Vision TZ58/1800-10 Installation, Operation and Maintenance Manual

Brand: Vision

Model: TZ58/1800-10

Type: Installation, Operation and Maintenance Manual

Vision Solar Systems

100 L Gravity Fed Type

Issue 2.0 Mar 2013

Vision Solar Systems

100 L Gravity Fed Type

Installation, Operation

And Maintenance Guide

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

! IMPORTANT NOTICE

Please read this manual immediately on receipt of the equipment, before unpacking and

installation. Failure to comply with these instructions can render warranties null and void.

Care for your equipment and safety

Read these instructions before preparing to install the solar water

heating system. The instructions contain information that will assist

you in your task, provide information about what is contained in the

packaging, and information about the water heater’s performance and

characteristics.

Position the system so that the Tubes are out of reach of children and

children’s play areas. If necessary, a guard can be purchased to protect

the tubes from objects directed at them.

Position the system and any overflow pipes will guide any runoff

water into a safe area. If this is not possible, then a gutter must be

fitted to guide any overflow water into a safe point of discharge

If animals, particularly monkeys are a menace in the area, then

additional protection measures will need to be taken to prevent

damage or malfunction of the system. This protection should prevent

access, but not affect the sun reaching the collector.

Do not touch the inside of the tubes, if they have been subjected to

solar irradiance, the inside can be extremely hot.

Do not fill the system with water if the tubes have been subjected to

solar irradiance, the sudden contraction with the cold water will result

in the tubes cracking

The main storage water tank must always be vented to the

atmosphere.

Vent pipes must be open to the atmosphere

Do not fit any pressure controlling devices on the overflow or vent

pipes.

Vent pipes must be open to the atmosphere

Only use elements and thermostats approved by the manufacturer.

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

The Electrical Element should be connected by a qualified electrician

registered with the Electrical Contractors Board. This will insure that a

correct and safe installation is completed.

Ensure that all electrical connections are kept dry and protected from

the ingress of water and moisture.

The installation should be performed or under the control of a

qualified person in terms of The National Building Regulations and

any additional regional requirements as set out by Local Building

Regulations

Try and use a plumber who is registered with the Plumbers

Registration Board (PIRB) AND who has completed the elective

course on Solar Installations, and who is familiar with the product.

The installation must comply with the National Building Regulations,

The National Water Regulations and the Local Water (Plumbing)

Regulations in the area where the installation takes place.

Avoid axial or twisting force on the pipes. Do not use a pipe wrench

on the pipe to tighten the connection. Always hold the pipe when

tightening the connection.

It is important to the operation of the system to use balanced pressure

to any mixing valves on the hot water outlet to prevent back feed into

the system.

We do not recommend connecting mixing valves to the system outlet.

While these systems contain no hazardous materials, it is always good

practice to recycle. Should you need further information, please

contact your local agent.

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

INDEX

Care for your equipment and safety

Unpacking

Reporting Problems with This Guide

For Further Information and Technical Assistance

Principal of Operation

Performance

Specifications

Installation

Using a timer on the Electrical Heating

Cleaning

Routine Inspection and Maintenance

Trouble Shooting

Warranty Policy

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

Unpacking

It is important when receiving the equipment that you confirm that all the components of the

system are received and are in good order. Listed below is a table of some of the most common

parts ordered with an indication of whether these parts are supplied as standard or as optional

equipment. Please check any additional parts against the original delivery note or invoice.

Description

Qty

Supplied

as Kit

Optional at

additional

cost

System Frame (Flat Roof or Pitch Roof as per Order)



Main Tank



Electric Element (Supplied fitted if ordered with Tank)



Thermostat (Supplied fitted if ordered with Tank)



Isolator Switch and Weatherproof Box



24 hour Timer with spring reserve



Reservoir Tank (with Ball Valve fitted)



58 x 2000 x 2 mm Vacuum Tubes



Cold Water Pipe Kit



Hot Water Pipe Kit



Overflow Pipe Kit



Drain Valve



2 x 4 Weatherproof Electrical Box with Isolator



Tempering Valve



Tube Guard (Expanded Metal cover for tubes)



Reporting Problems with This Guide

Please use the fax or email addresses below to report any problems you find in this

guide.

Enervision Technical Services

FAX: +27 11 395 4710

EMAIL: info@enervision.co.za

For Further Information and Technical Assistance

Enervision (Pty) Ltd recognizes the need to keep you informed about the availability of

current product information.

