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Continuous Flow Electric Water Heater

TANDEM GUIDE

DISTRIBUTED BY:

Tandem Hot Water Service

CFEWH SERIES 1-20

Hot water just got smarter

www.microheat.com.au


ISSUE 3 FEB 2014

03

Introduction

Contents

Premium CFEWH

CFEWH SERIES 1-10P

The Exterior Cover includes a display showing Output Water

Temperature and Flow Rate

Standard CFEWH

CFEWH SERIES 1-10S

The Exterior Cover has only a RED/GREEN indicator LED.

IMPORTANT

Installation instructions are covered in the CFEWH SERIES 1-10 INSTALLATION MANUAL.

This Guide provides full details regarding use of two Continuous Flow Electric Water Heater [CFEWH] SERIES 1-10 units in tandem as a hot water system.

The tandem system can utilise either SERIES 1 Premium or Standard models – the photographs below identify the two models.

The CFEWH Tandem hot water system is referred to as CFEWH SERIES 1-20 in this Guide.

VOlTAgE

The CFEWH is Single Phase 240VAC LIVE-NEUTRAL/GROUND.

Full specifications are on page 9 in this Guide.

Introduction 03

About This Product 04

Comparison 06 Electric Instantaneous Water Heating (EIWH) appliances

Compared with the Continuous Flow Electric Water Heater (CFEWH) 06

Tandem Benefits 08 The energy efficiencies of the CFEWH tandem hot water system 08

Specifications 09

Connections 11 Plumbing Connection 11

Electrical Power Connection 11

Reference 12 AS/NZS 3000:2007 Appendix C/Section C2

Maximum Demand Calculation 12

Tandem Installation Example 14

Contact Details 15

The company accepts no responsibility for the failure of this appliance if it has not been installed and operated in accordance with the instructions provided. The information in this Manual is correct as at February 2014, but the manufacturer reserves the right to make changes to specifcations without prior notice. All information provided E&OE. Copyright © 2014 All Rights Reserved. MicroHeat and its associated logo are Registered Trademarks of MicroHeat Technologies Pty Ltd. MicroHeat products are manufactured under one or more Patents, which are in force. The Product is Patent Cooperation Treaty (PCT) Protected, and Trademarks Protected

CFEWH SERIES 1-20 | TANDEM GUIDE ©2014 | MicroHeat Technologies Pty Ltd

04 05

What makes this product so unique and different?The Continuous Flow Electric Water Heater [CFEWH] uses innovative new technology to deliver hot water instantly … and achieve impressive efficiencies in both water and energy usage.

We’d like to explain how it’s so different from other hot water systems – and why it’s setting completely new standards.

To fully appreciate the difference – and the substantial benefits – offered by the technology used in this water heater, we need to start off by comparing the main deficiencies of traditional hot water systems.

Heating water the traditional wayTraditional centralised hot water services consume continuous energy to heat water and then maintain it at a defined (thermostat-controlled) temperature, ready for when it’s wanted. Typically, the water heater is located away from where the water is wanted, relying on lengths of pipe to deliver the water. Energy is therefore wasted keeping quite a large volume of water at a stable temperature – often at a higher temperature than would ever be used.

But that’s not all – water is wasted every time a hot water tap is turned on. That’s because you need “to let the water run” until the water held in the pipes has made way for the hot water you want, coming from the water heater.

The overall result is quite inefficient usage of power together with wastage of water.

The MicroHeat differenceThe engineers at MicroHeat set out to create something completely different from existing methods of providing hot water: a highly efficient new method of heating water that would address the wastage of valuable resources – energy and water.

The Continuous Flow Electric Water Heater [CFEWH] is a very compact unit, which provides an instant and continuous flow of hot water wherever it’s required – delivered through very short lengths of pipe. Water isn’t wasted, because you’re not leaving it running, waiting for it to get hot. Hot water is always at a stable temperature, despite any fluctuations in water pressure.

You don’t need a science degree to understand how the efficiencies and savings are achieved – all you need to do is follow our simple explanation.

