Cooling/Heating System; Direct Expansion (Dx) Systems; Air System Balancing; Water System Balancing - Carrier 42S Series Instruction Manual

COOLING/HEATING SYSTEM

Prior to the water system start-up and balancing, the chilled/hot
water systems should be flushed to clean out dirt and debris which
may have collected in the piping during construction. During this
procedure, the system should be flushed from the supply riser to
the return riser through a cross-over loop at the end of the riser col-
umn, and all unit service valves must be in the closed position.
This prevents foreign matter from entering the unit and clogging
the valves and metering devices. Strainers should be installed in
the piping mains to prevent this material from entering the units
during normal operation.
During system filling, air venting from the unit is accomplished by
the use of the standard, manual air vent fitting, or the optional, au-
tomatic air vent fitting installed on the coil. Venting can be accom-
plished by depressing the needle valve core. 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
operations. See Fig. 42 and 43.
Manual Air Vent
Fig. 42 — Manual Air Vent
Automatic Air Vent
Fig. 43 — Automatic Air Vent
CAUTION
The air vent provided on the unit is not intended to replace the
main system air vents and may not release air trapped in other
parts of the system. Inspect the entire system for potential air
traps and vent those areas as required, independently. In addi-
tion, some systems may require repeated venting over a period
of time to properly eliminate air from the system.

Direct Expansion (DX) Systems

NOTE: Operation of DX equipped fan coils at any fan speed other
than high fan speed is not approved and will void the manufactur-
er's limited warranty.
IMPORTANT: Do not operate fan coils with a DX evaporator
coil plus contiguous hydronic coil without use of a suitable
glycol solution that is approved for use by the manufacturer.
Failure to follow this instruction will void the manufacturer's
limited warranty.
IMPORTANT: Should the evaporator freeze due to inadequate
airflow for any reason, damage may occur to adjacent water or
steam coil tubing. This type of issue is due to product misappli-
cation and voids the manufacturer's limited warranty.

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 balancing operations. Refer to Table 2.
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 procedures 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 bal-
ancing other than selecting the desired fan speed. Units furnished
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 de-
livery and the actual fan motor amperage draw for each unit
should be recorded in a convenient place for future reference.
Table 2 — Maximum External Static Pressures
42SG/SJ/SH
Max at High Speed
Max at High Speed
Max at High Speed
42SMA
Max at High Speed
Max at High Speed
Max at High Speed

Water System Balancing

A complete knowledge of the hydronic system, along with its
components and controls, is essential to proper water system bal-
ancing. This procedure should not be attempted by unqualified
personnel. The system must be complete, and all components
must be in operating condition BEFORE beginning water system
balancing operations.
Each hydronic system has different operating characteristics de-
pending 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 appropriate
system operating conditions such as various water temperatures
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 noticeable
water noise or undesired valve operation. After the entire system is
balanced, these conditions will not exist on properly designed
systems.

Water Treatment

Proper water treatment is a specialized industry. Carrier recom-
mends consulting an expert in this field to analyze the water for
compliance with the water quality parameters listed below, and to
specify the appropriate water treatment regimen. The expert may
recommend typical additives such as rust inhibitors, scaling pre-
ventative, antimicrobial growth agents, or algae preventatives.
Anti-freeze solutions may also be used to lower the freezing point.
Carrier water coil tubes and headers are constructed of pure cop-
per. Multiple brass alloys may be present in the valve package, de-
pending on unit configuration. It is the user's responsibility to en-
sure the tube and piping materials furnished by Carrier, are com-
patible with the treated water. Refer to Table 3 for water quality
parameters.
IMPORTANT: Failure to provide proper water quality may af-
fect the fan coil unit's warranty.
29
ESP
0.40
0.30
0.20
ESP
0.60
0.40
0.25