Airwell PAC HT Series Engineering Data Manual

Brand: Airwell

Model: PAC HT Series

Category: Heat pumps

Type: Engineering Data Manual

This manual is also suitable for

Airwell PAC HT Series heat pumps are designed to replace traditional hot water boilers for domestic hot water (DHW) production. They can also be used for space heating, with the ability to maintain a high coefficient of performance (COP) even at low outdoor temperatures down to -20°C.

The PAC HT Series features two-stage compressors that provide higher COP and maintain heating capacity in low outdoor temperatures. The use of each compressor stage can be controlled separately, allowing for optimized energy consumption and adaptability to different heating requirements.

The units are equipped with a hydrophilically coated air exchanger to assist condensed water drainage, preventing clogging and reducing the frequency of de-icing operations. Reinforced polypropylene, low-speed fans ensure efficient airflow with minimal sound levels.

Engineering Data Manual

PAC HT

High Temperature Air-to-Water

Heat Pumps

Models 12-6, 14-7 & 18-9

AN AIRWELL GROUP COMPANY

12.0 to 17.9 kW



Dual zone system installation (radiators and under-ﬂoor heating)

Installation examples



Single zone system installation (radiators)

PAC HT

Domestic hot water

(DHW)

tank

Domestic hot water

(DHW) tank

Radiator system

ambience

thermostat

Radiator system

room

thermostat

Low temperature zone

room thermostat (under-

floor heating)

Insulated underground hot water pipes

General Characteristics

Introduction

This new range of PAC HT air/water high temperature heat pumps offers the

special feature of producing hot water at 65 °C at outdoor temperatures down

to -20 °C, while guaranteeing a high COP.

For outdoor temperatures above +7° C, the PAC HT supplies water at 55 °C

with a single compressor.

Consequently, this PAC HT unit is ideally suited to replace a traditional hot

water boiler in producing Domestic Hot Water (DHW).

The patented technology uses two-stage compressors that provide :

➜ Higher COP :

In fact, in a two-stage system, each compressor operates at a low

compression ratio, i.e. 3:1 compared with 12:1 for single-stage

compressor systems.

This improves the compressors' service life and reduces electricity

consumption.

➜

Same heating capacity maintained even with low outdoor temperatures :

As compressor efficiency is maintained, PAC HT performance is hardly

affected, even at low outdoor temperatures.

➜ Remarkable adaptability in terms of matching supplied capacity

to heating requirements thanks to the possibility of using each

compressor stage separately :

The PAC HT controller chooses the optimum compressor staging

configuration according to the demand for heating and the heat emitters'

operating temperatures.

➜ Optimised Domestic Hot Water production :

Both for producing DHW and Heating, the controller determines the

compressor staging best suited to the DHW tank coil's heat exchange

capacity, while taking account of the outdoor temperature. At the end of

the heating phase, the DHW temperature is very close to the condensing

temperature without an unnecessary energy consumption.

Scope of application

The PAC HT is mainly designed as a replacement for the boiler without altering

the rest of the installation.

Bodywork and structure

Steel bodywork coated with oven-baked epoxy paint coating.

The unit base is equipped with large openings under the coil for condensate

or de-icing water drainage.

Removable panels on all sides allow access to the electrical box and to the

refrigeration and hydraulic circuits. Closed bodywork protection index : IP 24.

Compressors

Maintenance-free Scroll type compressors produce a high efficiency with low

sound levels.

The two-stage circuit equipped with 2 compressors with an unrivalled

capacity ensures the best possible matching of supplied capacity to heating

requirements.

Anti-vibration pads under the compressor prevent the transmission of any

vibrations to the bodywork.

Water side exchangers

Brazed plate construction operating on a counter flow configuration in Winter

mode to ensure excellent heating performance.

Air exchanger

Treated with a hydrophilic coating to assist condensed water drainage.

The exchanger is sized to avoid clogging, maintain its performance in sub-

zero temperatures and cut the time and frequency of de-icing operations.

Fans

Reinforced polypropylene, low-speed helicoidal fans with optimised fan blade

profiles to ensure efficient air flow at an extremely low sound level.

Fully-enclosed motor, maintenance-free bearings, automatic reset overheating

protection device. The fan blades are shielded by plastic grilles for personal

protection in accordance with health & safety standards.

