Carrier 42C,V Manual de instalación descargar pdf (Pagina 80)

Start-up procedures vary depending on time of year (sum-

mer or winter) and building characteristics (new building/old

building, occupied/unoccupied, etc.)

Start-up in the cooling mode requires that proper care be

given to avoid condensation problems. Condensation forms on

surfaces that are colder than the dew point of the surrounding

air. If a unit is started and is piped with low-temperature chilled

water in a hot, humid atmosphere, condensation will form on

many parts of the unit. In order to avoid excessive condensa-

tion, higher temperature water should initially be used (approx-

imately 65 to 70 F) and the fan coil control set at low or medi-

um fan speed. Be sure the fan current does not exceed motor

nameplate values. Also, outside air supply fans, and bathroom

and kitchen exhaust fans should be off.

As the building temperature drops, the chilled water temper-

ature can be gradually reduced until it reaches 50 F. At this

point the outside air fans can be turned on. When the chilled

water temperature is reduced to its design point, the exhaust

fans can be turned on.

Cooling/Heating System — Prior to the water system

start-up and balancing, flush the chilled / hot water systems to

clean out dirt and debris which may have collected in the pip-

ing during construction. During the process, all unit service

valves must be in the closed position to prevent foreign matter

from entering the unit and clogging the valves and metering de-

vices. Strainers should be installed in the piping mains to pre-

vent such material from entering units during normal opera-

tion.

During system filling, air venting from the unit is accom-

plished by the use of standard manual air vent or optional auto-

matic air venting installed on the coil. Manual air vents are ba-

sically Schrader valves. For air venting, depress the valve unit

the air has vented the coil. When water begins to escape

through the valve, release the valve. Automatic air vents may

be unscrewed one turn counterclockwise to speed initial vent-

ing but should be screwed in for automatic venting after start-

up operation. See Fig. 100 and 101.

Air System Balancing — All duct stubs, grilles, filters,

and return-access panels must be properly installed to establish

actual system operating conditions BEFORE beginning air bal-

ancing operations.

Each individual unit and the attached ductwork is a unique

system with its own operating characteristics. For this reason,

air balancing is normally done by balance specialists who are

familiar with all procedures required to properly establish air

distribution and fan-system operating conditions. These proce-

dures should not be attempted by unqualified personnel.

Units with no ductwork have air volumes predetermined at

the factory by supply grille size and normally do not require air

balancing other than selecting the desired fan speed. Units fur-

nished with optional dampers on supply grilles may require

some small adjustments to “fine tune” the air delivery to each

grille. Opposed blade balancing dampers are not available for

all grilles on a unit with electric heat.

After proper system operation is established, the actual unit

air delivery and the actual fan motor amperage draw for each

unit should be recorded in a convenient place for future refer-

ence.

Water System Balancing — A complete knowledge

of the hydronic system, along with its components and con-

trols, is essential to proper water system balancing. This proce-

dure should not be attempted by unqualified personnel. The

system must be complete, and all components must be in oper-

ating condition BEFORE beginning water system balancing

operations.

Each hydronic system has different operating characteristics

depending on the devices and controls used in the system. The

actual balancing technique may vary from one system to

another.

After the proper system operation is established, the appro-

priate system operating conditions such as various water tem-

peratures and flow rates should be recorded in a convenient

place for future reference.

Before and during water system balancing, conditions may

exist due to incorrect system pressures which may result in no-

ticeable water noise or undesired valve operation. After the en-

tire system is balanced, these conditions will not exist on prop-

erly designed systems.

Water Treatment — Proper water treatment is a special-

ized industry. Carrier recommends consulting an expert in this

field to analyze the water for compliance with the water quality

parameters listed in Table 8 and to specify the appropriate wa-

ter treatment regimen. The expert may recommend typical ad-

ditives such as rust inhibitors, scaling preventative, antimicro-

bial growth agents or algae preventatives. Anti-freeze solutions

may be used to lower the freezing point.

Carrier’s water coil tubes and headers are constructed of

pure copper. Multiple brass alloys may be present in the valve

package, depending on unit configuration. It is the user's re-

sponsibility to ensure the tube and piping materials furnished

by Carrier are compatible with the treated water.

Failure to provide proper water quality will void the fan

coils unit's warranty.

Table 8 — Water Quality Concentrations

Controls Operation — Before proper control operation

can be verified, all other systems must be operating properly.

The correct water and air temperatures must be present for the

control function being tested. Some controls and features are

designed to not operate under certain conditions. For example,

on a two-pipe cooling/heating system with auxiliary electric

heat, the electric heater cannot be energized with hot water in

the system.

A wide range of controls, electrical options and accessories

may be used with the equipment covered in this manual. Con-

sult the approved unit submittals, order acknowledgements,

Fig. 100 — Manual Air Vent

Fig. 101 — Automatic Air Vent

WATER CONTAINING REQUIRED CONCENTRATION

Sulphate Less than 200 ppm

pH 7.0 to 8.5

Chlorides Less than 200 ppm

Nitrate Less than 100 ppm

Iron Less than 4.5 mg/l

Ammonia Less than 2.0 mg/l

Manganese Less than 0.1 mg/l

Dissolved Solids Less than 1000 mg/l

CaCO3 Hardness 300 to 500 ppm

CaCO3 Alkalinity 300 to 500 ppm

Particulate Quantity Less than 10 ppm

Particulate Size 800 micron max

1 2 ... 75 76 77 78 79 80 81 82 83 84 85 86 87 88

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Carrier 42C,V Manual de instalación Pagina 80

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