Carrier 50ME User Manual
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Hot Water/Glycol Heating 160,000 to'800,000 Btuh
Eiectric Cooling 180,000 to 360,000 Btuh
Electric Heating 180,000 to 540,000 Btuh
Gas Heating 480,000 to 720,000 Btuh
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0 ® Commercial buildings
:© Carrier Corporation 1982
Form 48MA/50ME-3P
No hot decks. . .no cold decks. . . no zoning dampers. . .no energy waste!
It’s what you don’t get with Carrier’s
Zone-Mizer Modular Multizone unit
that sets it apart from all the others.
You don’t get hot decks or cold decks
because the Carrier design gives each
zone module its own cooling coil and
heating section. Each zone module
operates independently. One unit can
heat, cool, dehumidify, reheat, and
ventilate up to 12 different zones simul
taneously. All this means real energy
savings. . .there’s no wasteful duplica
tion of effort as in hot deck/cold deck
units. For still more energy savings,
Zone-Mizer provides up to 3 steps of
electric heat or gas heat with an inter
mittent pilot ignition in every zone.
Something else you don’t get. . .
zoning dampers. Since the Carrier de
sign doesn’t have hot and cold decks, it
doesn’t need zoning dampers. By elimi
nating them from the picture, you
eliminate the adjustments, service, and
operating problems that go along with
zoning dampers.
Five sizes, offering capacities to 37
tons, provide equipment flexibility and
economy. One large unit may serve
where 2 units were required before; or
units of different sizes may be mix/
matched to deliver the heating/cooling
capacity required in a specific applica
tion. And the choice of gas, elecfric or
hot water/glycol coils allows you to
select a unit that can deliver maximurn
operating economy and convenience by
taking advantage of an already available
heating plant or favorable area fuel
rates.
1 Etched solid copper circuit
panels have interchangeable plug-in
relays to minimize parts stocking Cir
cuit breakers that may be used as dis
connect switches, terminal boards to
simplify installation of accessories, a
control circuit shutoff switch and 24volt controls are all standard.
Motorized outdoor air inlet
damper — A simple rheostat adjust
ment on the unit (or on the optional re
mote control panel) sets the damper to
control the amount of outdoor air
admitted.
5 Dependable cooling — Each ser
viceable hermetic compressor system
has cylinder unloaders for capacity con
trol and electric power savings. Crank
case heaters, accumulators, filter driers
and low-ambient starting controls are
also standard.
Time Guard® electrical circuit pre
vents rapid cycling of the compressor if
occupant tampers with the thermostat.
Compressor cannot short-cycle on a
safety device, such as the low-pressure
switch, should someone forget to clean
the air filters.
Capacity control permits a wide oper
ating range. During light loads the com
pressor automatically unloads to re
duce operating costs and maintain
steady compressor operation. When
the load drops below the minimum
unloader stage, the hot gas bypass con
trol provides continuous cooling
operation.
Built-in safety controls prevent
damage to unit components. Included
are high- and low-pressure switches,
overtemperature limit switches and
overload protection for all motors.
When specifying a multizone unit,
choose the one that makes a point of
doing something about installation
problems. . .the Carrier Zone-Mizer
Modular Multizone. It’s a sturdy, onepiece unit — factory-wired, piped, and
charged. It arrives ready to be set in
place on the specially designed roof
curb. Make the power and control con
nections and that’s it. Initial adjust
ments are trouble free — you won’t
even need a factory engineer at start
up. The total package carries the UL
label or is design certified by AGA.
DG
3 Fused 115-volt convenience out
let in the control box provides power at
the unit for work lights and small power
tools.
4 Motormaster® solid-state con
denser fan speed control permits
year-round operation of refrigeration
system down to -20 F ambient.
6 Polyurethane foam sandwich
access panels are of Weather Armor
galvanneal steel. Their thermal resis
tance prevents sweating at outdoor
conditions up to 77 F dew point And
they are strong enough to support a
250-pound man.
/ Rugged extruded aluminum
frames and protective grilles provide
strength and good looks. Unit will not
sag during rigging.
Low silhouette — The cabinet has no
vents or hoods to break up the clean
appearance. The curb-mounted unit
seldom requires a parapet to hide it
from street level view.
<5 Humidry® coil — This separate
cooling coil dehumidifies the outdoor air
before it is mixed with the return air to
prevent high indoor relative humidities
in humid weather and during partial
load operation.
‘ 5 Large filter area — Over 41 square
feet of standard filter area is factory
supplied. Filter tracks will accept
one-in. or 2-in., high- or low-velocity,
permanent or throwaway, standard or
high-efficiency filters.
10 Electric heater section (SOME)
— Each zone module has its own 2- or
3-stage electric heater assembly or hot
water/glycol heating coil. Electric
heaters have 24-volt relays and 115-volt
contactors. Each heating element has
circuit breakers and automatic thermal
reset. Each leg has its own heat limiter
(fusible link).
Each hot water/glycol heating coil
has its own solenoid operated shutoff
valve and balancing valve. All heating
coils are prepiped to supply and return
manifolds which also include a bleed
valve.
Gas heating (48MA) — Each zone
module has stainless steel burners,
Porcelon™ heat exchangers and its
own redundant gas valve. Natural gas
units also have a regulator for each
gas valve. Intermittent pilot ignition
and forced draft combustion are
standard on all units.
Zonc-Mizer^” Modular Multizone concept. How it works. . .
Outdoor air enterirvg the unit thru the
side louvers is filtered and then cooled
and dehumidified by the Humidry®
cooling coil when mechanical cooling is
operating. Return air entering the unit
from below is mixed with this condi
tioned air The mixture is then filtered.
