42Sma Furred-In Mega Units - Carrier 42S Series Instruction Manual

prevent sweating and must be protected from wear or erosion at
the joint between the insulation and the fireproofing material.
When no risers are ordered for the universal stack unit, it is the re-
sponsibility of the installer to make sure that an isolation ball valve
is installed between each supply and return piping connection to
the unit. Flare fittings are factory provided to allow connection be-
tween the ball valves and the hoses.
Supply Air Installation
Each side of the unit has one supply air knockout as well as a sup-
ply air knockout on the top of the unit (see Fig. 20).
1. Determine which supply air opening/openings are required
for your application.
NOTE: The supply air opening on the riser side of the unit should
not be used.
2. Use a sharp retractable knife to trim insulation using center
knockout slot/trim line as pattern (see Fig. 27).
3. Use a sharp standard needle nose pliers and grab knockout
tab (see Fig. 27).
Fig. 27 — 42SUA Unit Supply Air Knockout Tab
Location
4. Twist or pry pliers back and forth until knockout tab breaks
away from unit.
5. Repeat for all supply air tabs until all have been broken.
6. Discard center knockout piece. Be careful of sharp edges.
7. Use a sharp retractable knife to trim any excess insulation
using knockout hole as pattern.
8. Use duct pliers (hand seamers) to fold duct flange out of the
unit 90 degrees for each side of the supply air opening along
duct break (see Fig. 27). The 90-degree flanges can now be
used as drywall stops to prevent coverage of discharge open-
ing (see Fig. 28).
90°
Fig. 28 — 42SUA Supply Air Installation
9. Use adhesive or glue to re-attach insulation that has pulled
away from the unit during knockout removal process.
10. For ducted applications tape should be applied along and
around all of the supply air opening knockouts to prevent air
leakage.
Knockout Tab
(10 Places)
Duct Break
(4 Places)
Knockout Tab
Trim Line
Duct Flange
Unit Wall
Unit
Installation
All installations should be made in compliance with all governing
codes and ordinances. Compliance with all codes is the responsi-
bility of the installing contractor.

42SMA FURRED-IN MEGA UNITS

The unique design of the mega stack fan coil unit allows for field-
configuration of each unit. Risers, shown with unit, are for refer-
ence only. All risers are factory-fabricated and shipped loose for
field installation. It is important that you identify all of the unit
feature locations before proceeding with the installation (see
Fig. 11).
Unit orientation is determined based on the location of the risers in
the building. Risers can only be installed on the rear side of the
unit and always determine the rear of the mega stack unit. The re-
turn air is always on the front (see Fig. 29).
LEFT
R D S
R = RETURN
D = DRAIN
S = SUPPLY
2- or 4-PIPE
Fig. 29 — 42SM Unit Installation
Supply, Return, and Drain Risers
Toxic residues and loose particles resulting from manufactur-
ing and field piping techniques such as joint compounds, sol-
dering flux, and metal shavings may be present in the unit and
the piping system. Special consideration must be given to sys-
tem cleanliness when connecting to solar, domestic or potable
water systems. Coil not rated for portable use.
NOTE: Submittals and product literature detailing unit operation,
controls, and connections should be thoroughly reviewed
BEFORE beginning the connection and testing of risers and
piping.
The supply and return connections are marked on the coil stubouts
and the valve package depending on your configuration. "CS"
means cold water supply, "CR" means cold water return, "HS"
means hot water supply, and "HR" means hot water return to indi-
cate flow direction to and from the coil. Blue letters mark the
chilled water connections and red letters mark the hot water con-
nections.
The unit internal piping is designed to accommodate a total riser
vertical movement of ±1-1/2 in., due to thermal expansion and/or
contraction, when positioned properly at the jobsite. Risers must
be anchored to the building structure to limit riser expansion and
contraction movement to a maximum of 3 inches. Riser anchoring
and expansion compensation is not included in the factory-sup-
plied unit and must be field-provided. While some special riser
features are available from the factory, riser end caps, air vents,
and/or flushing loops are normally provided on the job by the
installer.
22
HR HS D CR CS
REAR
42SMA 14-20
RIGHT
CABINET
FRONT
RETURN AIR
HR HS CR CS
D
HR = HOT WATER RETURN
HS = HOT WATER SUPPLY
D = DRAIN
CR = COLD WATER RETURN
CS = COLD WATER SUPPLY
CAUTION