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2 Specifications and Controls2.3 Heat Pump Operating SequencesASHE65, ASHE85 and ASHE125PumpPumpFanFanCompressorCompressor4-way Valve4-way ValveHeatDemandDefrostDemandTime (secs)Time (secs)on15offFigure 2-5: Normal operating sequenceon25 30off25 30off10 25 30Figure 2-6: Defrost cycleASHE175 and ASHE215PumpPumpFanFanCompressor 1Compressor 1Compressor 2Compressor 24-way Valve4-way ValveHeatDemandDefrostDemandTime (secs)on15 20Figure 2-7: Normal operating sequenceoffTime (secs)on25 35 40Figure 2-8: Defrost cycle2.4 ControlsSpecifications andControlsAll Grant Aerona Heat Pumps aresupplied with 2 controllers. 1 x heatpump controller (ATC) and 1 xtemperature controller (BTC).8The ATC is positioned inside thehouse/building and is normally used inan automatic condition. There are a fewparameters that can be adjustedincluding time and maximum watertemperature. The details of thesesettings can be found in Section 11 ofthis manual.The BTC is a split temperaturecontroller located inside the heat pump.For many installations, the HWtemperature and the CH temperaturewill be different. The BTC allows for 2different design temperatures to beentered, maximising the efficiency of theGrant Aerona heat pump. The details ofthese settings can be found in Section11 of this manual.All other controls (programmers,motorised valves, thermostats, etc) arenot supplied but their use is covered inSections 4 and 8 of this installationmanual.Figure 2-9: ATC ControllerFigure 2-10: BTC Controller

2.5 Pump ump Head (metres)61(Min)00123Q (m3/h)456Figure 2-11: Pump curves for ASHE65, ASHE85 (RS-15/6) and ASHE125 (RS-25/8)20181412H (metres)PUN-200E1086400102030405060Flow (m3/h)Figure 2-12: Pump curve for ASHE175 and ASHE215708090100Specifications andControls29

2 Specifications and Controls2.6 Performance GraphsASHE65ASHE175730712625610563Output in -12-1573571463065255Output in 2525!762015431025100151272-3-7-12-15COPOutput in kW5NOTEAll Grant ASHE Heat Pumps havebeen independently third partytested to BS EN 14511: 2007.The COP data given above is basedon 7 C ambient air and 35 C watertemperature. This information shouldbe used as guidance only andshould not be used to estimate theCOP at other temperatures.-7-12-15COP208COP4Output in kW1610Specifications andControls-7ASHE2151210COP8520COPOutput in kW14

3 Siting the Heat Pump3.1 Position1. BaseThe heat pump should be installedon a flat trowelled finished concretebase 150mm thick. This baseshould extend at least 100mmbeyond the unit on three sides. Theedge of the concrete base on theside closest to the building shouldbe flush with that face of the heatpump. Refer to Figure 3-1.300mmminimumDeflectorplate (not onASHE125)To avoid bridging the DPC, leave agap of at least 300mm between theconcrete base and the wall of thehouse.Edge of baseflush with rearof heat pumpDPC200mm min aboveground levelConcrete base150mmminimumTrench with chippingsFigure 3-1: Installation detailsIMPORTANTIt is essential that the condensate is able to drainaway and not allowed to run onto any adjacentpaths or driveways where, in winter, this will resultin icing and a potential hazard for anyone walkingnear the heat pump.The top of the concrete base must be either level with,or above, the surrounding ground level. Always ensureat least 200mm vertical clearance between thesurrounding ground level and the underside of theheat pump to allow for adequate air movement. Referto Figure 3-1 for details.2. ClearancesThe Heat pump should have aminimum of 300mm from the rearof the unit to any wall and not haveany obstruction within 1000mmfrom the front or either side of theunit. Do not rest objects on top oragainst any part of the heat pumpunder any circumstances. Do notinsert objects into the fan guard.3. Noise LevelAll heat pumps make a noise.Discuss the potential nuisancefactor with the end-user whenconsidering the final position of theheat pump. Take opening windowsand doors into account. It is notessential for the heat pump to bepositioned next to a wall of thehouse. Behind an out-building maybe more suitable so discuss theoptions with the end-user.4. InsulationRemember, all pipe work,irrespective of length, must be wellinsulated to prevent heat loss. Theuse of barrier plastic pipe togetherwith double thick insulation isstrongly recommended, particularlywhen considering longer pipe runs.Siting the Heat PumpThe Underside of the heat pump isfitted with a condensate deflectorthat directs the condensate to therear of the unit. To allow thiscondensate to safely drain away,there should be a shallow trench atleast 150mm wide, filled with stonechippings, along the rear edge ofthe concrete base. This trench canextend across the gap between theconcrete base and the house(minimum distance 300mm) but thechippings must be below thebuilding DPC level.100mmmin11