After passing thru the indoor air fans,
the air is discharged into the individual
zone modules. The air passing thru
each zone module is either cooled or
heated in response to a signal from the
thermostat controlling that module.
This treated air then continues to the
individual zone duct systems, thus pro
viding a constant air pattern and volume
on each cooling coil and heating
assembly
Each zone module cooling coil has its
own solenoid valve to admit refrigerant
when needed. When 2 or more mod
ules are grouped for a larger zone re
t
quirement, 2-stage cooling can be
provided. . .and controlled by one
simple 24-volt mercury bulb thermostat
This condenser end view of unit (034
and 040) shows the 3 outdoor air fans
and the side condenser air inlet grilles.
The 2 end panels may be easily removed
for control box and compressor
accessibility.
SPLITS AIRSTREAM INTO ZONES
ADDS ADDS DIRECTS HEATED
SEPARATE OR SEPARATE OR COOLED AIR
COOLING HEATING TO INTERIOR ZONES
and why it’s best.
Low operating costs
On partial load, the Carrier compres
sors unload cylinders to match com
pressor output to cooling needed with
up to 6 steps of reduction. To maintain
balanced operation, the hot gas bypass
system diverts hot refrigerant to the
outdoor air cooling coil as needed.
There is no mixing of warm and cold
airstreams in the modular design. Just
that amount of energy required to heat
or cool a given zone is used — and no
more.
Heating is available 3 ways. . .
Electric heating, provided by 2- or
3-stage electric heaters in each module,
gives up to 36 steps of capacity, again
using the minimum amount of energy.
Hot water/glycol heat may be speci
fied to utilize an already available
heating plant.
Gas heating models utilize inter
mittent pilot ignition in each module
designed to consume a minimum
amount of energy.
Low»temperature operating capa
bility. . .You can use the economizer
cycle with outdoor air for “free cooling,”
as with competing units. However, with
Carrier’s head pressure controlled re
frigeration system, you can often save
money by using refrigeration to cool
the space instead. So-called “free
cooling” is expensive if a large quantity
of cool outdoor air must be heated for
the zones which do not require cooling.
The Carrier refrigeration system can
operate at outdoor temperatures down
to -20 F. The Carrier modular design,
therefore, is not dependent on an
economizer cycle for cooling at low
outdoor temperatures.
Superior humidity control
One of the major concerns in multizone
applications has been the control of
humidity, especially in schools where
moisture comes from large groups of
people as well as from outdoor venti
lation air. The basic Carrier design elim
inates this problem. During mechanical
cooling, all outdoor air that passes thru
the Humidry® outdoor air cooling coil
is dehumidified whenever any zones
require cooling. The air is then further
dehumidified when it passes thru the
zone module cooling coil.
If further dehumidification should be
required for any or all zones, reheat can
be added easily. A humidistat, installed
in the conditioned space to override the
thermostat, energizes the cooling coil
for that zone.
Ease of service
The Zone-Mizer™ Modular Multizone
uses simple, familiar, commercial, ther
mostatic controls for each module,
eliminating the need for factory experts
and complex start-up and service
procedures. The printed control circuit
board has clearly marked terminals for
easy connection of standard 2-stage
heating and one- or 2-stage cooling
thermostats, which are located in
each zone.
Identical relays plug into the circuit
board. Modules can be easily combined
to serve larger spaces by placing
factory-supplied jumper wires on the
premarked terminals.
The entire control system is neatly
organized in one location. For excellent
accessibility, all circuit breakers project
outside so that any motor can be dis
connected without opening the highvoltage box. This often eliminates
the need for separate field-supplied
disconnects.
The handsome Carrier mercury bulb
type thermostats control heating and
cooling modes. They are available with
a locking device which requires an Allen
wrench for access, or you can allow
the zone occupant to set his own
temperature.
Access to the Zone-Mizer Modular
Multizone is thru removable side panels
held in place with simple fasteners. Top
panels may also be removed for com
plete access to unit interior.
In short, the local installing dealer or
contractor can handle all service and
will have available, from the nearest
Carrier distributor, any parts required.
Accessories and factoryii'stalled options
Hot water/glycol heating (SOME) —
Often, such as when renovating existing
buildings, a heating plant is available.
For these applications, Carrier’s hot
water/glycol heating unit may be ideally
suited Each zone module has its own
high-capacity heating coil All controls,
solenoid operated shutoff valves and
balancing valves are included. No
internal piping or wiring required.
Heaters are designed for and in
tended to be operated with a glycol/
water solution of 20% minimum glycol
concentration for freeze-up protection.
(Factory-Installed Option).
Roof curb supports unit and frames
roof openings to provide a strong,
watertight interface between unit and
roof. Galvanized, 14-gage steel, 2-piece
construction minimizes installation time
and costs. (Accessory)
Modulating outdoor air control pro
vides year-round ventilation with out
door air. An outdoor air thermostat
locks out compressors to permit “free
cooling” with outdoor air. (FactoryInstalled Option)
Roll filter package includes 65 ft of
2-in. thick filter media, automatic media
advance switch and a motor. The run
out switch turns on the filter light in the
remote control center to show when the
media needs replacing (FactoryInstalled Option)
Powered exhaust damper has con
trols to operate outdoor air fans to
exhaust return air when unit is in “free
cooling” mode. (Factory-Installed
Option)
Cooling only unit (SOME) — Unit is
available with all heating controls but
without heater assemblies. Included are
24-volt control circuits and 115-volt
power terminals for 2-stage control of
steam heating coils field installed in the
unit or in the zone ductwork.
t
Electric heat (SOME) — Each zone
module is equipped with its own inde
pendent heater assembly. Two- and
3-stage heat is available to provide close
air temperature control without wide
temperature swings associated with
rapid-cycle, full-on, full-off systems.
