems on a newly installed lighting control system. Debrief the homeowner to learn if the lighting scenes are still effective; if scheduled lighting scene changes occur when they should; if there are problems with lighting levels in any room, zone, or on a particular fixture; and if the lamp life on a particular fixture or lighting group is less than it should be.

Troubleshooting Lighting Controls

When a problem is identified with a distributed or stand-alone relay or dimmer switch, the best place to start your investigation is at the switch in question. You’ll use a different repair approach on hard-wired switches, stand-alone switches, or PLC switches.

Troubleshooting Hard-Wired Switches

Hard-wired lighting controls generally have one of two problems if they aren’t working correctly: the switch itself is faulty or a problem has developed with its wiring. If the switch is bad, it should be replaced, but never assume that is the only problem. The switch failing could very well be caused by a problem on the alternating current (AC) wiring, such as a short or open circuit. So, check the switch for scorch marks or other causes for its failure, and also verify the characteristics of the AC connections using a multimeter.

Relay switching controls, like those controlling an incandescent lamp, have relatively simple problems and are generally easy to troubleshoot—for example, problems such as a broken toggle switch, no power, or bad wiring. However, dimmer controls can be a bit harder to troubleshoot.

One reason dimmer controls can be harder to troubleshoot is that there are several different types. Further, they have more internal parts to go bad. Table 25-2 lists some of the more common problems that dimming controls may have.

Table 25-2: Troubleshooting Dimmer Controls

Problem

Diagnostic

Troubleshooting

Lamp remains off

Is power available to the dimmer?

Verify the AC connection before checking the dimmer control.

 

Is the circuit breaker tripped or the fuse blown in the electrical panel?

 
 

Is a rotary dimmer or push-button control connected to AC power?

 
 

Is only one dimmer in a room not working?

If shorting around the dimmer powers the lamp, change out the dimmer control.

Lamp remains on

Does the lamp remain on after disconnecting the neutral wire?

The dimmer's thyristor is likely bad. Replace the dimmer control.

Lamps flicker

Are the incandescent lamps flickering and the lighting cannot be controlled up or down?

The dimmer is bad and should be replaced.

Lamps flicker at some adjustment levels

Is there an electronic transformer on the circuit?

A dimmer for incandescent lamps cannot be connected to a leading-edge transformer. The dimmable ballast cannot be connected to a failing-edge transformer.

Dimmer range is limited

Does the dial turn the full distance without adjusting the lamp to its full range?

Change Min or Max setting on dimmer.

Other dimmer performance problems

Is the impedance on the lighting cable 25 kilo-ohms?

Test the impedance on the lines linking the dimmer to the fixtures.

Troubleshooting Stand-alone Lighting Controls

Stand-alone controls that control only a single lamp or multiple lamps connected to a common lighting circuit are much like hard-wired controls in terms of what areas should be diagnosed for a problem. There are three major areas you should investigate, and all three should be checked each time, even if you think the problem is obvious: the control, the wiring, and the lamp or lamps being controlled.

Troubleshooting PLC Lighting Controls

A common problem with PLC controls is that the device coding for one or more control modules is incorrect. Each PLC device is identified to the system with a unique unit code that is typically set using one or two dials located on the device. Figure 25-1 illustrates the unit coding dials on a PLC control module. Most PLC devices have both a house code and a unit code. In larger homes, each zone can be coded to a different house code, with each unit within the zone numbered serially.


Figure 25-1: The unit code dials on a PLC control device

Another common problem with PLC systems can be the phase of the electrical current on the AC lines. The electrical phase, especially if different electrical phases are present on a home’s wiring, can cause problems for lighting control systems that use PLC to communicate with controlled switches/devices. If some devices in a power line lighting control system work and others don’t, the nonworking devices could be on a different phase of the house wiring from those connected to the control unit that serves the signal.

Another common problem with power line systems is that voltage spikes on the AC lines can independently trigger modules. If this is a common occurrence in a home, a spike suppressor or phase filter should be installed on each phase at the main electrical panel.

The problem of modules operating independently can also be caused by power dips (short sags in the voltage) or brownouts (longer sags in the voltage). Many power line lamp modules include a local control feature that allows the module to be turned on or off using the switch on the lamp or device connected to it. The local control feature operates by sensing changes in the voltage level, either up or down, and a sag or spike can cause the module to turn on or off. If this problem occurs frequently, the local control option should be defeated or the modules replaced with modules that don’t have this feature. Of course, another option is to provide backup power at the main electrical panel.

