Table 143 Problems and solutions the heating ventilating and airconditioning system

Component

Problem

Initial Maintenance Action

Filter Damper

Ductwork

Grillwork Fan

Pump Blower

Chiller

Cooling tower

Compressor Thermostat

Excessively dirty

Blocked open or linkage disconnected Leaks badly Open joints

Loose insulation in duct work Water leakage or rust spots Crushed

Air flow impossible due to dirt Blocked by equipment Motor not hooked up to fan Excess noise Insufficient ventilation Belt too tight or too loose Pulleys misaligned Hot-water pump is cold

(or vice versa) Not moving air in acceptable quantities Excessive noise Rotation wrong direction Shaft does not turn freely by hand Leaks

Scaling on spray nozzles Leaks

Cold water too warm Excessive water drift

Temperature reading not accurate Leaks water or oil from mounting

Replace or clean Check damper controls Clean and overhaul Repair

Replace and attach firmly

Repair

Replace

Remove and clean

Remove equipment

Disconnect motor or install fan belts

Check bearings, belt tension mountings, dirty blades

Check fan and surrounding duct work and grill work

Adjust motor mount

Correct alignment

Inspect valving; check direction of flow

Check direction of rotation and change wiring if needed;

clean if dirty Check bearings, coupler Check wiring Check lubricant; repair Repair

Remove by chipping or by chemical means Repair

Check pumps, fans, and fill; clean louvers and fill

Check drift elimination, metering orifices, and basins (for leaks); check for overpumping See Table 14.7 Calibrate

Check pneumatic control lines to a modern computer-controlled network. The amount of troubleshooting that you can do will be directly proportional to your knowledge of the system. If you know a lot about it, you may be able to accomplish a great deal, even initially. If your knowledge is limited, get advice from someone who has installed such systems, obtain all the operating manuals that pertain to your system, and get estimates of the cost needed to bring your control system up to its designed operation. You can save larger amounts of money by simply adjusting controls—for example, by using a lower temperature on weekends and when no one is in the facility—than you can by any other comparable expense of effort. It pays to get your control system in operating condition and to keep it that way.

Electrical System

Many industrial electrical distribution systems are being used in ways not foreseen by the designers. These changes in use can cause some problems in energy consumption and in safety. If a motor is operating at a lower voltage than it was designed for, it is probably using more amperage than was intended and is causing unnecessary losses in transmission lines. If the wires are too small for the load, line losses can be large, and fire hazards increase significantly. Other problems that can create unnecessary energy loss are voltage imbalance in three-phase motors and leaks from voltage sources to ground.1 Most of these problems are safety hazards as well as expensive in energy costs, and it is imperative that they be checked.

It is desirable to have a qualified electrician or electrical contractor examine your facility to find safety problems. At the same time, a load survey should be performed to determine whether your wiring, transformers, and switch gear are appropriately sized for the load they are currently carrying. To supplement this formal examination, Table 14.4 gives a list of trouble indicators you should look for as you are ascertaining the current condition of your facility. This list should be used in conjunction with the formal survey.

Another problem that may be costing money is a low power factor. The power factor is the ratio between the resistive component of ac power and the total (resistive and inductive) supplied. Because it costs more to provide electricity with a low power factor, it is common for electrical utilities to make an additional charge if the power factor is less than some value, typically 75%. If your electrical bill includes a charge for a low power factor, it may be worthwhile to have a power-factor meter installed and to focus management attention on the problem of increasing the power factor. Equipment that contributes to a low power factor includes welding machines, induction motors, power transformers, electric arc furnaces, and fluorescent light ballasts. A low power factor can be corrected with the installation of capacitors or with a separate power supply for machinery causing the problem. The maintenance of this equipment then becomes another item on the list of scheduled energy management maintenance. Power-factor management is covered in Chapter 11.

Lights, Windows, and Reflective Surfaces

Maintenance of the lighting adjacent to reflective walls, ceilings, and floors serves several purposes in energy management. The energy consumed by lights is significant, as is the energy used by the heating, ventilating, and air-conditioning system to remove the heat put into a building by the lights. But the psychological value may have a greater impact. If lights are conspicuously absent from corridors and, where not needed, from management offices, people tend to look upon energy conservation as a program that is being taken seriously, and they begin to take it more seriously themselves. Similarly, a plant where energy management has been encouraged but where no attention has been paid to lighting is often seen as a plant where energy management is not taken seriously. (For a more complete discussion of lighting, see Chapter 13.)

Many factors modify the effectiveness of the lighting system. Of particular importance are the condition of the lights, the cleanliness of the luminaires, and the cleanliness of the walls, ceiling, and floors. When determining the condition of this system, a light meter should be carried as standard equipment. This will show the rooms where the IES (Illuminating Engineering Society) or other lighting standards have been exceeded or where not enough light is present. There may also be some additional problems, which are described in Table 14.5. Windows can also be a source of light. If they are used this way in your facility, they should be cleaned. If they are not used as a light source, consider boarding them up to avoid having to remove the heat that they allow in from the sun. The lighting systems in a facility are important, both in energy cost and as a morale factor. They deserve your attention.

Hot-Water Distribution System

Hot water can have several uses within a facility. It can be used for sterilization, for industrial cleaning, as a source of process heat, or for washing hands. The maintenance principles for all of these uses are the same, but the temperatures that must be maintained may differ. The purpose of energy systems maintenance in this area is to keep the temperatures as low as possible, to prevent leaks, to keep insulation in repair, and to keep heat-transfer surfaces clean. To put this into perspective,

Table 14.4 Problems and solutions: the electrical system.

Component

Problem

Initial Maintenance Action

Transformer

Leaking oil

Have electric company check at once

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