Three heat-to-cool ratios are avail
able: .75.1, 1.1 and 1.5:1 to match
almost any heating load requirement.
(Factory-Installed Option)
Zone thermostat (24 volts) provides 2-stage heating
and one- or 2-stage cooling for control of individual
modules. Matching subbases are available with or with
out tamperproof switches and automatic changeover.
(Accessory)
Remote control panel (24 volts) — This decorative
central control for the entire unit has switches for HEAT,
COOL, AUTOMATIC CHANGEOVER, OFF and
DAY/NIGHT settings; dial to adjust outdoor air damper
to rapidly ventilate conditioned spaces. A dirty filter
warning light and knockouts for additional warning lights
are also provided. (Accessory)
*hysiccd data
UNIT 48MA/50ME
Zone Modules
Nominal Cooling Capacity (tons) 15
OPERATING WEIGHT Tib)
Base Unit 48MA 3385
Base Unit SOME (with heat) 2985
Roof Curb 506
REFRIG CHARGE (lb, R-22) 28
COMPRESSOR
No. 1 Type
Cylinders. Unloaders 6 2
No. 2 Type
Cylinders (has no unloaders)
System Oil Charge (pts)
Unloader Settings (psig)
Left Bank
Right Bank
Capacity Steps (%) 100,67,33
OUTDOOR AIR FANS
Motor Hp .Rpm...Frame (NEMA)
Nominal Cfm
INDOOR AIR FANS
No. ...Size (in.)
Cfm (Nom) 6000
Motor Hp .Rpm
Fan Pulley
Outside Diameter (in )
Bore (in.)
Fan Belt No ..Size w/Std Mtr
Motor Pulley A
OutsideDiam(in.) w/Std Mtr
Bore (in.) 1-1/8
Resulting Fan Rpm w/Std Mtr 880
Motor Pulley B
Outside Diam (in.) w/Std Mtr 60
Resulting Fan Rpm w/Std Mtr
OUTDOOR AIR COOLING COIL
Face Area (sq ft)
Corrugated Fins/in ...Rows
EVAPORATOR COILS (zone)
No. ...Face Area (sq ft, ea)
Corrugated Fins/in .Rows
HEATING SECTION (48MA)
Rise Range
Input (1000 Btuh) Total
Bonnet Cap (1000 Btuh) Total
HEATING SECTION (SOME Electric)
Electric Heaters
No . .Elements (ea)
fiiMTNG SECWON (ici/ii*GTvcoii
Max Allowable Inlet Temp
Max Allowable Flow, Each Coil
Solution Mixture
Max Allowable Working Pressure
Total Internal Volume (gallons)
PRESSURE SWITCHES
Low-Pressure
High-Pressure
Indoor Airflow Switch (AFS 1
Factory Setting (cfm)
Adjustment Range (cfm)
INDOOR AIR FILTERS
Std No. ..Size (in )
High Efficiency (optional)
m
No. . Size (in )
Roll Media (optional)
OUTDOOR AIR FILTERS
No . Size (in )
No 1
No. 2
No 3
w/Opt Mtr
w/Opt Mtr
w/Opt Mtr
w/Opt Mtr
w/Opt Mtr
Each Module
Full Rate
Cutout
Cut-in
Cutout
Cut-in
016 024
8
06DE537
—
—
.... " .
— — —
16,500 15,000
2 15x15 2 15x15
5 1725
10 6
1-3/16 1-3/16
1 3V630 1 3V630
—
5 3
— — — —
—
—
995
—
68
13 2
8. .2 12
13 3
432
54
324
40 5
8 2 or 3
2 61
■ or 3-Stage, Nichrome, Open-Wire Flesistance Elements in Each Zone Module
8 10 10 12
20 25
3805
3405
506
32 43
06DE824
6.2 6 ..2
06DA824
6
22
100,83,67
50,33,17
8000 10,000 10,000
7-1/2 1725 10 1725 10 1725 15 1725
10 6 80 80
60 50 50
1-3/8 1-3/8 1-3/8 1-5/8 1-5/8
995
— —
69
— —
1145
—
Thermostatic Expansion Valve, Hot Gas Bypass
68
13 2
8. .2 12
13 3
432
54
324
40 5 40 5 40 5 40 5
8 2or3 J_ 10 2 or 3 I 10 2 or 3 [ 12 2 or 3 |
2 61
6000
4000-600
Same but with 36 5% efficiency (NBS Dust Spot Test)
2 20 X 25 X 1
028 030 034 040
4075
3665
506
Reciprocating Hermetic. 1725 Rpm
06DE537
06DA824 06DA537 06DA537
6 6
22 22 21
Compressor No 1 Only
71 0 ± 1 5
57 5 ±25
760 ± 1 5
62 5 ±25
100,80,60
40,20
Propeller, Direct Drive
1 1075 56(1-phase)
1 1140 56 (3-phase)
15,000
Centrifugal; Belt Drive
2 15x15 2.15x15 3..15x9 3. .15 X 9
1-3/16
2 3V560
—
Factory Installed
1095
Shipped With Unit
56
1230 1230 1230 1230
—
6 8
1
13 2 13 2 i
Solenoid Valve and Capillary Tube for each
I 10.212 I 10.212 I
Furnace Assembly in Each Zone Module
25 F to 55 F at 0 75 in wg ESP
540
54
405
One Heating Coil in Each Zone Module
3 15 3 15 3 76 3 76
65 ft of 2-in media
6 8
I
13 3 j 13 3
200 F
6 Gpm
20% Glycol
30 Psig
29 + 5 Psig
39 ± 5 Psig
400 ± 5 Psig
300 ± 5 Psig
12 20 x 25 x2
28 30
4080
3670 4400 5250
506
43
06DE537
6.2
100,80,60
40,20
-
15,000
1-3/16
2 3V560
—
1095
—
5 6 5 6
—
—
I
540
54
405
4800
630
57 66 1
06DE537 06EE250
6.2
6
75 5 ± 1 5
58 0 ± 2 5
100,83,67
50,33,17
1.1140 56 (3-phase)
24,000
12,000
20 1725
8.0
1-11/16 1-11/16
2 3V630 2 3V630
3 3V670
50
6.0
1095
1320
6 5
1425
102
13 2
12.201
12 3
648
54
486
9000
6000-9000
2 32 X 35 X 1
12
37
5700
630
4.1
06EA250
4
31
—
100,75,
50,25
23,000
12,000
15 1725
20 1725
80
3 3V670
50
6.0
1095
1320
56
6 5
1425
102
13 3
12.201
15 3
648
54
486
40 5
12 2or3
Roof curb dimensions (48MA)
COMPRESSOR, CONDENSER
AND CONTROL BOX END '
OF UNIT
Certified dimension drawings available on request.