3 Siting the Heat Pump3.2 OrientationThe North face of a building will usuallyhave colder ambient air than any otherside. To ensure maximum efficiencyfrom the Grant Aerona heat pump,position the unit on a warmer side. Inorder of preference, site the unit on aSouth face followed by either SouthEast or South West, then by East orWest. Only install on a North face ifthere is no other alternative.Cooler ambient airNorthEastSouthSiting the Heat PumpFigure 3-2: Location of air source heat pump12

4 Hydraulic DiagramsThe following are examples of suitable systemsIMPORTANT4.1 S-Plan Type - MonovalentThe following system diagramsare only concept drawings andnot detailed engineeringdrawings. They are not intendedto describe complete systems,nor any particular system.Internal wiringcentreProgrammerCylinderStatIt is the responsibility of thesystem designer, not GrantEngineering UK Ltd., todetermine the necessarycomponents for andconfiguration of the particularsystem being designed includingany additional equipment andsafety devices to ensurecompliance with building andsafety code requirements.RoomStatHW FlowCH FlowHeating LoadCH ReturnOutsidewallFlowGrant AeronaHeat PumpHW ReturnHeat sFlexiblepipeIsolatingvalveReturnFigure 4-1: Monovalent system - with S-Plan type controls4.2 Extended S-Plan Type - MonovalentProgrammerInternal wiringcentreCylinderStatCH FlowHW FlowRoomStatHeating LoadRoomStatOutsidewallHeating eHW ReturnCondenserIsolatingvalveCH ReturnFlowGrant AeronaHeat PumpHydraulic DiagramsHeat PumpATCReturn13Figure 4-2: Monovalent system - with extended S-Plan type controls

4 Hydraulic DiagramsIMPORTANTThe following system diagrams areonly concept drawings and notdetailed engineering drawings.They are not intended to describecomplete systems, nor anyparticular system.It is the responsibility of the systemdesigner, not Grant Engineering UKLtd., to determine the necessarycomponents for and configuration ofthe particular system beingdesigned including any additionalequipment and safety devices toensure compliance with buildingand safety code requirements.The following are examples of suitable systems4.3 S-Plan Type - BivalentInternal wiringcentreProgrammerCylinderStatRoomStatHW FlowCH FlowRecommendedmaximum flowtemp. 60 CBoilerMaximumreturn temp. Outside48 CwallRFBoiler CirculatingPump (see note below)FlowGrant AeronaHeat veFlexiblepipeIsolatingvalveHydraulic DiagramsReturn14Figure 4-3: Bivalent system - with boiler manifold and S-Plan type controls!NOTEBoiler circulating pump maybe fittedin Return (between manifold andboiler).Check with boiler manufacturer forguidance on pump location.Auto BypassHW ReturnHeat PumpATCCH ReturnPump delay onBTC must be setfor 2 mins. Referto Section 11.4Heating Load

4.4 Extended S-Plan Type - BivalentInternal wiringcentreProgrammerCylinderStatRoomStatHW FlowCH FlowHeating LoadRecommendedmaximum flowtemp. 60 CBoilerMaximumreturn temp. Outsidewall48 CRFBoiler CirculatingPump (see note urnValveFlexiblepipeRoomStatHW ReturnHeat PumpATCGrant AeronaHeat PumpHeating LoadCH ReturnPump delay onBTC must be setfor 2 mins. Referto Section 11.4CH FlowAuto BypassIsolatingvalveReturnFigure 4-4: Bivalent system - with boiler and extended S-Plan type controls!NOTEHydraulic DiagramsBoiler circulating pump maybe fittedin Return (between manifold andboiler).Check with boiler manufacturer forguidance on pump location.15