For up-to-date product information and a complete listing of sales offices, visit the

Enervision website at: http://www.enervision.co.za

For comprehensive product data sheets, Product Guides and application notes please

contact your local Enervision representative or email: info@enervision.co.za

For technical assistance, contact your local Enervision representative in the first instance,

alternatively phone 0861 111 270 or +27 11 395 3730 or email info@enervision.co.za

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

Principal of Operation

Construction

The system comprises an inner storage tank, an outer cladding and an insulation medium

between the two. A cistern tank with a ball or float valve is attached to the main tank and acts as

a control valve to keep the main tank full. The solar collector consists of vacuum tubes that collect

the energy from the sun, and via thermo siphon, will heat the water in the tank. The tank should

be fitted with a vent pipe connected to the side of the tank, and raised to above the level of the

vent on the cistern tank. This will ensure that the tank is not subjected to any pressure.

These solar water heating systems consist of four major parts as shown in the picture and

detailed below:

The Thermal Storage Tank

The thermal storage tank is a stainless steel tank constructed from 304 stainless steel material

and, being a low pressure tank, we can use a technology we term “no-weld”. This involves all

the pipe connections to the tank using a long life silicon grommet type seal and the end caps

using a pressed and rolled seal. This eliminates welding from the tank and increases the

longevity of the tank as any weld points can act as points where corrosion will start. The tank

holds the potable water, is maintained full of water by the cistern tank, and has the collector

tubes connected to it. Water is drawn from the tank by gravity feed. The tank must be located

above the water outlet, and the pressure of the water is determined by the height of the tank

above the water outlet.

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

The Collector

The collector consists of vacuum tubes that contain some of the thermal fluid (water) and are

connected into the tank via a silicon grommet type seal. The vacuum tubes are constructed from

two extremely strong Borosilicate glass tubes of different diameters and placed one inside the

other. At the one end the tubes are joined together and sealed and at the other end the inner tube

is supported. A vacuum is then drawn so that the space between them becomes a vacuum. The

vacuum prevents heat loss from the tubes (much like a thermos flask) and ensures that while the

inner tube can contain hot water the outer tube is cool to the touch.

In order to maintain the vacuum between the two glass layers a ‘barium getter’ is used (the same

as in television tubes). During manufacture of the vacuum tube the ‘getter’ is exposed to a high

temperature which causes the bottom of the tube to be coated with a layer of pure barium. The

barium layer actively absorbs any CO, CO², N², O², H²O and H² gasses from the vacuum tube

during storage and operation thus helping to maintain the vacuum. The barium layer also

provides a clear visual indicator of the vacuum status. It will turn white when the vacuum is lost.

The inner tube is coated with a special multi-layer coating forming a selective absorption layer

that assists with the collection of energy from the sun and transfers this energy into heat in the

water. The number of tubes used is chosen to cope with the volume of water in the tank which

needs to be heated on a standard solar day.

The Cistern or Reserve tank

The cistern or reserve tank is a small tank which feeds the main thermal tank. It contains a ball

valve which ensures that that the reserve tank is always filled to a certain level. If the level in the

main tank drops through the cooling (and reducing volume of the water) the ball valve will open

and top up the system. The ball valve is the only moving part in the complete system.

WARNING: Do not extend the pipe connecting the cistern tank to the main tank. This will

increase the pressure of the main tank which is designed to be vented to the atmosphere at a

height of less than 1m from the main tank.

The Backup Heating

In any heating system the time that hot water is not available must be limited. On cloudy days

the solar energy able to be harvested could be limited and, though there is a degree of energy

available, it may not be sufficient to heat the amount of water required. In this system a

thermostatically controlled backup electrical heating element is used to heat the water in the

tank.

NOTE: The element is supplied as an optional extra, and if required, should be included in your

order to your supplier.

Operation

Collecting the energy from the sun

As the sun’s rays fall on the collector or collector tubes the irradiance is transformed from the

light energy to heat energy in the water in the tubes. The coating used on the inside assists in

transforming the ultraviolet light from the sun into heat inside the tubes. This aids in collecting

some solar (UV light energy) on cloudy days.

The heated water inside the tube expands and become more buoyant. It moves up the collector

tube and eventually enters the tank, and it is replaced by colder water from the tank which is, in

turn, heated by the sun’s energy. This process, known as thermo-siphon, happens continuously

while the solar energy falls on the collector.

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Maintaining the energy in the thermal storage tank

The tank is constructed of double shell much like the tubes. The inner shell is stainless steel and

contains all the connections and seals for the pipes and tubes. This tank is open to the atmosphere and

is not under any pressure. The outer tank or shell is a thin sheet that protects the system and between

the two layers is a thick layer of thermal insulation that restricts the loss of heat from the water in the

inner tank. Using a low pressure tank to contain the thermal mass of water has its advantages. Firstly,

it limits the maximum temperature of the water in the tank as the water cannot rise above 100ºC – the

point at which water boils at sea level. Secondly, by not having a tank of hot water under pressure,

there is no need for management to ensure the safety of people, animals and possessions near the

tank.