UNIT
48MA 1
016,024,028,030
034,040 i
A 1 B
]B- 2% Î 7-3
21-1 r/j 1 7-ll-y<
48MA0M. 040 02 ZONE)
ZONE MODULE END
CURB DETAIL
I c
1 D
i n-9
Î 14-iy
DiMENSiONS (ft-in.)
i........E
.5-6 V,
6-7’/,,
......
i 7-2%
i 8-4%,
MAIN GAS l3 FPT CONN
ON SASE UNIT
evaporator (ZONE MODULE ¡AIRFLOW
* NOT USED ON 48MA0t6,024(8 ZONE
NOTES- I FOR additional INFORMATION SEE
; F
Î 1-10%,
Î 2- 9% j 3-1
module UNITS)
BASE UNIT PH.YSICAL DATA AND
DIMENSIONS
2 MAXIMUM ALLOWABLE UNIT PITCH IS
jlN IN lOFT IN ANY DIRECTION
3 REMOVE SHIPPING BRACE BEFORE
ASSEMBLING CURS SECTION
(LOCATION SHOWN).
i G
i H
1 2-2%, I 6-0%
! 6-8% i 0-10%,
'6'.4|"4SMA028,
'030 (10 ZONE MODULES)
5'-r 48MA016, 024
(8 ZONE MODULES)
1 J
1 C- 7%
Base unit dimensions (48MA)
Certified diiTiension drawings avaiiabie on request
UNIT
m
48MA
016,024,
028,030
034,040
*Ovsra!i height: induces 1 3/4-in for fan guards WSMA034 an.d 040
i A
1 7- 21^
1 7-n
lJ
_______
i B I c
f
----------------
I 3-0%
1
“T
-----------------
i
; 21 - 9%«
; 0
1 2-2*%s
1 4-2
DIMENSIONS (ft-
1 !3-5%
i i3-5%
!
1 0- 9^6
in.)
1 G
i 2-10
i 3- 4%s
1 ”
1 7-3%« r /«
I 8-6% 1 0-3
i ■)
0-3%
K
L
0-3%
0-7%
Base unit dimensions (SOME)
BASE UNfT SOME
CONO£NS£R AIR INLET
^ GRILLES ON UNITS
034,040 UNIT POWER
SUPPLY 24" KO
IN BOTTOM OF UN!T
CONTROL SOX
(EXCLUDES HEATERS)
034, 040
t
• CONDENSER AIRFLOW
notes: I SPACE REQUiRED FOR SERVICE
AND AIR FLOW ALL AROUND
AND ABOVE UNIT IS 36 iN.
2 FOR ADDITIONAL INFORMATION
SEE ACCESSORY ROOF CURS
DIMENSIONS.
3 CENTER OF gravity IS WITHIN
6IN RADIUS OF GEOMETRIC
CENTER OF UNIT
4 MAXIMUM allowable PITCH OF
UNIT IS -¿-IN. IN lOFT IN ANY
DIRECTION.
UNIT
SOME
016,024.028.030
034,040
^■Overaü r.eigdt, inciudes ' 3/4 in fc* fan guajds .(oOV-ЕОЗА and 0^0).
A
7- 2%
7-1 i
i ®
: 3-0^«
i 3-9”/.** 21- 9Мб i 4-2% ! 13-54 i
DIMENSIONS (ft-in.)
j 2-2^5<* 1 13-54 i
10
c i D . j E i
ELECTRIC RESISTANCE
HEATERS MAIN POWER
_
_______
G
ELECTRIC resistance
CONN. 4|" KO
: Я
i 0-2‘4б
T| heaters main POWER
Certifiées dimensior> drawir^gs avaueble ori request.
F
3-74* i 7-34* i 0-34
4-4 г 8-64
i J
i 0-34
i 0-74
Roof curb dimensions (SOME)
COMPSeSSOR, CONDENSER
AND CONTROL SOX END
OF UNIT
Certified dimension drawings available on request
--------------------------—J
------------
UNIT 1
48MA A
016,024,028,030 1 IS- 2%
034,040 j 2i-n%
ELECTRIC resistance
HEATER POWER
Ag'KO ON UNIT
) GLYCOL CONN
-10Й SUPPLY’
I г"РРТ ON UNIT
DIMENSIONS {ft-in
В {
7- 3 !
n-9
i D i E i F
c
i S-6% 1 7-2% 1
7-11% : ;4-l% i 6-7%« i 8-4%« j
11
5' 50ME0I6.024
ЮЙ' SUPPLY GLYCOL CONN
2"PPT ON UNIT
if) evaporator (ZONE module; AIRP'lOW
* not used on 5CWE0I6,024(820NE
NOTES- 1 POR ADDITIONAL INFORMATION SEE
module UNITS)
BASE UNIT PHYSICAL DATA AND
DIMENSIONS
Z MAXIMUM ALLOWABLE UNIT PITCH IS
■jlN IN ЮРТ IN ANY DIRECTION.