Refrigerating circuit

The patented refrigerating circuit enables each compressor to be used

independently or in two-stage mode.

The circuit, factory-filled and tested, includes a filter-dryer, two thermostatic

expansion valves, high and low pressure safety devices and all the equipment

specific to two-stage technology.

Electrical box

The electrical box contains all the components for PAC HT operation and

notably the system's protection devices : compressor protection circuit

breaker or fuse, protection fuse, standard start-up current limiter for single-

phase units, phase sequence controller for three-phase units.

The microprocessor based controller integrated in the box controls all the

PAC HT's functions with the help of a room terminal and temperature sensors.

Safety functions controlled by the controller :

 High and low pressure safety, lack of water flow, lack of refrigerant

charge, low evaporation pressure, high and low outlet water temperature

limits, winter frost protection, compressor short cycling protection.

 Diagnosis of failures with history of 150 latest alarms (code, description,

occurrence time and sensor values at the time of alarm).

Other functions managed by the controller :

 Water temperature control (inlet and outlet) depending on outdoor

temperature and ambient temperature (water law).

 Choice of compressors for optimised efficiency.

 De-icing the outdoor exchanger in winter.

 DHW production management.

 2-stage extra electric heating management.

 Management of boiler relief without additional kit (not compatible with

extra electric heating).

General Characteristics (continued)

Control

Standard equipment

The PAC HT is supplied with the following standard equipment :

 Electrical box including electrical safety devices, circuit breakers, fuses.

 Electronic controller and its keypad screen.

 Communicating room terminal.

 Main disconnect switch.

 Start-up current limiter (depending on models).

 Phase sequence controller (three phase models).

 Refrigeration circuit with its safety devices.

 Hydraulic kit comprising : 3 speed circulation pump, flow controller,

automatic bleed, drain, pressure gauge, safety valve (3.5 bars).

 4 pads for sound insulation under the casing.

 Exchanger protection grille.

 Water filter.

 1 filter stop valve.

Options and accessories

Accessories available for fitting on site :

 Vibration absorbent pads.

 Water valves with pressure tapping.

 Set of hoses – Length 1m, Ø 1 inch.

 3-way directional valve to be used with domestic hot water tank and/or

boiler relief.

 300 litres water tank for Domestic Hot Water production and 2.5 kW

fitted and wired electric heating resistance. 230 V single phase or 400

V three phase. DHW production management and Legionnaires' disease

protection controlled entirely by the PAC HT's standard controller.

 Additional electric heating, independent of the heat pump, to be fitted in

the circuit. Capacity : 6 kW, 2 stages : 2 kW + 4 kW. This option is

available for new installations or boiler replacement only.

 Filter (sludge trap)

 Buffer/Mixing tank, 140 litres.

The water law parameters are programmed in the controller at the factory. It

is possible to adapt them more precisely to the specific features of the home

when the PAC HT is being installed :

 Base outdoor temperature at the site of the home.

 Home heat losses compared against the base temperature for an ambient

temperature of 20° C.

 Inlet water temperature for the corresponding heat emitters.

The indoor terminal controls the ambient temperature. The water law can

be altered depending on the desired comfort temperature and the variance

between that and the actual measured temperature.

Functions accessible via the indoor terminal:

 Clock settings (times and day).

 Ambient temperature set point.

 Unoccupied period management.

 Comfort / forced economy modes.

 Freezing protection mode.

 Unit fault display in the form of error codes.

All the parameters needed to manage DHW production are accessible on the

control display located inside the machine. Several DHW production modes

are available :

 Comfort mode : Priority given to DHW production without any time or

electricity tariff constraints.

 Economy mode : DHW is only produced during off-peak periods or in

accordance with times programmed in the controller.

 Immediate running : The machine keypad can be used to force DHW

production. At the end of the cycle the system reverts automatically to

normal running.

The Legionnaires' disease protection function is included in the standard

control system.

Operating Diagram - Two-stage Cycle with Economiser and Partial Injection

COND

ECO

Injection expansion valve

Main expansion valve

Low pressure

High pressure

Medium pressure

COND : Condenser

ECO : Economiser

LP : Low pressure

HP : High pressure

Operating cycle

The PAC HT operates on a two-stage compression cycle.