AC Power and Phase Shifts

When the AC power in a home produces two different currents from its main electrical panel, the different currents are said to be in different phases. Several factors can cause phase shifts, such as inductance, reactance, resistance, and so on, but at some point the electrical system is carrying electrical power waves that are identical in every respect, except for their timing.

Figure 25-2 illustrates two electrical currents that are in different phases. Current A and Current B are identical, but Current A peaks and troughs at different times from Current B. If power line devices are on different phases, the receiving station may not properly interpret the command signals transmitted across the AC wiring. The effect is very similar to attenuation on a copper data cable when the signal attempts to move between phases.

click to expand
Figure 25-2: Two AC currents that are out of phase

A cure for phase shifts is the installation of a phase coupler at the electrical panel.

Power line systems are also susceptible to line noise on the AC circuits. Many TV sets generate electrical noise and dump it onto the AC lines. If you suspect that a television or other appliance is affecting the power line control, plug the problem device into a line filter to isolate it from the AC circuits.

Hard-wired intercom systems that transmit over house wiring can block power line signals if they are left in transmit or talk mode. If this problem exists in a home, there are limited possibilities for resolving the issue. Try changing the lighting control system to a different phase of the electrical system or install phase couplers on the electrical panel. However, these changes may not solve the problem. Unfortunately, installing a wireless intercom is not an answer either. For some reason, PLC controllers and wireless intercoms cannot both work in the same house.

Here is a list of things to avoid when using power line controlled switches and control modules:

  • Lamp modulesDon’t use a lamp module to control appliances, fans, fluorescent lamps, any incandescent lamp greater than 300 watts, or any lamp that has a built-in dimmer.
  • Grounded modulesAlways use a grounded module when controlling a grounded device.
  • Wall switch modulesDon’t use a dimmer wall switch module to control fans, appliances, fluorescent lamps, and any lamp less than 60 watts or incandescent lamp with more than 500 watts. Don’t use a dimmer wall switch module to control an outlet into which somebody may plug an appliance, fan, or vacuum cleaner. Relay wall switches are available for controlling these types of loads.

Troubleshooting System Controllers

If a problem develops with the system controller of a lighting control system, in most cases the problem is related to power: The AC power to the enclosure is interrupted, AC power to the controller is interrupted, or the controller’s internal power supply has failed.

  Note

Of course, a problem with a system controller could be related to programming, but every make and model of lighting control systems has fairly unique command sets; there is no way I can really address those issues here. If you suspect a controller problem may lie in its configuration, check the manufacturer’s documentation and your programming setup.

Troubleshooting Load Control Modules

If a relay or dimmer module is failing or performing erratically, check the power source to the module or replace the module itself. However, if you suspect the module is a malfunctioning zone control, check the data line connections and check for continuity and impedance to ensure they conform to the manufacturer’s specifications. Also, verify the ground connection for the main power supply to the enclosure.

Verify the connecting cables between the modules mounted in the lighting control system’s enclosure. If the ambient room temperature where the enclosure is located is warm, make sure the enclosure’s exhaust fan is properly functioning and clean. The modules may be overheating, which may cause them to fail or function intermittently.

Common Lamp Problems

Some problems are common to all lamps. Table 25-3 lists a few of the most common of these problems.

Table 25-3: Common Problems with Lighting System Lamps

Problem

Diagnostic

Resolution

Lamps flickering

How long have the lamps been installed?

A lamp must burn in for around 100 hours before it will produce initial lumens (full light). This includes fluorescent lamps, which should be burned in before dimming.

 

Is the line voltage constant?

Test the line voltage to the lamp and to the lighting control for constant current.

 

Is the HVAC blowing air across the lamp?

Change the direction of airflow away from the lamp, so that the temperature of the lamp remains constant.

Incandescent Lamps

Incandescent lamps are fairly easy to troubleshoot because the problem is typically one of only a few possibilities: the lamp is burned out, the glass bulb of the lamp is cracked or broken, or the lamp is not getting electricity. Table 25-4 lists common problems with incandescent lamps that you should eliminate when troubleshooting a lighting system with this type of lamp.

