Carrier 50PQ User Manual
Carrier
Single-Package
y-
Heat Pumps
The number 1
f<x heating & cooling camrr^rcy,
iixJustrial oc eckicational bialdlngsin 5, and 9 ton caf^ities.
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50RQ,PQ
Heating 62,000 to 112,000 Btuh
Cooling 59,000 to 107,000 Btuh
© Carder Ccrpof3t5on 7977
Form 50RQ-3P
The heat pump reverse cycle controls the weather all year round
The Carrier single package heat pump — compact,
efficient, reliable. It puts the weather to work for you
and lowers operating costs.
Thermodynamically, there is no difference be
tween a heat pump and an air conditioning unit or
refrigerator. The heat pump moves heat from a colder
heat source to a warmer heat sink thru the vapor
compression cycle. (The same as a refrigerator or air
conditioner.)
The difference, from a practical standpoint, is in
the heat pump's ability to reverse the roles of the
evaporator and condenser coils.
The heat pump takes advantage of the fact that
even cold winter air contains heat that can be
absorbed for heating a building. During cooling
season operation, the unit can be set to reverse the
evaporator and condenser coils, absorbing heat from
inside the building and discharging it outside — like a
standard air conditioner.
The operating cost advantage of the heat pump
occurs primarily during the heating mode. Depending
on outdoor temperature, the heat pump can actually
produce two to three units of heating energy for
every unit of electrical energy it uses.
The heat pump's cost saving reverse cycle prin
ciple uses refrigerant circulated within a compact,
closed circuit coil to absorb and transfer heat from
one area to another.
The process begins with the evaporator (cooling)
coil absorbing heat from the air around it. The
compressor then pumps the refrigerant to the con
denser where this heat is then rejected to the
surrounding air.
As shown in the diagram, the heat pump makes
double use of the two coils by means of a reversing
valve. The two coils alternate as evaporator or
condenser, depending on whether cooling or heating
is required.
Heating Cycle — Refrigerant enters ^ outdoor coil
(evaporator) at a lower temperature than the surrounding
outdoor air and heat is absorbed by refrigerant. The
refrigerant then passes thru tiie reversing valve and into the
compressor v^/here it is brouÿrt to a nigit temperature and
pressure. The hot refrigerant ieaves the compressor, fiows
thru the reversing valve to the indoor coil (condenser). Heat
is ihert rejected to the return air from the hot refrigerant as
the return air passes over the irxioorcoii (condenser).
Cooling Cycle — The two cotis exchange roles as evaporator
and coftdenser tftry tite action of the reversing valve.
Althougii reversed, system operation is exactly the same.
Refrigerant enters the evaporator (indoor coil) at a lower
temperature than the return air, heat is absorbed from
indoors, the cocker air is then distributed throughout the
building. Refrigerant ieaves the evaporator, flows thru the
reversing vaive and into tha compressor where it is brought
to a higher teinperature and pressure. The hot refrigerant
gas flows from the compressor^-ftiru the reversing valve and
into the outdoor coil (condenser). The outdoor coii (con
denser) rejects the heat from the hot refrigerant to the
cooler outdoor air as it passes over t)te coil The heat
transfer cycle is now ready to be repeated.
JL
A great performer... with unmatched versatility
As the concern for energy grows
and grows, Carrier's 50RQ/PQ
single package heat pump looks
better and better. Short gas supply
and high cost electric power are no
problem with these versatile units
in operation. They're engineered
for a wide range of application . .
and installation is easy. For a
curbed heat pump with plenum, in
one piece ready to swing into place,
there's the 50PQ rooftop Or select
the RQ uncurbed ... on a slab for
horizontal air delivery. Or take the
RQ, attach the accessory plenum at
New and improved features for a lifetime of
II New compressor for heavy duty
service — Carrier's new P compressor
more than meets the rigorous demands of
heat pump operation. Most efficient and
reliable hermetic in Carrier equipment
Thicker crankshaft Bigger bearing jour
nals. Larger valves. Extra large oil pump.