It uses two compressors :

- the larger (C1) for the Low Pressure (LP) stage.

- the smaller (C2) for the High Pressure (HP) stage.

The economiser (refer to above diagram) located at the condenser outlet,

receives some of the HP liquid (point 4) which, after expansion (point 7),

cools the main liquid circuit and generates cooled gas that is mixed with the

gas coming from the LP compressor (point 8).

This economiser has two functions :

- Sub-cooling the liquid to increase the evaporator's and therefore the heat

pump performance, both in heating mode and in domestic hot water

production mode.

- Generating cooled gas to cool the HP compressor suction side.

When the LP or the HP compressor operates on its own, its cycle is identical

to that of a traditional single compressor cycle.

Compressor operation

The action on the two 4-way cycle inversion valves V1 and V2 creates the

following operating modes :

- C2 (HP) compressor on its own.

- C1 (LP) compressor on its own,

- C1 and C2 compressors together.

- De-icing with the C1 compressor on its own.

When heating needs are low and the water outlet temperature required is

below 55 °C, the small compressor C2 operates on its own. The machine

runs in normal mode but at a reduced capacity within an outdoor temperature

range of +20 °C to 0 °C by producing hot water at temperatures between

+35 °C and +55 °C.

Within these same operating limits (outdoor temperatures and hot water

temperatures), the larger compressor C1 operates instead of the smaller one

when the heating needs are greater.

When the outdoor conditions are between +7 °C and -20 °C, the heat pump

switches to high capacity mode with both compressors operating in series to

produce hot water at temperatures between +50 °C and +65 °C.

1 1

General Hydraulic Layout for a Type 1 (*) Installation

Layout 1 :

This layout is recommended when the PAC HT water flow is continuous and close to the nominal value (no radiator thermostatic valves).

The buffer tank (2) provides extra circulating water volume to maintain the minimum volume.

1 Stop valve 12 Expansion tank

2 Buffer tank (optional) 13 In-line heater

3 Filter or sludge trap 14 Bleed

5 3-way valve - Domestic hot water 15 Safety valve

6 Domestic hot water tank

HW : Hot Water

7 Safety devices

CW : Cold Water

8 Recycling circulating pump (optional) * Installation components not supplied

1 1

General Hydraulic Layout for a Type 2 (*) Installation

Layout 2 :

This layout is recommended for heating installations with wide operating water flow variations (radiator thermostatic valves present in the system). We strongly

recommend including the buffer tank (2) as it guarantees that the heating loop capacity is higher than the minimum volume when the maximum number of

thermostatic valves are closed.

The flow adjustment valve (11) is used to balance the flow in heating mode and domestic hot water mode to always ensure optimum PAC HT operation.

1 Stop valve 11 Flow regulating valve

2 Buffer tank (optional) 12 Expansion tank

3 Filter or sludge trap 13 In-line heater

4 Relief valve 14 Bleed

5 3-way valve - Domestic hot water 15 Safety valve

6 Domestic hot water tank

HW : Hot Water

7 Safety devices

CW : Cold Water

8 Recycling circulating pump (optional) * Installation components not supplied

9 Circulation pump

1 1

General Hydraulic Layout for a Type 3 (*) Installation

Layout 3 :

This layout is also recommended for heating installations with wide operating water flow variations (radiator thermostatic valves present in the system). Minimum

system volume is guaranteed by a mixing tank (10). Take care when calculating the volume of water in the installation and only take account of 50% of the mixing

tank's volume.

Example : For a useful volume of 100 litres the actual mixing tank volume will be 200 litres.

The flow adjustment valve (11) is used to balance the flow in heating mode and domestic hot water mode to always ensure optimum PAC HT operation.