The secret of “optimised” energyThe unit intelligently optimises the amount of energy it needs to heat water, depending on how much water you want.

For example, let’s assume hot water is required at 45°C.

If you want a fairly fast flow of water – 4 litres a minute – the unit will use its full power – 9.6kW – to heat the water.

However, if you only want a low flow of water – 1.5 litres a minute – the unit will use just 4.2kW to heat the water.

The benefit is the unit can intelligently vary itself between being a 9.6kW and 4.2kW system. The lower flow rate achieves 56% less energy consumption – and that contributes to lowering power bills.

In addition, varying the flow rate of the water contributes to lower water consumption and achieves further savings. Reducing water flow from 4 litres a minute to 1.5 litres a minute lowers water consumption by 66%.

Incoming water temperature makes a differenceThe unit also achieves savings in another area – by intelligently varying its power between 9.6kW and 7kW to heat incoming cold water.

Depending on where you’re located and what season it is, mains cold water temperature could potentially fluctuate anywhere between 10°C and 25°C.

Let’s again assume hot water is required at 45°C and you want a fairly fast flow of hot water – 4 litres a minute.

If the incoming water temperature is a fairly chilly 10°C, the unit will apply its full power of 9.6kW – however, if it’s a pleasantly warm 25°C, it will only use 7kW. That’s 20% less energy consumption – making a further contribution towards lowering power bills.

We hope you now have a better understanding of how the Continuous Flow Electric Water Heater [CFEWH] is revolutionising hot water.

The benefits – the reduction in both power and water – are even greater when two units are used in tandem, as covered in this guide.

About This Product


Although the Continuous Flow Electric Water Heater [CFEWH] is very safe to use, this appliance is not intended for use by persons (including children) with reduced physical, sensory or mental capabilities, or lack of experience and knowledge, unless they have been given supervision or instruction concerning use of the appliance by a person responsible for their safety. Children should be supervised to ensure that they do not play with the appliance.

About the Continuous Flow Electric Water Heater [CFEWH]


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Comparison

Electric Instantaneous Water Heating (EIWH) appliances

Continuous Flow Electric Water Heater (CFEWH)

To fully appreciate the benefits of the Continuous Flow Electric Water Heater (CFEWH), the starting point is to review the dynamics of typical single phase Electric Instantaneous Water Heating (EIWH) appliances and identify their limitations/shortfalls:

Power RatingThey are restricted to a maximum of 9.6kW/240VAC – 40.0AMPS.

Flow RateAssuming an energy to heat transfer of 100%, the maximum on-demand flow rate achievable at 9.6kW would be 4.0ltr/min, with a maximum temperature change of 35°C.

OperationOnce in operation, conventional Single Phase EIWH Appliances will consume the full rated power, irrespective of the flow rate or the temperature of the incoming water. The implications are:

Increased infrastructure costsAt low flow rates, hot water temperatures will exceed 50°C, therefore requiring the use of tempering valves/thermostatic control valves.

Increased operating costs – and wastage of water• They always operate at full rated power.

• Switch-on flow rate exceeds 2.5ltr/min.

• It is not possible to deliver stable hot water temperatures.

All of the above factors need to be compared with the dynamics of “optimised” energy delivered by the Continuous Flow Electric Water Heater (CFEWH).

Electric Instantaneous Water Heater vs. Continuous Flow Electric Water Heater

HOT WATER SERVICE

EIWH CFEWH

Electrical Supply Single Phase Single Phase

“Optimised” Energy NO YES

Switch-on Flow Rate 2.6ltr/min 1.5ltr/min

Optimised TANDEM Capability NO YES

The key benefits of the CFEWH are:Decreased infrastructure costs• At low flow rates, hot water temperatures cannot exceed 50°C, which

• No requirement for hot water reticulation.

Small Footprint• Facilitates point of use installation.

• Easy to install and virtually maintenance-free: no scaling or furring.

Decreased operating costs – and minimal wastage of water• Always operates at “optimised” power.

• Switch-on flow rate is as low as 1.5ltr/min.

• No requirement to heat water in anticipation of use.