Crankcase heater.
the jobsite and it's a PQ
With an excellent cooling HER,
heating C.O P. among the highest in
industry, factory installed options
and field installed accessories, these
units will match specifications for
the most varied building
requirements
If you're looking for the reliable
one, the efficient one, the flexible
one . . the number 1 heat pump
on the market, LOOK TO
CARRIER!
dependable performance.
'I Signal-LOCTivi _ Carrier's new com
pressor protection system. Holds the
compressor off the line if any operational
or safety device trips the compressor
Operation of any one of the following
devices trips the compressor and lights an
indicator light on thermostat low-
pressure switch, high-pressure switch,
indoor coil freezeup thermostat, internal
line-break overload. Unit can be reset
manually at the thermostat Carrier
Exclusive.
11 Separate System capability (008,010
units) — Individual, independent refrig
eration systems. Operate circuit required
to maintain desired temperature. Provides
for stand-by operation. Less down time,
lowers service costs. Dual compressor
units with 2-stage heating and cooling —
operate with excellent part-load per
formance on heating and cooling. Elec
tric resistance heat is locked out above
40 F. This lowers demand charges and
costs Carrier Exclusive.
II Terminal strip — located in base unit
control box for easy connection to room
thermostat, outdoor thermostat(s),
emergency heat control, economizer and
electric heat
i> Exclusive, innovative variable circuit
refrigeration system — capacity and
COP are among the highest in industry
Maximizes refrigerant to air heat transfer
on both heating and cooling cycles No
other heat pump has it. Carrier Exclusive.
I' Automatic defrost system — Keeps
coil frost-free at temperatures below
40 F. Chrono-temp control activates de
frost system every 90 minutes if required
Automatically deactivates defrost cycle
when coil is clear or after a maximum of
10 minutes. Carrier Exclusive.
SSGNAL-LOC HEAT PUMP PROTECTOR
r—C
UNE8f5EAK
LI-I
L2-
L3-
Accessories and factory installed options
Economizer assembly is available; as s;
factory-installed option or field-installed;
accessory. Located in plenum, it provides;
low-cost cooling on in-between days,’
Automatically controlled dampers open;
to admit cool, filtered outdoor air The:
compressor(s) and outdoor air fan remain;
off to save energy if the outdoor tern-'
perature is low enough to satisfy cooling;
requirements without compressor;
operation. ^
I Remote control panel consists of a sep
"marate heating and cooling thermostat'
assembly plus a decorative wall-mounted '
■i-. rj panel In addition to switches for heating,*
:S|cooling and fan operation, the panel
‘i-^^.icontams 6 indicator lights and, for -
■ 4,1 economizer-equipped units, a ventilation.
] control knob.
Roof Curb with insulated base pans
supports PQ unit (RQ unit with accessory
plenum) and frames roof opening for
plenum and interior ductwork. Once curb
is in place, and ductwork connected, unit
can be placed anytime ~ to meet your
schedule. Curb design meets all National
Roofing Contractors Association (NRCA)
requirements.
Downturn plenum is standard equipmervL, ■
factory-installed on PQ units, field-;
installed accessory on RQ units. Directs ^
airflow downward and provides weather-;
proof openings for ductwork connec
tions. Unit with plenum is curb mounted.;
Thennostat and suUiase (24 V} Acces
sory package provides for selection of
heating, cooling, continuous or automatic
fan cçieratîoR. Works hand-in-fiand with
Signal-LOC circuit. Subbase has v^ming îîÿit (LK-OUT) to automaticaSiy in
dicate compressor lockout condition.
Occupant îs immedîaitely avrare if com
pressor is inoperative Sue to malfunction.
Emergency beat control — Accessory
emergency heat subbase and relay aliow
occupant to manually switch compressor
off and electric heat on if warning light
indicates system rnaifunction. Can be
used for quick morning warm-up or to
merely lock out compressor.