Table 25-4: Troubleshooting Incandescent Lamps

Problem

Diagnostic

Resolution

No light from lamp

Is the lamp burned out or defective?

Replace lamp.

 

Is the lamp properly seated in its socket?

Remove the lamp and check the socket for good metal-to-metal contact; reseat the lamp.

Short lamp life

Is the voltage supply too high?

Check circuit to correct over voltage situation.

 

Is the lamp subject to vibrations or sudden jarring?

Replace with compact fluorescent or rough-duty lamp.

Lamp bulb has deposits

Is the lamp cracked?

Check for moisture around the lamp and correct; replace lamp with silicone-coated lamp.

Lamp bulb blistering or bulging

Is the operating temperature too high?

Check the wattage of the lamp and match it to the fixture; replace the lamp.

Lamp in recessed fixture burns out too quickly

Does the lamp conform to manufacturer's recommendations?

Recessed fixtures build up heat; too high a wattage or the wrong type of lamp may cause failure sooner than expected.

Lamps brighten or dim when other fixtures are turned on or off

Is the AC power neutral connection properly wired?

Check the neutral connection in the main electrical panel or any sub panels.

The most common problem with incandescent lamps is burnout. While every bulb has an average life rating, all this means is that half of a batch of lamps last longer than the average and half do not. Table 25-5 lists the average life ratings for common incandescent lamp bulbs.

Table 25-5: Incandescent Lamp Average Life and Lumen Output Ratings

Wattage

Average Life (Hours)

Minimum Lumen Output

100

750

1670

75

750

1150

60

1000

840

40

1500

440

Fluorescent Lamps

Fluorescent lamps and fixtures have more components that can fail. Troubleshooting a fluorescent lamp or fixture is a bit more complicated than it is with an incandescent lamp, as evidenced by the length of Table 25-6. The good news is that there are several common failures, and they are the easiest to resolve. Table 25-6 lists common problems with fluorescent lighting systems.

Table 25-6: Troubleshooting Fluorescent Lamps

Problem

Diagnostic

Resolution

Lamps do not start or start slowly

Are the lamps properly aligned in their sockets?

Reseat the lamps in their sockets.

 

Are the sockets cracked or broken?

Replace the fixture.

 

Is the fixture defective?

Install a good lamp to determine if problem is the lamp or fixture.

 

Is the ballast defective?

Replace the ballast.

Good lamps are not lighting

Is the manual reset on starter pressed?

Press reset button on the starter.

 

Is the starter defective?

Replace the starter.

 

Is the ballast defective?

Replace the ballast.

 

Are the lamp and ballast compatible?

Check the labels of the lamp and ballast and replace the lamp with a compatible lamp.

 

Is the lamp dirty?

Clean the lamps and ballasts.

 

Is the line voltage correct?

Check the line voltage and make necessary repairs.

 

Is the fixture wiring correct?

Compare the wiring against the wiring diagram on the ballast's label and correct as needed.

 

Is the ballast working properly?

Replace the ballast.

Lamp has short life

Is the lamp burned out?

Replace the lamp; some lamps fail earlier than others. If problem continues, check the line voltage.

 

Are the ballast and lamp compatible?

High-output (HO) lamps and very high-output (VHO) ballasts (or vice versa) are not compatible; replace lamp with correct type.

The ballast can often be the cause of a problem in a fluorescent fixture, especially in dimmable fixtures. If the lamps in a problem fixture work in another fixture, then the problem is likely either the ballast or starter, or it’s power-related. If the problem is the ballast, it should be replaced. Table 25-7 lists a few problems specific to a failing ballast.

Table 25-7: Troubleshooting Fluorescent Lamp Ballast Problems

Problem

Diagnostic

Resolution

Ballast cycles continuously

Is the line voltage correct?

Check the line voltage.

 

Are the lamps good?

Replace lamps to isolate the problem as a ballast problem.

 

Is insulation covering part or the entire fixture?

Make sure that the ceiling or wall insulation isn't covering part of the fixture, especially the ballast. Too much heat causes the ballast's thermal protector to cycle.

 

Are fixtures mounted to the ceiling designed for that use?

Some fixtures require air space for cooling purposes. Replace the fixture with one designed for ceiling mounting.

Lamp starts too slowly

Is the ballast a rapid-start or instant-start type?