• Stable hot water temperatures are delivered.

• Reduced water consumption due to reduced draw off.

• Significantly reduced hot water reticulation energy losses.

“Optimised” energy is the capacity to heat water far more efficiently – delivering reductions in consumption of both energy and water.

Reduced energy consumption • Lower flow rate = less water volume to be heated and less energy is consumed.

• Lower temperature change required = less energy is consumed.

Reduced water consumption• Hot water temperature stability = less water is consumed.

• The lower the flow rate = less water is consumed.

Of course, the ideal situation would be for EIWH appliances to have some degree of “optimised” energy – however, most do not incorporate this.

Significantly, the 100% “optimised” energy delivered by the CFEWH results in far less than full rated power being consumed.

“Optimised” Energy Key Benefits

therefore eliminates the requirement for tempering valves or thermostatic control valves, unless otherwise specified as per AS 3500.


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Tandem Benefits

The energy efficiencies of the CFEWH Tandem hot water system

Using two CFEWH units in tandem achieves flow rates equivalent to using three phase power, but only using single phase electrical supply – and provides significant benefits from 100% “optimised” energy.

Because water is not heated in anticipation of use, there is minimal standby loss. CFEWH standby (phantom energy) loss is the equivalent of 3 Watts, or 0.072kW-hr/day. Minimum Energy Performance Standards are therefore not required.

Reduced power is required because “optimised” energy results in significantly less than full rated power being consumed by virtue of:

• Lower flow rate.• Higher temperature of incoming water.• Stable output hot water temperatures.• 100% energy to heat transfer.

Because the Single Phase CFEWH does not rely on heat exchange technology, there are further benefits:

• Energy to Heat Transfer 100%.• No thermal inertia = instant response to change.• No transduction losses = reduced energy

consumption.• Reduced heat loss into CFEWH body.

Tandem Benefits

CFEWH SERIES 1 Technical Specifications

SINglE PHASE CFEWH SERIES 1

CFEWH SERIES 1-10

TANDEM CFEWH SERIES 1-20

Electrical Connection

Rated Power (kW) 9.6 19.2

Voltage (VAC) 240 240

Rated AMPS 41 83

Frequency (Hz) 50 50

Unit Parameters

Switch on Flow Rate 1.5 ltr.min 1.5 ltr.min

System Type Continuous Flow Electric Water Heater (CFEWH)

Maximum Rated Operating Line Pressure

10 bar 10 bar

Heating Method Optimised Direct Energy Transfer

Standards

Water ContaminationWaterMark AS/NZS 4020 & AS/NZS 3498

In accordance with AS/NZS 3498 Section 7.2.1 The CFEWH SERIES 1-10 does not require the installation of Tempering Valves OR Thermostatic Control Valves

Electrical SafetyAS/NZS 60335.2.35

IEC 60335.2.35

EMC CE/C-Tick

Specifications

Capacity 400 ml 2 x 400 ml

Dimensions per CFEWH Height 295mm x Width 210.50mm x Depth 125mm (Without Extension Cover)


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Plumbing ConnectionThe tandem connection between the two units should be braided hose with or without a seal, or copper tube – diameter ½”, or any connection means compliant with plumbing standards and regulation.

The distance between units should be no more than 35cms and the connecting pipe should be lagged for thermal insulation.

If using a Premium unit [CFEWH SERIES 1-10P] as the second [hot water outlet] unit, the output temperature should be set to 45°C. However, there may be instances where the output temperature of the water needs to be set lower – for example: early childhood centres, schools, nursing homes or facilities for young, aged, sick or disabled people.

Electrical Power ConnectionWith tandem installations, both units must be fitted with their own respective circuit breaker and isolation switch as shown below.

ConnectionsTandem Benefits

Specifications (cont.)CFEWH SERIES 1 Hot Water Output Temperatures/Flow Rate Tables

The incoming water temperature will vary during Summer and Winter. The following tables show the hot water output temperatures attainable at various flow rates, for each of the CFEWH SERIES 1 Models available.

