Bosch DOMESTIC HOT WATER HEAT PUMP User manual

DOMESTIC HOT WATER HEAT PUMP
This document is confidential and restricted to exclusive use by the official technical
assistance of Bosch in the countries of destination of this product.
TECHNICAL MANUAL FOR AFTER SALES AND
SERVICE TECHNICIANS

Page 2 from 63 6720649497 SM HP270-1 2012/09 en
1.INTRODUCTION............................................................................................ 3
1.1 GENERAL DESCRIPTION ............................................................................................................ 4
1.2 PRODUCT PRESENTATION ......................................................................................................... 5
1.3 WORKING PRINCIPLE ................................................................................................................ 6
2.HEAT PUMP ELEMENTS .............................................................................. 7
2.1 ANODE PROTECTION................................................................................................................ 8
2.2 ELECTRICAL RESISTANCE AND THERMOSTAT........................................................................... 10
2.3 COIL FOR EXTERNAL SOURCE OF ENERGY ................................................................................ 12
3.MODULE ...................................................................................................... 12
3.1 COMPONENTS AND CHECKS IN THE REFRIGERATION UNIT......................................................... 13
3.2 COMPONENTS SYSTEM........................................................................................................... 14
3.3 MAIN COMPONENTS DATA...................................................................................................... 17
3.4 ELECTRICAL MEASUREMENTS................................................................................................. 19
4.COMPONENTS OVERVIEW........................................................................ 23
4.1 COMPRESSOR........................................................................................................................ 23
4.2 FILTERS AND DRIERS.............................................................................................................. 27
4.3 EXPANSION VALVE ................................................................................................................. 27
4.4 PRESSURE CONTROL BY NORMALLY CLOSED PRESSURE SWITCH ............................................... 28
4.5 EVAPORATOR ........................................................................................................................ 29
4.6 CONDENSER.......................................................................................................................... 30
5.HUMAN MACHINE INTERFACE – HMI....................................................... 31
6.MAINTENANCE AND PREVENTIVE ACTIONS .......................................... 37
6.1 CORROSION........................................................................................................................... 37
6.2 WATER QUALITY .................................................................................................................... 37
6.3 TYPES OF SCALE.................................................................................................................... 39
6.4 MAINTENANCE ACTIVITIES FOR TECHNICIANS............................................................................ 40
7.TROUBLESHOOTING.................................................................................. 47
7.1 FAILURES PREVENTION AND DETECTION................................................................................... 50
7.2 EVAPORATOR UNDER PERFORMANCE ...................................................................................... 51
7.3 CONDENSER UNDER PERFORMANCE ........................................................................................ 52
7.4 OTHER RECOMMENDATIONS AND DEFINITIONS .......................................................................... 53
7.5 SERVICE NEEDS..................................................................................................................... 54
7.6 TERMINOLOGY ....................................................................................................................... 55
8.APPENDIX.................................................................................................... 59