Electric resistance heaters — Available as
factory-installed option or for field in
stallation Complete with high temper
ature limit switches and overcurrent pro
tection. Qffered in 4 heating capacities
for each unit. Where heaters are factory
I installed, unit electrical input is single-
;j point at a factory-supplied terminal
J block. Connection point is suitable for
I copper or aluminum wire (except for
i200-v, 3-phase unit with 1.5 1 electric
:1 heat ratio which uses copper only).
Time Guard® circuit protects compressore
against thermostat "jiggling," automati-f
cally prevents compressor from restarting-;:
for at least 5 minutes after a shutdown.
Accessory prevents short cycling of com-:-;
pressor if thermostat is rapidly changec;
(field installed)
i Motormaster® Head Pressure Control —
i Units are designed to operate at outdoor ,
i temperatures down to 35 F on cooling;
I mode Below 35 F, accessory 32LT ;
I Motormaster control modulates outdoor;
! fan motor to maintain correct condensing >
1 temperature at outdoor temperatures;
down to -20 F.
^Alternate motor ;tnt( drive, a factory-
installed cation, provides extra perform
ance for instaiiaiioos requiring hi^sr
hors^jower die standard motor has
to offer.
Outdoor tfoemtostat($) — Used to lock
out electric heat above certain outdoor
temperature for economical operation.
Fietd-instaiied with wide range of adjust
ments availabie to suit building design
requirements.
hysical data
UNIT 50RQ,PQ
OPERATING WEIGHT (lb)
Unit 50RQ (no plenum)
Unit 50PQ (plenum)
With Economizer
Roof Curb
006
460
590
620
175
008 010
765
925
955
225
825
1005
1035
225
No. ...Type 1 ,6P
Capacity Steps (%)
0, 100
REFRIGERANT R-22
Charge (lbs) Sys 1, Sys 2
OUTDOOR COIL
Total Face Area (sq ft)
OUTDOOR AIR FAN
Nominal Cfm
No. ...Diam (in.)
Motor Hp...Kw
INDOOR COIL
Total Face Area (sq ft)
9 2, -
2-Row, Copper Tube, 15 Aluminum Plate Fins/in
11.7
ropeller Type, Direct Drive
4000
1. 22 1 .26
Уг ..0.8
4 0
P
Copper Tube, 15 Aluminum Plate
Rows 4
INDOOR AIR FAN
One, Centrifugal Adjustable Belt Drive
Size (in.) 10x9
Nominal Cfm 2000
Rpm Range
Std 920-1300 690- 980
Alt
1070-1460
Max Allowable Rpm 1600
Fan Pulley Pitch Diam (in.)
Center Line Distance (in.)
Motor Hp (See note)
Max Bhp
INDOOR AIR FILTERS (50DP) TYPE
No. ...Size (in.)*
*Paciory inS'alled in plenum Dnii: 50RQ,PQ008 will accept 2-in thick filters, field supplied
NOTE: Nominal rpm for 50RQ,PQ006,008 is 3450; for 50RQ.PQ010 Is 1725
Std 9 0
Alt
9 0
15V4
Std
Alt
Std
Alt
1 18
1.69
2 20x25x1
%
1
1 0% efficient, Disposable Fibe
2...6P
0, 50, 100
R-22
6 4, 7 0
17.0
7000
1.1
6 56
12x11
3000
805-1093 800-1090
1500
12
12
1678
1
IV2
1 69
2.11
2 20x25x1
2...16x25x1
Fins/in.
.1--. .1. 4
____________
" Glass
2. P
0, 60, 100
R-22
10 5, 8 0
22 5
7000
1. 26
1.. 1.35
8 5
12x11
3600
690- 980
1500
6
6
1678
iVa
2
2 5
TJ
2 20x25x2
2 16x25x2
Typical piping and wiring
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