4 Hydraulic Diagrams4.5 Buffers TanksIMPORTANTWhen considering the use of a buffer,also consider the space the buffer willtake up – it may not be possible tohouse both a cylinder and a buffer tank.The use of a buffer with the currentAerona heat pump is not necessary inthe majority of installations. However, it ispossible to utilise a buffer if the end-userwishes to store hot water when there isno other demand placed on the system.There are two main considerations whendeciding when and where a buffer tankshould be used.The following system diagramsare only concept drawings andnot detailed engineeringdrawings. They are not intendedto describe complete systems,nor any particular system.It is the responsibility of thesystem designer, not GrantEngineering UK Ltd., todetermine the necessarycomponents for andconfiguration of the particularsystem being designed includingany additional equipment andsafety devices to ensurecompliance with building andsafety code requirements.The following diagrams show both anS-Plan and an extended S-Plan for usewith a buffer tank.!1. It may act as an initial boost when aheating demand is placed on thesystem from cold.NOTEWhen using a buffer tank with theheat pump, the weathercompensation function of the built-inBTC controller is NOT used.2. Storing water for this function willresult in heat losses from the bufferover time, reducing the overall COPand therefore the overall efficiency ofthe heat pump and the system.A cylinder thermostat (withimmersion probe) should be fitted tothe buffer tank. This must be wiredto switch between terminals 1 & 3(the Common and HW terminals) onthe S-Plan controls terminal block inthe heat pump control panel. Referto Figure 8.15 in Section 8 for wiringdiagram. The BTC setting for ‘DHWBOIL TARGET’ should be set to 48 C.4.6 S-Plan with Buffer - MonovalentInternal wiringcentreProgrammerCylinderStatRoomStatCH FlowHWFlowHeating LoadHeat gvalveReturnFigure 4-5: Monovalent system - with Buffer and S-Plan type controls16HW ReturnBuffertankIsolatingvalveCH ReturnFlowGrant AeronaHeat PumpCondenserHydraulic DiagramsOutsidewall

4.7 Extended S-Plan with Buffer - MonovalentInternal wiringcentreProgrammerCylinderStatRoomStatCH FlowHWFlowHeating LoadHeat PumpATCBuffertankHW ReturnFlowGrant AeronaHeat PumpCH urnFigure 4-6: Monovalent system - with Buffer and extended S-Plan type controls!NOTEHydraulic DiagramsThe hydraulic diagrams do not showthe isolation valves, any expansionvessels, pressure relief valves orfilling loops. More information onthese components can be found inSection 7.17

5 System Design CriteriaUnlike a typical condensing oil or gasfired boiler that operates at a flow of70 C and a return of 50 C, a heat pumpoperates with a flow of between 30 Cand 50 C. The return temperature willdepend on the load of the system at agiven point in time.The design of any system in the UK istypically based on 2 parameters.1. That the outside air temperaturecan fall to as low as -3 C and thatthe house comfort temperature willbe 21 C.The BTC incorporated in the heatpump will adjust the outputaccording to the external ambientair temperature but the systemmust be designed in the first placeto meet this maximum demand.2. The second factor to consider isachieving this maximum demandusing much lower watertemperatures than with oil or gasfired appliances.Designing a new system for usewith a low-grade heat source isstraight forward, and assuming theinsulation properties of the dwellingmeets or exceeds current buildingregulations, there should be noissue with achieving the heatdemand.The use of a heat pump in an existingsystem can be straightforward if thefollowing rules are followed.1. The loft has insulation to a depthof 270mm2. Cavity wall insulation has beeninstalled3. The radiators have been changedor upgraded to match the newwater temperatureSystem DesignCriteria4. An accurate heat loss calculationfor each room of the house hasbeen carried out185. All primary and secondary pipeshave been well insulated to preventheat lossIt must be understood that your final design workingtemperature will have an effect on the overall systemefficiency, the COP of the heat pump and thecomplete system. Put simply, the lower your designworking temperature, the better the COP. If you arein any doubt about the suitability of the heatingsystem, stop and seek the advice of a qualifiedheating engineer or experienced system designer.While underfloor heating is the preferredheat emitter, a combination ofunderfloor heating and radiators, orradiators only, works just as efficiently. Itis necessary, however, to calculate thesize of radiator required accurately– if this is not done, the house will failto reach the target temperature and willbe costly to rectify after the installationis complete.Refer to Section 6 to determine the sizeof radiators required for yourinstallation.When tested to BS EN14511, theCoefficient of Performance and HeatOutput for an Air Source Heat Pumpare declared at the test conditions of7 C outside air temperature and 35 Cwater flow temperature.At all other values of outside airtemperature and water flowtemperature the actual Heat Pumpoutput will vary, e.g. the heat output will:a) decrease with lower outside airtemperatures and increase with higheroutside air temperatures at any givenwater flow temperature, andb) decrease with higher water flowtemperatures and increase with lowerwater flow temperatures at any givenoutside air temperatureThe factory fitted 3kW electricimmersion heater should not be addedto the rated output of the Heat Pumpfor sizing/selection purposes. Thiselectric immersion heater serves as aback-up and will only be called intooperation when the heat pump isoperating at low air temperatures.Provided that the Heat Pump is sizedcorrectly for the system, this back-upheater will compensate for any short fallin meeting the design heat load for theproperty at the minimum design airtemperatures.

