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
2
Dual zone system installation (radiators and under-floor heating)
Installation examples
Single zone system installation (radiators)
PAC HT
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
Insulated underground hot water pipes
3
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).
4
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.
5
Operating Diagram - Two-stage Cycle with Economiser and Partial Injection
HP
C2
COND
ECO
C1
LP
1
Injection expansion valve
Main expansion valve
Low pressure
High pressure
Medium pressure
6
2
4
5
7
3
8
9
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.
3
2
1
1
1
3
1
HW
CW
5
6
7
8
1 1
15
14
13
1
12
1
1 1
1
6
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
3
2
1
1
1
3
1
5
6
7
8
9
4
14
13
15
11
1
12
1
1
1 1
1 1
HW
CW
7
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
3
1
1
1
3
1
5
6
10
7
8
9
4
14
13
15
11
1
12
1
1
1 1
11
1
1
HW
CW
8
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
9
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
2
3 x 6 3 x 6 -
General protection fuse rating A 32 32 -
SUPPLY VOLTAGE 3N~400 V
Electrical supply cable mm
2
5 x 2.5 5 x 2.5 5 x 2.5
General protection fuse rating A 16 16 16
10
15
20
25
30
35
40
45
50
55
60
65
70
-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
10
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
3
/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.
11
Performance Curves - PAC HT 12-6
0
2
4
6
8
10
12
14
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
0,5
1
1.5
2
2.5
3
3,5
4
4.5
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
12
Performance Curves - PAC HT 14-7
0
2
4
6
8
10
12
14
16
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=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=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
0.5
1
1.5
2
2.5
3
3.5
4
4.5
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
13
Performance Curves - PAC HT 18-9
0
2
4
6
8
10
12
14
16
18
20
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=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=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
0.5
1
1.5
2
2.5
3
3.5
4
4.5
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
14
Pressure Drop Curves
0
0.5
1
1.5
2
2.5
800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800
0
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)
Pressure drop (kPa)
Water flow (l/h)
15
Circulation Pump Available Pressure/Water Flow Curves
PAC HT 12-6
PAC HT 14-7
0
10
700 800 900 1000 1100 1200 1300 1400 1500 1600 1700
20
30
40
50
60
70
Water flow [l/h]
Available pressure [kPa]
Max. flow
Min. flow
Nominal
flow
HS (3)
MS (2)
LS (1)
0
10
20
30
40
50
60
70
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
16
0
10
20
30
40
50
60
70
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
50
60
70
80
90
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
17
Dimensions PAC HT
10 1308.50
I
H
G
F
E
703
141
85
C
B
J
A
K
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
18
Minimum Clearances
800
500
400
500
100
800
Unit
Domestic hot water tank (optional) 140 litre buffer tank (optional)
Water
inlet
150
150
200
Water
inlet
200
500
200
200
700
19
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.
/