INLETOUTLET

CFEWH SERIES 1-10

WATERPRESSURE

LIMITING VALVE5 bar/500kpa

SHUTOFF VALVE MUST NOT BEA NON-RETURN TYPE VALVE

CFEWH SERIES 1-20 TANDEM HWS

Hot Water OUT

Cold Water IN

INLETOUTLET

CFEWH SERIES 1-10

Less than 250mm

IMPORTANT


IMPORTANT


CFEWH SERIES 1-10CFEWH SERIES 1-10

IsolationSwitch 2

IsolationSwitch 1

NEUTRAL

EARTH

LIVE

240VAC

NEUTRAL

EARTH

LIVE

240VAC

litres/min

INCOMINg WATER TEMPERATURE 9.6kW TANDEM 19.2kW

6°C 4.1 8.1

10°C 4.6 9.2

15°C 5.5 11.0

20°C 6.9 13.8

litres/min

INCOMINg WATER TEMPERATURE 9.6kW TANDEM 19.2kW

6°C 3.1 6.3

10°C 3.4 6.9

15°C 3.9 7.9

20°C 4.6 9.2

OUTPUT WATER TEMPERATURE 40°C OUTPUT WATER TEMPERATURE 50°C

(Note: 60°C Setting to be used with tempering valves where required.)

Tandem Installation ExampleAn example of a CFEWH SERIES 1-20 tandem installation. The location of the CFEWH SERIES 1tandem units is not limited to the location option shown.

PressureLimiting Valve

Shower 1Flow Rate 9ltrs/min

Shower 2Flow Rate 9ltrs/min

Hand Basin 1Flow Rate 2ltrs/min

Hand Basin 2Flow Rate 2ltrs/min

ShutoffValve

Hot Water OUT

Cold Water IN

IMPORTANT


The CFEWH TANDEM units must be installed in a vertical position on an internal wall, or in an internal cupboard or space.

OR


40A Circuit Breaker

40A Circuit Breaker

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Section C2.1 After diversity maximum demand

As indicated in Clause 2.5 (and explained in Paragraph B3.2), the current in a circuit must not exceed the current rating of the circuit protective device – and this, in turn, must not exceed the current-carrying capacity of the circuit conductors.

For circuits supplying a single item of equipment, the circuit current is simply the nominal load current of the equipment (eg: a 10000W 230/400V three-phase heater has a full per–phase load current of 14.5A). The circuit conductors and the protective device must have a current carrying capacity of not less than 16A (nearest standard rating).

Where more than one item of equipment is connected, the circuit current could be simply assessed as the sum of the individual equipment load currents. While this would provide a safe and conservative solution, it does not take account of the normal operating conditions during which all equipment is not operating simultaneously at full load or for long periods (eg: submains to a distribution board associated with numerous socket outlet circuits). Under such conditions, the circuit current is estimated using diversity factors and is often described as the ‘after diversity maximum demand’.

As stated (in Clause 2.2.2), maximum demand current can be determined by one of four methods – calculation, assessment, measurement or limitation. The following paragraphs of the Appendix C provide information and examples regarding the application of the calculation method for determining maximum demand current in consumers’ mains and submains only.

Section C2.3 Domestic installations C2.3.1 Method

Table C1 provides an allocation of load for different types of equipment connected to consumers’ mains or submains in a single or multiple domestic installations. The load current is calculated for each equipment load group in the installation or affected part thereof, and these contributions are added together to achieve the maximum demand current. The accompanying notes provide clarification of certain provisions and the examples demonstrate how the calculation is made.