Replace rapid-start ballast with a compatible instant-start ballast.

Lamp will not start

Is the ambient temperature below 50 degrees Fahrenheit?

Many ballast require a minimum starting temperature of 50 degrees Fahrenheit or higher.

Lamps are noisy

Is the ballast securely mounted?

Check the ballast mounting and other loose fixture components that may be vibrating.

 

Is the sound rating of the ballast appropriate?

Check the sound rating of the ballast and either replace it or mount it remotely to the fixture.

Troubleshooting HID Lighting

High-Intensity Discharge (HID) lighting is a general term used to describe any lamp that uses a gas-filled arc tube that operates at much higher vacuum conditions than those used in fluorescent lamps. HID lamps are named by the type of gas contained in their arc tube, such as metal halide, mercury vapor, and high-pressure sodium lamps.

Troubleshooting an HID lamp is very much like troubleshooting fluorescent lamps. Most of the problems, beyond burned out lamps or failed ballasts, are related to power and grounding issues. HID lamps must be matched to the ballast in use to prevent lamp or ballast failure. Another common problem is the use of the wrong lamp in a fixture. For example, metal halide and high-pressure sodium lamps are physically interchangeable, but cannot be interchanged electrically.

If an HID lamp fails immediately after being installed, check the impedance on the AC line. HID lamps are negative impedance devices and require a current-limiting ballast. HID ballasts provide an HID lamp with three functions: the proper starting voltage, the proper operating voltage, and conditioning the current for a particular type of HID lamp. If an HID lamp is not working properly, the problem is either the lamp or the ballast, or both.

Lighting Control System Maintenance Plans

In order to maintain a lighting control system in top working order, there are certain activities that should be performed as a part of a regular periodic preventive maintenance program. Whether the person performing these activities is you or the customer isn’t as relevant as the fact that they are performed, and performed regularly.

Lamp Disposal

State and federal regulations govern the methods that can be used to dispose of lamps and ballasts removed from a lighting system. Fluorescent and HID lamps contain mercury and ballasts contain polychlorinated biphenyls (PCBs), two potentially hazardous waste materials.

The U.S. Environmental Protection Agency (EPA) controls the disposal of fluorescent and HID lamps under the Resource Conversation and Recovery Act (RCRA), which treats these lamps as hazardous waste. As such, these lamps must be disposed of in hazardous waste landfills or recycled. Under the RCRA, they cannot be dumped in a general solid waste landfill or burned. However, recently some newer, and more expensive, lamps have been designed to meet the requirements of the EPA and can be disposed of as general trash.

Prior to 1979, magnetic ballasts contained PCBs, which are also considered hazardous material. A magnetic ballast has a service life of around 25 years, so many are still in service. Many newer magnetic ballasts are now manufactured without PCBs and are labeled as “No PCBs.” However, without that marking, you must assume the ballast contains PCB and must be handled according to the EPA regulations.


Review

Feedback from the homeowner may be the best way to learn about performance problems on a newly installed lighting control system. Debrief the homeowner to learn if the lighting scenes are still effective; if scheduled lighting scene changes occur when they should; if there is a problem with lighting levels in any room, zone, or on a particular fixture; and if the lamp life on a particular fixture or lighting group is less than it should be.

The maintenance activities of a lighting control system primarily involve ensuring the lighting levels and control desired by the homeowner are maintained. The maintenance activities are: performing preventive maintenance, applying control changes, applying manufacturer upgrades, and performing troubleshooting and diagnostics.

A preventive maintenance plan should be developed and regularly executed for the lighting control system. The purpose of a preventive maintenance plan is to maintain the system in proper working order and to prevent or detect problems before they become major. At minimum, preventive maintenance should be performed on the lighting control system once a year.

A backup should be made of the lighting system controller’s programming each time preventive maintenance is performed. One copy of the backup should be kept at the home and another copy should be stored in the project folder off premises.

The importance of maintaining a maintenance log that records all maintenance activities is not often realized until some point in the future when a problem arises that can be traced back to a maintenance action performed in the past.

Hard-wired lighting controls generally have one of two problems: the switch itself is faulty or a problem has developed with its wiring. Relay switching controls, like those controlling an incandescent lamp, have relatively simple problems (broken toggle switch, no power, or bad wiring) and are generally easy to troubleshoot.

