Carrier 50PQ User Manual

Carrier			Jiy
		4.	50RQ,PQ
Single-Package	y-	¿^ ! '0	Heating 62,000 to 112,000 Btuh
			Cooling 59,000 to 107,000 Btuh
		I
Heat Pumps		I V

The number 1

f<x heating & cooling camrr^rcy,

iixJustrial oceckicational bialdlngs-

in 5, and 9 ton caf^ities.

© 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.

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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

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	m o s t v a r i e d b u i l d i n g

requirements

If you're looking for the reliable one, the efficient one, the flexible one . . the number 1 heat pump on the m a r k e t , LOOK TO C A R R I E R !

New and improved features for a lifetime of dependable performance.

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.

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.

'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 lowpressure 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

SSGNAL-LOC HEAT PUMP PROTECTOR

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UNE8f5EAK

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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.		^

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.;

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.

^Alternate motor ;tnt( drive, a factoryinstalled cation, provides extra perform­ ance for instaiiaiioos requiring hi^sr hors^jower die standard motor has to offer.

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^m- ing 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.

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.

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 >

1temperature at outdoor temperatures; down to -20 F.

hysical data

UNIT 50RQ,PQ			006	008			010
OPERATING WEIGHT (lb)
Unit 50RQ (no plenum)			460	765			825
Unit 50PQ (plenum)			590	925			1005
With Economizer			620	955			1035
Roof Curb			175	225			225
No. ...Type			1 ,6P		2...6P			2. P
Capacity Steps (%)			0, 100		0, 50, 100			0, 60, 100
REFRIGERANT			R-22		R-22			R-22
Charge (lbs) Sys 1, Sys 2			9 2, -		6 4, 7 0			10 5, 8 0
OUTDOOR COIL			2-Row, Copper Tube, 15 Aluminum Plate Fins/in
Total Face Area (sq ft)			11.7		17.0		22 5
OUTDOOR AIR FAN				P ropeller Type, Direct Drive
Nominal Cfm			4000		7000			7000
No. ...Diam (in.)			1. 22		1 .26			1. 26
Motor Hp...Kw			Уг ..0.8		1.1			1.. 1.35
INDOOR COIL					Copper Tube, 15 Aluminum Plate			Fins/in.
Total Face Area (sq ft)			4 0		6 56		8 5
Rows			4		.1--. .1. 4
INDOOR AIR FAN				One, Centrifugal Adjustable Belt Drive
Size (in.)			10x9		12x11			12x11
Nominal Cfm	Std		2000		3000			3600
Rpm Range			920-1300		690980			690980
Max Allowable Rpm	Alt		1070-1460		805-1093			800-1090
	Std		1600		1500			1500
Fan Pulley Pitch Diam (in.)			9 0		12			6
Center Line Distance (in.)	Alt		9 0		12			6
			15V4		1678			1678
Motor Hp (See note)	Std		%		1			iVa
	Alt		1		IV2			2
Max Bhp	Std		1 18		1 69		2 5
	Alt		1.69		2.11		____________ TJ
INDOOR AIR FILTERS (50DP) TYPE				1 0% efficient, Disposable Fibe			" Glass
No. ...Size (in.)*			2 20x25x1		2 20x25x1			2 20x25x2
					2...16x25x1			2 16x25x2
*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

Typical piping and wiring