Page 3 from 63 6720649497 SM HP270-1 2012/09 en
1. Introduction
Domestic Hot Water Heat Pumps (DHW-HP), with or without air connections ducts, use the heat existing in the
surrounding air, or the waste heat from the indoor air, as energy source for DHW preparation.
These machines are commonly known as air-source hot water heat pump and they are energy-saving and
environmentally friendly equipment with a plug-and-play system structure and easy maintenance.
The heat pump has generally three operation modes:
-normal mode – only heat pump operation;
-combi mode– heat pump and electric resistance operation;
-electric heater mode– only electric resistance operation;
The heat source can be the waste heat as referred, but also the potential energy of unheated rooms, or the air
discharged from rooms with high humidity such as bathrooms, toilets and laundry rooms.
TTNR Brand Temp. Coil Commercial product name Product designation Market
7736500782 Bosch +5º/+35º Yes Compress 3000 DWFI HP 270-1E 1 FIV/S FR, GR
7736500891 Bosch +5º/+35º No Compress 3000 DWFI HP 270-1E 0 FIV/S FR
7736500989 Bosch -10º/+35º Yes Compress 3000 DWFO HP 270-1E 1 FOV/S FR, DK, GR
7736500991 Bosch -10º/+35º No Compress 3000 DWFO HP 270-1E 0 FOV/S FR
7736500781 Buderus +5º/+35º Yes Logatherm WPT 270 I-S HP 270-1E 1 FIV/S DE, BE, PL,
CZ, AT
7736500890 Buderus +5º/+35º No Logatherm WPT 270 I HP 270-1E 0 FIV/S DE, BE, PL,
AT
7736501013 Buderus -10º/+35º Yes Logatherm WPT 270 A-S HP 270-1E 1 FOV/S DE, BE, PL,
CZ, IT, AT
7736501014 Buderus -10º/+35º No Logatherm WPT 270 A HP 270-1E 0 FOV/S DE, BE, IT,
PL, AT
7736500884 elm leblanc +5º/+35º Yes Ondea PAC 270 AI-S HP 270-1E 1 FIV/S FR
7736500885 elm leblanc +5º/+35º No Ondea PAC 270 AI HP 270-1E 0 FIV/S FR
7736501015 elm leblanc -10º/+35º Yes Ondea PAC 270 AE-S HP 270-1E 1 FOV/S FR
7736501016 elm leblanc -10º/+35º No Ondea PAC 270 AE HP 270-1E 0 FOV/S FR
7736500169 Junkers +5º/+35º Yes SupraECO W SWI 270-1X HP 270-1E 1 FIV/S
DE, BE, PL,
CZ; ES, PT,
AT
7736500883 Junkers +5º/+35º No SupraECO W SWI 270-1 HP 270-1E 0 FIV/S DE, BE, PL,
ES, PT, AT
7736500988 Junkers -10º/+35º Yes SupraECO W SWO 270-1X HP 270-1E 1 FOV/S DE, BE, PL,
IT, CZ, AT
7736500990 Junkers -10º/+35º No SupraECO W SWO 270-1 HP 270-1E 0 FOV/S DE, BE, IT,
PL, AT
7736501149 Vulcano +5º/+35º Yes AquaEco HP270-1 E S HP 270-1E 1 FIV/S PT
7736501236 Vulcano +5º/+35º No AquaEco HP270-1 E C HP 270-1E 0 FIV/S PT
Table 1: Appliances overview

Page 4 from 63 6720649497 SM HP270-1 2012/09 en
1.1 General description
This model of domestic hot water heat pump provides hot water for residential purposes, using a closed refrigerant
unit filled with a refrigerant gas (R134a). This ensures the energy production taking out the energy from a cold
source - air, and delivering this energy to a secondary circuit – water - where a simple circulation pump, ensures
water movement through a heat exchanger, heating the water stored in a tank.
(a) (b)
Pict.1 (a) Refrigeration Unit and (b) Storage Tank (with coil)
The engine absorbs energy “Qc” from a cold source (heat absorbed from air) and expels energy “Qh” to a hot
destination (heat delivered to water) while Work “W” is done in the refrigerator circuit (electrical supply). The work
done is ensured by an electrical plug that supplies electricity to the compressor and the movement of the refrigerant
gas R134a ensures the transport of the energy from “Qc” to “Qh”.
Pict.2 – Heat Pump close circuit representation
Compressor
(W)
Heat sink
(Qh)
Condenser
Evaporator
Heat source
(Qc)
Expansion
Valve
Flow
direction

Page 5 from 63 6720649497 SM HP270-1 2012/09 en
1.2 Product presentation
Apart of the main function of the heat pump operation with the required mandatory components of an air/water heat
pump with electrical backup installed for any eventual need, the heat pump has, in some of the models, an internal
integrated coil for external energy source as integration with existent standing or wall hung boiler or even solar
energy installation.
Picture 3 shows the internal constitution and main components:
1) Fan and evaporator group
2) Compressor
3) Condenser (Plate Heat Exchanger)
4) Filter dryer and expansion valve
5) Water circulation pump
6) Storage tank
7) Electrical resistance for backup
8) Internal coil for external backup (eg. solar)
Pict.3 – Main Elements of the Heat Pump (model +5ºC / +35ºC)
1
2 4
3
5
6
7
8