3. REMOVE SHIPPING BRACE BEFORE
ASSEMBLING CURB SECTION
(LOCATION SHOV/N)
)
i G
i H
1-10%« i 6-0%
2- 9%
iilL
i 6-8%
030 OOZONE
MODULES)
¡8 ZONE
MODULES)
] J
I 0- 7%
i 0-10%«
Selection procedure (with example)
Refer to Carrier’s Engineering Guide for Multizone Unit
Systems and contents of this booklet for typical multizone
design considerations. Using the Engineering Guide, cal
culate cooling and heating load estimates for the areas to
be served by the multizone unit. Divide each area into zones
based on the peak load and control requirements within
the area.
The resulting loads calculated for a typical building are;
Cooling
Grand Total Load (GTL)
........................................
272,440 Btuh
Sensible Load (SL) .................................................. 219,000 Btuh
Room Design .................................................... 75 F db/50% Rh
Outdoor Air (OA) Cfm............................................................1000
OA Ambient Temperature
..............................
95 F db/75 F wb
Electric Power Source...................................................... 460/3/60
Zone No. (RTL)/Zone (RSL)/Zone
1 19,000 Btuh 16,935 Btuh
2 25,000 Btuh 22,505 Btuh
3 25,000 Btuh 22,505 Btuh
4 70,000 Btuh 59,160 Btuh
5 22,000 Btuh 19,720 Btuh
6 25,000 Btuh 22,505 Btuh
7 40,000 Btuh 33,870 Btuh
Total 226,000 Btuh 197,200 Btuh
*Loads are peak loads
Room Total Load* Room Sensible Load
Heating (Electric Resistance Heat required)
Zone No. Heating Load/Zone Electric Resistance/Zone
1 34,000 Btuh 10 0 kw
2 44,000 Btuh 12 9 kw
3 44,000 Btuh 12 9 kw
4 111,000 Btuh 32 5 kw
5 42,000 Btuh 12.3 kw
6 44,000 Btuh 12 9 kw
7 81,000 Btuh 23 7 kw
Total* 400,000 Btuh 117 2 kw
*Zone Peak Capacities
Selection:
Base the multizone unit selection on cooling load require
ments. Enter the 48MA/50ME rating tables in the Per
formance Data Section and select the unit that meets or
exceeds the grand total load at the specified conditions.
(Interpolation may be necessary to obtain unit rating at
certain conditions; extrapolations are not advised. Contact
Carrier Application Engineering tor performance data at
points beyond the range of published tables.) Tbe 024 size
unit does not have sufficient capacity to meet load
requirements at any cfm. The 028 size exceeds load require
ments; however, it is the smallest unit that meets specifica
tions. Thus, the 48MA/50ME028at: 9000 cfm; 1000 cfm OA;
95 F/75 OA temperature; and 75 F/50% Rh room design has
a Total Capacity (TC) of 282,000 Btuh, Sensible Heat Ca
pacity (SHC) of 219,000 Btuh and a compressor kw of 27.5.
Calculate the Room Total Capacity (RTC) and the Room
Sensible Heat Capacity (RSHC) by deducting the outdoor
air load from the unit capacity. The outdoor air load with
respect to room conditions is:
Total Heat (OATH) = 4.5 (hoa - hroom) (OA cfm)
= 4.5 (38.61 - 28.29) (1000)
= 46,440 Btuh
Sensible Heat (OASH)
- 1.09 (toa - troom) (OA cfm)
= 1.09 (95 - 75) (1000)
= 21,800 Btuh
The unit capacity available to offset room loads is:
RoomTC = UnitTC - Outdoor Air TC
= 282,000 - 46,440
= 235,560 Btuh
Room SHC = Unit SHC - Outdoor Air Sensible Heat
= 219,000 - 21,800
= 197,200 Btuh
For comparison.
Actual Load
GTL = 272,440 Btuh
SL = 219,000 Btuh
RTL = 226,000 Btuh
RSL = 197,200 Btuh
Actual Unit Capacity
TC = 282,000 Btuh
SHC = 219,000 Btuh
RTC = 235,560 Btuh
RSHC = 197,200 Btuh
The 48MA/50ME size meets or exceeds the total and zone
load requirements at the specified conditions. The excess
RTC decreases space average relative humidity slightly
below the room design of 50%. By increasing air quantity
above 9000 cfm, this excess latent capacity can be
converted to additional sensible capacity if desired.
Since the modular multizone is a constant volume
machine, proportion the selected supply cfm per zone to
satisfy each zone’s peak load condition.
Divide room sensible capacities (RSC) equally among
the modules if an equal cfm is going to each. In this
example, the 48MA/50ME028 has 10 modules and the
nominal cfm is 900 cfm per module and equal cfm’s are not
going to each.
Vary the cfm to each zone (with field-supplied manual
dampers in zone ducts) to match different zone require
ments. Since the original rating was based on 9000 cfm
supply air, all variations must total 9000 cfm. When the cfm
is changed (by some percent) from the nominal in a specific
module, use the room capacity multipliers in the Zone
Cooling Capacity Multiplier Table to correct room TC and
room SHC for that zone. Capacity versus cfm changes for
the example is given in the Capacity vs Cfm Change
table.
By analyzing each zone’s ratio of deviation from equal
sensible heat allocation, determine the proper cfm change.
In the example, if building room SHC is 197,200 Btuh and
10 zones are used, each zone’s normal room SHC is
19,720 Btuh. But if Zone 3 has 22,505 Btuh room SHC, then
by ratio of 22,505: 19,720 or 1.14, the cfm change is +20%.