6 Calculating Radiator SizesExisting SystemsMost existing wet heating systems willuse radiators as emitters. When theoriginal system was installed, theradiators would have been sizedaccording to the manufacturer’sspecifications. Typically, this would havebeen 82ºC flow and 71ºC return withthe connections being flow at the topand return at the opposite bottomcorner.With the advent of condensing boilers,most installations were found to haveoversized radiators and as such, little orno adverse effects were found whenthe system temperatures fell to 70ºCflow and 50ºC return.However, as heat pumps work attemperatures lower than even this, it isimportant that each radiator is checkedagain for its suitability and replaced withone of the correct size/output ifnecessary.Below is a typical radiator correction factor table* and a worked example of sizing radiators for use with a heat pumpA typical heat pump operating to feed radiators will run at a flow temperature of 50ºCand a return temperature of 40ºC – giving a mean water temperature of 45ºC.ºCCorrection Factor50.050100.123150.209In the case of a system using both radiators and Underfloor heating (UFH) a flow of40 C and a return of 30ºC – giving a mean water temperature of 35ºC – would usuallybe preferred.200.304For a living room with a design temperature of 21ºC and heat loss of 1.8kW.250.406300.515350.629From the radiator manufacturers correction factor table: for T 24 C factor 0.406.400.748For a design heat loss of 1.8 kW: the required corrected output is 1.8 / 0.406 4.43kW.450.872501.000551.132Select a radiator from manufacturer’s information that would give 4.43kW output (at75 C mean water temperature) – this will give the required 1.8 kW output at 45 Cmean water temperature produced by the heat pump.601.267651.406701.549751.694The T 45ºC – 21ºC 24ºC.Similarly, for a bedroom with the same design heat loss but design temperature of 18 C.The T 45 C – 18 C 27 C.From the radiator manufacturers correction factor table: for T 27 C factor 0.46.Please advise the customer that, inany case, the radiator will not get‘hot’. The perception may well bethat the system is not workingcorrectly because the radiators areonly ‘warm’.For a design heat loss of 1.8 kW: the required corrected output is 1.8 / 0.46 3.48kW.Thus, select a radiator from manufacturer’s information that would give 3.48kW outputto give the required 1.8 kW output at 45 C mean water temperature.* Where possible reference should be made to radiator manufacturers owninformation for the correction factors for different types of radiator.CalculatingRadiator SizesAs can be seen, the size of radiatorrequired will be larger than conventionalsystems. This can be controlled to anextent by choosing a suitable designwater temperature. The trade off will bea slightly lower COP. As we havealready discussed, the higher therunning temperature, the harder theheat pump has to work to reach thedesired temperature.19

7 Sealed SystemsThe following components are requiredto use the Grant Aerona heat pump aspart of a sealed heating system. Due tothe lack of space these componentsare not located within the heat pump,but have to be fitted external to theunit.a) expansion vessel (of the correct sizeto suit the volume of the system)b) Pressure relief valve – 3 barc) Pressure gauged) Filling loope) TundishThese items may already be installed onthe existing system. If so, they shouldbe checked to ensure the integrity andsuitability of the components beforeproceeding to re-use them.The filling loop can be sited anywhere inthe system, but it must always be sitedwithin visual distance of the pressuregauge. The nominal filling pressure forthe system when cold is 1 bar.Refer to Section 15 for details of theGrant sealed system kits designed foruse with the Grant Aerona heat pumprange.Before filling the system check theexpansion vessel charge pressure. Thisshould be 0.2 – 0.3 bar higher than thecold fill pressure for the system.The expansion vessel can be fitted toeither the flow or return pipes butensure that there is no automatic ormanual valve in line that may preventthe heat pump utilisi

Grant ASHE Air Source Heat Pump Air to Water High Efficiency Heat Pump Range Installation & User Instructions Part No. DOC.93 Rev.00 April 2013 Tested to BS EN 14511 PROVISIONAL COPY. 2 STOP . 8.11 Bivalent Electrical Diagram 30 9 Domestic Hot Water 31 9.1 Temperature Control 31 9.2 Heat Pump Cylinders 31 9.3 Temperature Boost 31