Page 6 from 63 6720649497 SM HP270-1 2012/09 en
1.3 Working principle
The heat pump working principle is based on the transfer of the heat, and not on conversion of electrical energy
into heat. It removes energy from a low temperature source (ambient air) and transfers it into a high temperature
source (hot water tank).
Pict.4 – Energy and electrical input
Electricity is used to upgrade the comfort (temperature) of heat energy and not to generate heat energy. That is the
reason why COP (Coefficient Of Performance) of the heat pump is higher than 3 (which corresponds to an
efficiency of 300 %).
Pict. 5 – Generic overview of the 4 stages of gas
1. Liquid refrigerant R 134a boils at a low temperature in the evaporator. The output is a low temperature and low
pressure vapour.
2. Vapour pressure and temperature increase in the compressor. The electric motor is used to drive vapour
through the compressor and increase vapour temperature and pressure.
3. Heat exchange is done in the condenser. The refrigerant transfers heat to the water and cools up, condensing
and leaving energy there.
4. The liquid returns to the evaporator after passing through an expansion valve. The refrigerant pressure
decreases and the liquid evaporate again.
1
2
3
4

Page 7 from 63 6720649497 SM HP270-1 2012/09 en
2. Heat Pump Elements
The top EPP cover must be carefully disassembled before any intervention on the module. Follow instructions from
picture 6, existent in the sticker on the back of the tank.
Pict.6 – Disassembling of top cover
In front of the appliance and protected by an EPP front panel (fixed to the tank with 4 magnets), it is possible to find
the magnesium anode and the electric resistance for backup.
Pict.7 – Front view of the heat pump

Page 8 from 63 6720649497 SM HP270-1 2012/09 en
2.1 Anode Protection
The anode, installed in the water heater tank, will slowly dissipate whilst protecting it. The life of the water heater
tank is ensured by the periodical inspection, done by an authorised person, replacing it when required.
The anode inspection period shall take in consideration that, for softened water supply or in areas of worse water
quality, it is recommended to inspect it more often and for some other critical different situations, a water treatment
is recommended.
The DIN 4753 determines that all magnesium anodes must be checked, at least each two years (considering
normal conditions), ensuring a visual control.
The acceptable water quality to the heat pump storage tank requires:
-Water pH between 6,5 and 9,5
-Hardness range ≥3.0 ºdH.
Depending on the appliance production date, the anodes can have a measured terminal, or not. Those which do
not have a measurements terminal need a direct visual inspection to ensure its efficient operation and consequent
life time of the tank. Anodes with measurement terminal must be connected to the HMI in order to ensure correct
operation.
(a) Anode without terminal (non isolated) (b) Anode with terminal (isolated)
Pict.8 – Magnesium anode and measurement connections
Pict.9 – Magnesium anode with measurement terminal

Page 9 from 63 6720649497 SM HP270-1 2012/09 en
An anodic current meter can be used to measure the current and evaluate the anode time life. The measured value
shall be higher than 0,3 mA.
Attention: For a correct measurement, the tank must be full with water! The electrical connection must be ensured
after measurement.
Pict.10 – Anodic current measurement with an anode tester or a multimeter
Anyway, a visual inspection is strongly recommended every 2 year, in order to identify an eventual start of a crack
in a part of the anode, or eventually the calc deposition over the magnesium anode surface which will decrease the
anodic current as well, but will also disable the protection function of the anode.
The visual inspection should include a material surface, weight, diameter and length changing control.
Pict.11 – Example of used magnesium anodes

Page 10 from 63 6720649497 SM HP270-1 2012/09 en
2.2 Electrical Resistance and Thermostat
A thermostat control activates the electric resistance of 2kW immerged in the storage tank. This component has a
safety function set at 90ºC, limiting the temperature from an external source (solar, boiler, etc, …) to 80ºC.
Pict.12 – Electric Resistance (2 kW)
Pict.13 – Bipolar thermostat interfaces
Pict.14 – Check voltage supply o the thermostat
Temperature
adjustment