Correspondingly, if Zone 1 had 16,935 Btuh room SHC,
the cfm change is -20%.
In applications where the zone selection is not an incre
ment of the number of unit modules (i.e. one zone requiring
500 cfm in a 48MA/50ME028 with 10,000 cfm), refer to
Module Cfm Limits (page 36), Application Data section for
details on using cfm’s below 600 cfm/module.
Formulas required to use ratings are:
Outdoor Air Total Heat (OATH)
OATH = 4.5 (OA cfm) (hoa - hroom)
12
CAPACITY VS CFM CHANGES
ZONE
NO.
NO. OF RSL/ZONE
MODULES
...
1
2
3 1
4
5
6
7
RSHC — Room Sensible Heat Capacity RSL —
10 197,200
PEAK LOAD (RSL/NOM UNIT RSHC) FROM NOMINAL UNIT RTC
1 16,935
1 22,505 22,505/19,720
3 59,160
1
1 22,505
2 33,870
22,505
19,720
22,505/19,720
59,160/3 X 19,720 =
22,505/19,720 1 .14 : +20 1080 1 11
33,870/2 X 19,720 =
% DEVIATION
16,935/19,720
19,720/19,720
.86*
1.14
1 .14
1 00
1.00
86
Room Sensible Load
ZONE COOLING CAPACITY MULTIPLIERS
%
CFM CHANGE*
+ 35
+ 20
+ 10
0
-10
-20
-35
*Must not be greater than 1200 cfm nor less than 600 cfm per module,
tlf resulting RSHC is greater than RTC, then RSHC equals RTC
ROOM TOTAL
CAPACITY
(RTC)
1.15
1.10
1.05
1.00
0 95
0 90
0 85
ROOM SENSIBLE
HEAT CAPACITY
(RSHC)
1.14t
1 07t
1.00
0 93
0.86
0.79
Outdoor Air Sensible Heat (OASH)
OASH = 1.09 (OA cfm) (toa - troom)
Room Total Capacity (RTC)
RTC = Unit TC - OATH
Room Sensible Heat Capacity (RSHC)
RSHC = Unit SHC - OASH
Leaving Air Temperature (LAT)
TAT + + RSHC
LAT = room temperature - ^ Q'^f^
Determine Heating Capacity:
The specified requirement for electric heat dictates the
selection of a 50ME028 unit with a kw option that meets
or exceeds the heating load.
The Electric Resistance Heater Data table (page 30) indi
cates that the 028 unit has heating capacity options of 66,
88 and 132 kw. The 132 kw option is selected as it provides
adequate heat for this application. The kw/zone and
number of heat stages available are:
Zone No. Load
1
2
3
4
5
6
7
Total
10.0
12 9 kw
12 9 kw
32 5
12 3 kw 13.2 kw
12 9
23 7
117 2 kw 132 0 kw
Zone Heating
Capacity
kw
kw
kw
kw 26.4 kw 6
13 2 kw 3
13 2 kw 3
13 2 kw 3
39 6 kw 9
31 2 kw
Stages
of Heat
3
3
30
% CFM CHANGE
-20 720 i 9
+20
+20 1080 1 11
0
0 900 ! 1 .0
-20 1440 1 .9
Stages of heat are controlled individually in the small zones
or collectively in large zones to provide flexible and
continuous control for each zone.
Determine fan requirements
For 48MA/50ME operation, cfm range per module is 600
to 1200 cfm. Lower flow volumes are permissible if only
first stage of heat is operated. Volumes above 1200 cfm
may cause water blow-off during cooling.
Since the various unit zones operate at different air
quantities and different external resistances, identify the
zone having the highest static pressure requirement for
the supply duct and supply outlet.
Usually, the longest duct run to the last outlet, with the
greatest number of offsets and elbows, has the greatest
static pressure requirement. Assume a duct friction analysis
has been made and the cfm and static pressure are:
Zone No. CFM
The total unit (02810or 030) cfm is 9000. Zones 4 and 7 have
3 and 2 modules, respectively, “ganged” together to comply
with the limitation of 1200 cfm per module
The cfm for Zone 2 is 1080 with an ESP of 0.8 in. wg. This
module appears to possess the highest friction loss. There
fore, the main fan static pressure is established at 8 in. wg
ESP.
Enter Fan Performance table at 9000 cfm, .8 in. wg ESP
and read: 1020 rpm and 5.4 bhp. The 028 indoor fan motor
data shows the standard 10 hp motor with a maximum bhp
of 11.5. Therefore, 5 4 bhp for this selection is satisfactory.
In the Physical Data table, 2 pulley selections are available
with the 028: Pulley A, shipped mounted; Pulley B, shipped
in the blower compartment. Pulley A has a fixed pitch and
at 1095 rpm is close enough to the required cfm and should
be used. Pulley B at 1230 rpm allows selection of the unit
at higher cfm’s and static pressures.