ReferenceReference

AS/NZS 3000:2007 Appendix C/Section C2 Maximum Demand Calculation

load group

Single domesticelectrical installation

or individual living unit per phase a

Blocks of living units a,b,c

2 to 5 living units per phase

6 to 20 living units per phase

21 or more living units per phase

loading associated with individual units

A. Lighting(i) Except (ii) and load group H below d,e,f

3 A for 1 to 20 points + 2 A for each additional

20 points or part thereof6 A

5 A + 0.25 Aper living unit

0.5 A per living unit

(ii) Outdoor lighting exceeding a total of 1000 W f,g 75% connected load No assessment for the purpose of maximum demand

B. (i) Socket-outlets not exceeding 10A e,h. Permanently connected electrical equipment not exceeding 10 A and not included in other load groups i

10 A for 1 to 20 points + 5 A for each additional

20 points or part thereof

10 A + 5 A perliving unit



(ii) Where the electrical installation includes one or more 15 A socket-outlets, other than socket-outlets provided to supply electrical equipment set out in groups C,D, E, F, G, and L h,j

10 A

(iii) Where the electrical installation includes one or more 20 A socket-outlets other than socket-outlets provided to supply electrical equipment set out in groups C, D, E, F, G, and L h,j

15 A

C. Ranges, cooking appliances, laundry equipment or socket-outlets rated at more than 10 A for the connection thereof h

50% connected load 15 A 2.8 A per living unit

D. Fixed space heating or airconditioning equipment, saunas or socket-outlets rated at more than 10 A for the connection thereof h,k

75% connected load75% connected

load75% connected load

E. Instantaneous water heaters l

33.3% connected load 6 A per living unit100 A + 0.8 Aper living unit

F. Storage water heaters m

Full-load current 6 A per living unit100 A + 0.8 Aper living unit

g. Spa and swimming pool heaters 75% of the largest spa, plus 75% of the largest swimming pool, plus 25% of the remainder

TABlE C1 – MAXIMUM DEMAND – SINglE AND MUlTIPlE DOMESTIC ElECTRICAl INSTAllATIONS

All Demand calculations shown are based upon domestic home installations covered by AS/NZS 3000: 2007 – Appendix C / Table C1 Domestic Home Installations. For Commercial Installations please refer to AS/NZS 3000: 2007 – Appendix C / Table C2 Non-Domestic Installations.


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Of note in Table C1 is Clause 1/E that states “Instantaneous water heaters: 33.3% of connected load” – see below:

INSTANTANEOUS WATER HEATERS l

33.3% connected load

6 A per living unit

100 A + 0.8 A per living unit

The impact on the electrical supply requirement is significant from a “reduction in electric current demand” perspective. In direct relation to the CFEWH SERIES 1 TANDEM HWS Solution, where the worst case scenario would be the installation of the CFEWH SERIES 1-20 solution, the “After Diversity Demand” value would be:

CFEWH SERIES 1-20 Connected Load = 80AMPS 33.3% Connected Load = 26.6AMPS

In addition, the impact of CFEWH “optimised” energy on the reduction of energy usage can be as high as 50%, reducing the Connected Load to +/-13AMPS.

Noting Table C1/F that states Storage water heaters: Full-load current – see below:

STORAgE WATER HEATERS m

Full-load current

6 A per living unit

100 A + 0.8 A per living unit

The impact on the electrical supply requirement is significant from an “increase in electric current demand” perspective. In direct relation to a 4.8kW Centralised Storage-type HWS Solution, the “After Diversity Demand” value would be:

4.8kW Centralised Storage HWS = 20AMPS 100% Connected Load = 20AMPS

The combined Instantaneous Water Heater “After Diversity Factor calculation” combined with an “Optimised Hot Water Service Solution” delivers a very realistic Hot Water Service solution.

Reference Contact Details

AS/NZS 3498Lic: WMKA22136

Standards Australia

IEC 60335.2.35T120312_S

AS/NZS 60335.2.35A/13670EA

E1109-0066-1 C-Tick N29465

Patent Cooperation Treaty (PCT)

Patent Protected.

Trademarks Protected

All Demand calculations shown are based upon domestic home installations covered by AS/NZS 3000: 2007 – Appendix C / Table C1 Domestic Home Installations. For Commercial Installations please refer to AS/NZS 3000: 2007 – Appendix C / Table C2 Non-Domestic Installations.

For technical support or more information

phone 03 9681 7088

MicroHeat Technologies Pty ltdUnit 6, 38-42 Sabre Drive PORT MELBOURNE VIC 3207 AUSTRALIA www.microheat.com.au


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