A common problem with PLC controls is that the device coding for one or more control modules is incorrect. Each PLC device is identified to the system with a unique unit code that is typically set using one or two dials located on the device. Another common problem with PLC systems can be the phase of the electrical current on the AC lines.

If a problem develops with the system controller of a lighting control system, in most cases, it’s related to power: the AC power to the enclosure is interrupted, AC power to the controller is interrupted, or the controller’s internal power supply has failed. If a relay or dimmer module is failing or performing erratically, check the power source to the module or replace the module itself.

In order to maintain a lighting control system in top working order, certain activities need to be performed as a part of a regular periodic preventive maintenance program.

Questions

  1. When you are troubleshooting a power line lighting control system, the modules on one electrical circuit are working properly, but the modules on a second electrical circuit work intermittently, if at all. What electrical issue may be causing this problem?

    1. Faulty wall outlet modules
    2. Line noise on all circuits
    3. Different electrical phases on separate circuits
    4. Faulty lamp modules
  2. What record should be maintained for an installed home system?

    1. A detail of installation activities
    2. A log that lists repair actions only
    3. A log that lists maintenance activities only
    4. A log that lists all maintenance and repair activities
  3. Which of the following should be included in a comprehensive preventive maintenance program for a lighting control system?

    1. Clean fans
    2. Apply manufacturer upgrades
    3. Verify lighting loads
    4. Identify new or replacement systems now available that could be installed
  4. What action should be taken before beginning any diagnostic or troubleshooting activities?

    1. Retest the system
    2. Disconnect all controls
    3. Debrief homeowner
    4. Apply all manufacturer upgrades
  5. What should be verified or reset when a single PLC control module is not functioning properly?

    1. House code
    2. Unit code
    3. PLC device model number
    4. PLC device serial code
    5. A and B
    6. A and D
  6. What electrical activities on AC lines can independently cause modules to activate on a PLC lighting control system?

    1. Voltage spikes
    2. Voltage sags
    3. Brownouts
    4. Electrical noise
    5. All of the above
  7. If you suspect a zone load control module or zone control is failing, which of the following should you troubleshoot?

    1. The AC power connections to the control
    2. The connections to devices and controls connected to the control module
    3. The data line connections before and after the zone control
    4. Replace the control unit
  8. What is likely the problem when a dimmable fluorescent lamp is exhibiting intermittent problems?

    1. Lamp
    2. Fixture
    3. AC power
    4. Ballast
    5. A or D
    6. A or C
  9. If a problem is isolated to a lighting system controller, what are likely the primary issues?

    1. Power
    2. Data connections
    3. Programming
    4. Revision level
  10. What is the best source of information regarding upgrades and revisions to a lighting system controller?

    1. Trade magazines
    2. Product bulletins
    3. Troubleshooting logs
    4. Manufacturer’s web site

Answers

  1. C. PLC signals can suffer attenuation when attempting to bridge electrical phases.
  2. D. Maintaining a maintenance and repair record of all actions performed on a system can reduce the guesswork when troubleshooting a system.
  3. A, B, and C. When performing maintenance, it may not be the appropriate time to upsell a customer on newer models or systems.
  4. C. If some time has passed since the last maintenance or repair activity, the information the homeowner has about the system’s performance and any needed repairs, corrections, or upgrades can be critical to tracking down any reported problems.
  5. E. Many PLC devices have both a house code and a unit code. Even if the PLC device has only a unit code, it must be assigned uniquely within the system or house.
  6. E. Any abnormal electrical events can cause PLC devices to activate independently or cause PLC command signals to be lost due to attenuation.
  7. A. The first troubleshooting step should be to check the AC power connections and, if a DC transformer is in use, the DC power connections.
  8. E. Problems with fluorescent lamps are typically either the lamp or the ballast. However, when the problem is with a dimmable fluorescent lamp, the first place to begin your troubleshooting is with the ballast.
  9. A. Power is often the contributing factor to a system controller problem.
  10. D. The manufacturer’s web site can provide troubleshooting and upgrade information about a device.






HTI+ Home Technology Integrator & CEDIA Installer I All-In-One Exam Guide
HTI+ Home Technology Integrator & CEDIA Installer I All-In-One Exam Guide
ISBN: 72231327
EAN: N/A
Year: 2003
Pages: 300
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