13
jUNIT TOTAL
CFM3 CAPACITY
Imultiplier
1080
1
11
2700 i 1 0
9000 j
RTC — Room Total Capacity
ESP (in. wg)
1
2 1080
3 1080
4 2700
5
6
7
Totals 9000
720
900
1080
1440
UNIT
NOMINAL
RTC/ZONE
X
23,556
X
23,556
X
23,556
X
3 X 23,556
X
23,556
X
23,556
X
2 X 23,556
No. Modules CFM/Module
6
8
5
6
4
4
5
1
1
1
3
1
1
2
ADJUSTED
21,200
25,912
25,912
70,668
23,556
25,912
42,400
235,560
720
1080
1080
900
900
1080
720
Performance data
Room Design 75 F/50% Rh
OUTDOOR
R
Db
Wb
85
90
95
100
105
no
115
OUTDOOR
TEMP
Db Wb
65 204
85
70 204
65
70
90
73
75
65
70
95
75
78
80
70
100
75
78
70
105
75
110
78 183 133
115 75
0 750
TC SHC Kw
65
168
70
168 J18
65 164
70
164
73
164 116
75 164 116
65
I6U
70
160 114
75
160 114 16 0 173 121 16 6
78
160 114 16 0 175
80
160 114
70
156 112
75
156
78
156 112 16 5 171
70 152
75
152 no 17.0
78
148
75
144 107 18 0
TC SHC Kw TC
200 141
200 141
200 141
200 141
196 140
196 140
196
196
196 140
192 137
192
192 137
187 1 35 20 9
187
178 131 22 3 191 155 23 3 200
14 8 174
118
14.8
116 15 4 169
116 15 4 173
15 4 176
15 4
114
16 b
16 0 169 126 16 4
16.0
16 5"^
112 16 5 168 123 17 2
no 17 0 160 130 17 5
109
17 5
0
143
18 0
143
18.0
18 8 208 155 19 2
18 8
18 8
18 8
19 5 203 157
19 5
140 19 5 212
140 19 5
19 5
20 2
137 20 2 207 150 21 2 216
20 2 209 147
135 20 9 201
21 6
4,000
Outdoor Air Cfm
TC SHC Kw
126 15 1
178 122
177
165 131
177 116
164
164
161 124
155
Outdoor Air Cfm
212
217
212
215
216 146
207
214
216
202
197
199 150 22 8
15.3 184
129
15 7 172
124
15 9 179 131
121 16 0
119 16 1
16 2
118 16 8 186
16 9
128 17 0
120 17.4
125 17 8 172
18 5 171 139 19 1 154
130
18 8 162 152
5,000
750
SHC Kw
153 18 5 216 161 18 7
149
18 7
151 19 5 219
148 19 6
19 7 227
19 9
153
20 2
148 20 5 222 154
145 20 6
143 20 8 230
155 20 9 209
21 4 221 154
157 21 6 204
152
21 9 211 166
1500
TC
177 134 15 2
183 125
186 121
168
174 137 16 7
182 127 17 1 167
189
170 143
177 133 17 7 163 124
181 127 18 0 163 124 16 9
165 149 17 9
TC SHC
224
212 167
224 152 20 1 210 159
208 173 20 2 206 157
214
227
210 166 23 6
Kw
SHC
15 6
124
15 8
140
16 2
16 4
16 5
146 16 4
17 4
121
116 17 5 167
17 3
139 18 3 158 123 17 4
19 4
1500
Kw
19 1 215 161
152
19 4 210 159 19 3
158 19 9 210 159
148 20 3 210
164
20 6
21 1
148 21 4
144
21 6
170 21 3 201
160
21 8
22 1
176
22 1
22 6
24 0 186 149
178
0
TC
SHC Kw
130
176
176
130
171
128 15 8
171
128 15 8
171
128
171
128
167 126
167 126
126
167 126
126
163 124
158 123 17 4
121
149 119
0
TC
SHC Kw
215 161
206
206
206
206
201
201
196
196
191
18 6 222
18 6
19 3
19 3
159 19 3
20 1
157 20 1
157
20 1 220 1 66 21 0 229
157 20 1
157 20 1
155 20 8 211 172 21 5
155 20 8 214
155
20 8 217
153
21 5
153 21 5
151
22 2 206 168 23 3
22 9
COOLING CAPACITIES
TOTAL UNIT CFM
5,000
Outdoor Air Cfm
750
SHC K w TC SHC
TC
15 2
181 139 15 4 184 146 15 6 181 142 15 4 186
15.2 184 134
176
179 136 16 2
15 8 182 133
15 8
183
16 3
172
16 3
175 138 16 8
16 3
178 133 16 9 186 139
16 3
180 130 17 1
16 3
182 128 17 2
16 9
170
16 9
173 136 17 5
175 132 17 6
165 143 17 9
168 138 18 1 175 152 18 5
17 9 166 137
18 4
159
TOTAL UNIT CFM
Outdoor Air Cfm
TC
226 167 19 2
218
221 169 20 0 227 176
223
225
213
216
222 163 21 1
224
205
209
TW 173" 23 8 206
15 6 190 137 15 9
141
16 0 179 152 16 2 176 140 16 0
16 3
131
16 4 191 133 16 8 176
143 16 6 174 158 16 7
141
17 3
18 7 - - -
142 19 1
6,500
750
SHC Kw
171
19"0 226
173 19 8
166
20 1
164
20 2 234 166
175 20 5
171
20 7 222 182
160
21 2 236 162 21 9 212 174 20 5
21 7
168
164 21 9
174
22 2 212 193
169
22 4 217 184
1500 0
Kw TC SHC Kw
181 142
185 143
188
180 149 17 0
190 133 17 6
175 155 17 6
181
170 162 18 2
TC SHC Kw TC SHC Kw
233 170 19 5 222 178 19 0
222 Tss 2b"b 2i7 i76" T9" 7
231
217
233
217
223
227 172
215 184 24 0 197
16 4 176 140 16 0
137 16 6
- -
146 17 9 167
- - -
- -
1500
179
170
191
172 21 5 212 174 20 5
166