1 Stop valve 11 Flow regulating valve

3 Filter or sludge trap 12 Expansion tank

4 Relief valve 13 In-line heater

5 3-way valve - Domestic hot water 14 Bleed

6 Domestic hot water tank 15 Safety valve

7 Safety devices

HW : Hot Water

8 Recycling circulating pump (optional)

CW : Cold Water

9 Circulation pump * Installation components not supplied

10 Mixing tank

Operating Limits

Physical Data

Electrical Data

PAC HT MODELS 12-6 14-7 18-9

REFRIGERANT

Type R407C

COMPRESSORS

Type 2 Scroll compressors

HYDRAULIC CONNECTIONS

Water inlet inch 1" Female

Water outlet inch 1" Female

SOUND LEVELS

Sound pressure levels at 5 m in free field dBA 42 42 42

Sound power levels dBA 67 67 67

DIMENSIONS AND WEIGHT

Length mm 1150 1150 1150

Depth mm 401 401 401

Height mm 1309 1309 1309

Weight kg 195 201 208

PAC HT MODELS 12-6 14-7 18-9

SUPPLY VOLTAGE 1~230 V

Electrical supply cable mm

3 x 6 3 x 6 -

General protection fuse rating A 32 32 -

SUPPLY VOLTAGE 3N~400 V

Electrical supply cable mm

5 x 2.5 5 x 2.5 5 x 2.5

General protection fuse rating A 16 16 16

-15 -10 -5 0 5 10 15 20-20-25 25

Outdoor temperature (°C)

Leaving water temperature setpoint (°C)

Two stage – min. entering water T.

Two stage – max. leaving water T.

Single stage – max. leaving water T.

TWO

STAGE

SINGLE

STAGE

Performance Data

PAC HT MODELS 12-6 14-7 18-9

Outdoor air condition

+7 °C / +6 °C WB

Water condition 30/35 °C

Heating capacity single-compressor kW 6.5 7.9 8.9

Power input kW 1.7 2.0 2.2

COP 3.84 4.00 4.12

Water condition 40/45 °C

Heating capacity single-compressor kW 6.2 7.5 8.4

Power input kW 2.0 2.3 2.5

COP 3.14 3.23 3.36

Water condition 40/50 °C

Heating capacity dual-compressor kW 12.0 14.3 17.9

Power input kW 4.4 4.9 6.1

COP 2.73 2.90 2.93

Outdoor air condition

+2 °C / +1 °C WB

Water condition 50 °C

Heating capacity dual-compressor kW 10.4 12.4 15.4

Power input kW 4.4 4.9 6.1

COP with defrost 2.37 2.50 2.52

Outdoor air condition

0 °C / -1 °C WB

Water condition 65 °C

Heating capacity dual-compressor kW 10.0 12.0 14.8

Power input kW 5.1 6.0 7.3

COP with defrost 1.96 2.00 2.03

Outdoor air condition

-7 °C / -8 °C WB

Water condition 65 °C

Heating capacity dual-compressor kW 8.9 10.7 13.1

Power input kW 4.7 5.6 6.6

COP with defrost 1.87 1.91 1.98

Outdoor air condition

-15 °C

Water condition 65 °C

Heating capacity dual-compressor kW 7.3 9.3 11.4

Power input kW 4.2 5.3 6.0

COP with defrost 1.75 1.76 1.88

Outdoor air condition

-20 °C

Water condition 65 °C

Heating capacity dual-compressor kW 6.3 8.5 10.5

Power input kW 3.8 5.0 5.7

COP with defrost 1.66 1.70 1.85

PAC HT MODELS 12-6 14-7 18-9

Nominal water flow m

/h 1.03 1.23 1.48

Available hydraulic pressure - High speed kPa 52 50 48

Operating limits (outdoor temperature) °C -20 °C

Outlet water temperature Min. / Max. °C 25 °C / 65 °C

WB : Wet bulb.

Performance Curves - PAC HT 12-6

Outdoor air temperature [°C]

Heating capacity and power input [kW]

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

T out=60°C

T out=55°C

T out=50°C

T out=45°C

T out=35°C

2-stage operating mode

Small compressor operating mode

T out=65°C

T out=60°C

T out=55°C

T out=50°C

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

0,5

1.5

2.5

3,5

4.5

Outdoor air temperature [°C]

COP

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

Small compressor operating mode

2-stage operating mode

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

Performance Curves - PAC HT 14-7

Outdoor air temperature [°C]

Heating capacity and power input [kW]

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=55°C

T out=50°C

T out=45°C

T out=35°C

T out=65°C

T out=60°C

T out=55°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

2 stage operating mode

Small compressor operating mode

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

0.5

1.5

2.5

3.5

4.5

Outdoor air temperature [°C]

COP

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

Small compressor operating mode

2-stage operating mode

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

Performance Curves - PAC HT 18-9

Outdoor air temperature [°C]

Heating capacity and power input [kW]

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=55°C

T out=50°C

T out=45°C

T out=35°C

T out=65°C

T out=60°C

T out=55°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

2-stage operating mode

Small compressor operating mode

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

0.5

1.5

2.5

3.5

4.5

Outdoor air temperature [°C]

COP

T out=35°C

T out=45°C

T out=50°C

T out=55°C

T out=60°C

T out=65°C

Small compressor operating mode

2-stage operating mode

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20

Pressure Drop Curves

0.5

1.5

2.5

800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800

Domestic hot water tank (optional)

Domestic hot water tank 3-way valve (optional)

Water flow (l/h)

Pressure drop (kPa)

Water flow (l/h)

Circulation Pump Available Pressure/Water Flow Curves

PAC HT 12-6

PAC HT 14-7

700 800 900 1000 1100 1200 1300 1400 1500 1600 1700

Water flow [l/h]

Available pressure [kPa]

Max. flow

Min. flow

Nominal

flow

HS (3)

MS (2)

LS (1)

Water flow [l/h]

Available pressure [kPa]

Max. flow

Min. flow

Nominal

flow

HS (3)

MS (2)

LS (1)

700 800 900 1000 1100 1200 1300 1400 1500 1600 1700

Water flow [l/h]

Available pressure [kPa]

Max. flow

Min. flow

Nominal

flow

HS (3)

MS (2)

LS (1)

700 800 900 1000 1100 1200 1300 1400 1500 1600 1700

PAC HT 18-9

PAC HT - All sizes

100

110

120

130

140

150

Water flow [l/h]

Power input [W]

HS (3)

MS (2)

LS (1)

700 800 900 1000 1100 1200 1300 1400 1500 1600 1700

Circulation Pump Available Pressure/Water Flow Curves (continued)

Circulation Pump Power Input

Dimensions PAC HT

10 1308.50

703

141

349

1150

400.50

1192.60

1236.60

A Electrical power supply

B Inlet water 1" gas female

C Outlet water 1" gas female

E Display

F Main switch

G Water pressure gauge

H High pressure tap

I Low pressure tap

J Remote control

K Anti-vibrations mounts

Minimum Clearances

800

500

400

500

100

800

Unit

Domestic hot water tank (optional) 140 litre buffer tank (optional)

Water

inlet

150

200

Water

inlet

200

500

200

700

Notes

AN AIRWELL GROUP COMPANY

Airwell Group

Airwell Group (Headquarter)

1bis, Avenue du 8 mai 1945

Saint Quentin en Yvelines

78284 GUYANCOURT

France

AIRWELL Italia Srl

Via XXV Aprile 29

20030 Barlassina (MI)

Italy

Tel. +39 0362 525 51

Fax +39 0362 525 690

www.airwell.it

AIRWELL France SAS

1bis, Avenue du 8 mai 1945

Saint Quentin en Yvelines

78284 Guyancourt Cedex

France

Tel. +33 (0) 01 39 44 78 00

Fax +33 (0) 01 39 44 65 17

www.airwell.fr

AIRWELL Deutschland GmbH

Berner Str. 43

D-60437 Frankfurt

Germany

Tel. +49 (0) 69 50 70 21 20

Fax +49 (0) 69 50 70 22 50

www.airwell.de

AIRWELL Ibérica S.A.

Avenida Castilla, 50

28830 San Fernando de Henares

(Madrid)

Spain

Tel. +34 91 710 04 60

Fax +34 91 710 91 96

www.airwell-iberica.es

www.airwell.com

Ref. : EDM PACHT-A.2GB/02.11 - Supersedes : EDM PACHT-A.1GB/11.08

As part of our ongoing product improvement programme, our products are subject to change without prior notice. Non contractual photos.

Airwell PAC HT Series Engineering Data Manual

Brand: Airwell

Model: PAC HT Series

Category: Heat pumps

Type: Engineering Data Manual

This manual is also suitable for

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Airwell PAC HT Series Engineering Data Manual

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Airwell PAC HT Series Engineering Data Manual

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