188
178
T95" TTT" 191
176
140 16 0
140
172
138
172
138
172
17 4
-
_
19 2
20 3
20 6
20 7
20 8
21 1
21 7
21 8
22 2
22 5
22 6
23 0 202 169 21 9
138
172
138 16 6 184
172
138
167 136
136
167 136 17 2
162 134
162 134 17 7
158 132 is 2 T69
153 130 18 7
222
178
217 176
217 176
217 176 19 7
212 174
212 174
212 174 20 5
207
172 21 2 216'
207
172 21 2 220
207 172 21 2
202
169 21 9
167 22 6
f65 23"3 202
15.4
16 0
16 6
16 6
16 6
16 6
\17 l74
17 2
T7T T69 154^
Outdoor A r Cfm
0
19 0"
229"
232
224
19 7 227
19 7 229
231
20 5 219
20 5
222 187
225
228 179
229 177
222 181 22 2
"2ll
214
210
48MA/50ME016
6,000
Outdoor Air Cfm
750
TC SHC
189 146 15 8 194
181
184
186
187
176
179 150
182
185
177
179 144 17 8
172
162 153‘
Kw
150 15 7
152 ibb 183 1641
148
145
143
155
145 17.1 189
142 17 2
140
152
147
149 18 3
T48
TC
188
16 4
189 155
16 5
192 149
16 6
194
178 170
16.8
183
17.0
17 3
17 5
178 '167
17 7
'18‘T 17l3 173
TF9
19 3
48MA/50ME024
8,000
750
TC
Kw
SHC
i 88"
183
l"90"
185
182
181
191 20 9
182 21 3 233 189
189"
184 22 0 227
19T
186 22 8
185 23 6
T89
TC
19 4
233" 196 19""6
19 5
239 187 19 9
20 1
228 202
20 3 233
20 4
237 187 20 8
20 5 239
223 207
21 1 227
21 4
21 5 - -
21 8 222
22 5"
"21 7 210"
221
24 1
1500
SHC
T58^
149
145
161
151
_
_
- -
__ _
- -
-
1500
SHC
20 4"
193 20 6
183 21 0
21 2
199 21 4
21 8
_
_
204
22 2
195 22 5
- - 22 9
201 23 3
_ _ _
- -
Kw
15^8'
26 1
T6^4'
16.6
16 8
16 9
T7V0
17 2
17 5
T7 8
18 4
kw
_
t
AIR
TFMP
Db
85
95 75
100
lO*'
no
lis
0
Wb
TC SHC Kw
65
265
70
65
70
73 259
75 259
65 254
70
78
80
70 248 182
75
78
70
75 242
78
75
190 24 6
265
190
259
188 24 9
259 188 24 9 274
188 24 9 277
188
185
254
185
254
185
254
185 25 8
254
185 25 8 279
248 182 26 7 266
248 182
242
180 27 6
180 27 6 259 201
236
177
230 174
—
24 0
24 9 279
25 8
25 8
25 8
26 7 261 205 27 6
26.7
28 4
29 2
7,000
Outdoor Air Cfm
1000
TC
SHC Kw
203
275
280 197
269
206
200 25 8 282
196 25 9
193 26 1
262
208 26 4
267
202 26 7
273 196
276
192
189 27.3 294
198 27 9 277 212
269 194
254
207 28 4 261
256
199
246
206
2000 0
Kw
TC
24 6
24 8 289
25 5 273
27 0 284
27 2 290 196
28.1 283
28 8 270 220 29 5 252
29 9 268 219
30 4 256 236 31 2
SHC
280 213
201 25 3 277
221 25 7 271
209 26 2 271
287
201 26 5 271 210
291 196
267 229
275 217
204 27 7 264
190 28 3
268 225
203
233
TC
24 8
277
271
26 7
264
26 6
264
27 1
264
28 0
264
258
28 0
28 6 258
29.0
258
252 202
28 9
245 199
30 8
239
TOTAL UNIT CFM
9,000
Outdoor A ir Cfm
1000 2000
SHC Kw
213 24 6
213 24 6
210
210 25 6
210
ToT 26 5
208 26 5
208
208 26 5
208
205 27 4
205
205
202
197
TC SHC K w
287 226 25 2
291 220
25 6 280 229 26 1 284 244
284
25 6 287 219 26 5
25 6
289
273
277 225 27 3 284
26 5
282
285
26.5 287 212 27.8
270 228
27 4
275 221 28 5 284 235 29 1
27.4
277 217 28.6
28 3 263 230 29 0
28 3 267
29 1
263
29 9
253
25 4
223
26 3 291
216 26 6
27 0 277
231
219 27 5
214
27 7 297 219 28 4
28 2
224 29 3 276
222
30 4 - -
229 31 0 262
14
— — —
TC
SHC
291 236
298 224 25 8 285 234
296 225 27 0 278 232 26 0
299 219 27 2 278 232
292 227 28 1
276
- - -
269 255 29 5
25 4
26 3 278 232 26 0
232 26 7 278
252 27 2
240 27 7
-
-
248
28 6
243 30 0 258 223
258 31 7
—
0
Kw TC
SHC
285 234
232
272 229 26 9
272 229 26 9
272 229 26 9
272 229 26 9
272
229 26.9 292
265 226 27 8 276
265 226
226
265
258 223 28.7 269
-
221 29 6
251
245 218 30 3
Kw
25 1 294
25 1
26 0 291
26.0 295
27 8
27 8
28 7 273
48MA/50ME028
11,000
Outdoor Air Cfm
1000
TC
298 242 25 8
287
293 241 26 9
280
284
288
291
280 243
283 239
268 243
258 250 31 4
SHC
25 6
248
"26 5
"250"
244 26 7
27 0
238
27 4
252
27 7
247
27 9
240
236 28 1
233 28 2
249 28 6
28 8
29 0
"29 5
252
29 7
245
30 8
Kw
2000
TC
SHC Kw
"298 "258 25 s'
305 246 26 1
"266 26 '7
297 254
302
304 241
"283
290
282 "269
274 274
27 1
246
27 3
27 5
273 27 6
262 28 0
28 9
29 8
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