Supplying the Hot Water

Water is supplied to the plumbing by gravity feed. This requires that the tank is mounted above the

water outlet to ensure a supply of water. The higher the tank is mounted above the water outlet, the

greater the pressure of the water at the outlet. Note that the tank is designed for zero pressure, to

extend the height of the cistern would place the tank under pressure, and this will affect the safe

operation of the system, and can be harmful to persons and property.

The Backup Heating

The need for backup heating is twofold – firstly, to compensate when there is little or no sunshine,

and, secondly, when water usage exceeds the daily solar heating capacity. In these situations the

backup element acts as a substitute heat source to the sun. It is a good practice to fit the timer to the

supply feed for the element. With electricity conservation being the objective, a timer with a

reasonable reserve (time it will continue to maintain time without the mains available) and the ability

to set up exclusion zones should be installed. This will prevent the use of the electrical element during

peak electricity usage period and also during the sun’s normal heating time.

Considerations

There are some considerations to take into account in a system like this as the performance of the

system differs to that of a normal hot water system.

1) The supply of water is via a gravity feed. Do not expect high pressures from the system. Flow

rates will depend on the height of the tank above the water outlet, and the restriction of the

pipe work to the water outlet.

2) The temperature of the water is dependent on the solar energy collected, and the amount of

water used. On sunny days with little water usage, the temperature can very high, and on

cloudy days with lots of water used, you can run out of hot water.

3) As the hot water is drawn from the system the water in the tank cools. This means that the

water temperature tapers off as the water is used. In other words, initially the water

temperature may be 65ºC, after half the water is used it may drop to 55ºC and at the end it

may be as low as 40ºC. This means you will initially use a low amount of hot water and mix

with cold water to get the water to the desired temperature and at the end you may be using

mostly hot water with very little cold water mixed in.

Safety and Operation

There are certain great safety features in this type of system;

1) The tank of hot water is at low pressure so the water cannot be superheated under pressure

and will never exceed boiling point. If left unused for an extended period of time the excess

solar energy collected each day will boil out into the cistern tank and, at worst, some water

can be lost through the overflow. This provides inherent safety of overheating and possible

bursting of the tank.

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Issue 2.0 Mar 2013

2) The tubes are cool on the outside; consequently there is no danger of being burnt

should they be touched.

3) No pressure and temperature relief valve is needed provided that the system is

correctly installed, with the vent pipes not extended more than 1 meter above the main

tank.

On the operational side there are also some great features;

1) The ball valve is the only moving part. High quality brass and stainless steel valves are

used to ensure durability and consistent operation.

2) The system works naturally so it will not need any power to control or manage the hot

water. Even overheating and freezing of the main tank parts are inherently controlled.

3) Inherently freeze resistant with the water in the main tank. (Excluding connecting pipe

work)

4) Inherently protected against overheating by the low pressure vented tank design and

the latent heat absorbed by boiling water.

5) No glycol or sacrificial anode maintenance required.

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Performance

The output of the solar water will depend on the amount of solar irradiation that reaches the collector

throughout the day. On a good day, with 6-7 hours of sunlight, the glass tubes will collect enough

energy to heat the water up to 60ºC - 70ºC. You may even spot steam coming from the vent pipe as the

water reaches boiling point. This is quite normal if you have not been using water from the system. By

setting the tilt less than the latitude the system will work better in summer and using a tilt of more

than latitude will improve the performance in winter.

By facing the system a few degrees east of true north the water will heat earlier in the day and,

similarly, a little more west of north will mean the water will heat later in the day.

Shown below is the average solar irradiance for various cities in South Africa for collectors positioned

at true north and a tilt equal to the latitude:

Based on the above average solar irradiance, the average daily temperature rise of the thermal storage

water would be as shown in the table below. Note that these are average figures and, on any one day,

depending on the cloud cover and temperature, different results will be obtained:

Note that one needs to consider the amount of hot water drawn from the tank each day (the energy

used) and the residual temperature each day to determine what the actual storage tank temperature

will be, and what the total available hot water from solar heating only will be.

Based on at least this hot water input being used every day, in other words, that tank is in

equilibrium, without boiling, or running out of hot water (the balance coming from electrical heating

if this is required), the average daily saving in electricity is shown in the table below:

Solar Irradiance MJ/m²/day (figures from NASA 22 year average)

Area

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Johannesburg

21.5

21.0

20.7

20.5

20.6

20.3

21.5

23.1

23.5

21.3

21.4

21.5

Cape Town

26.2

25.6

23.5

19.9

16.0

15.0

15.5

17.2

20.5

23.4

25.2

25.6

Durban

18.6

19.1

19.0

19.1

18.6

18.1

18.8

19.8

19.2

17.3

17.7

18.4

Port Elizabeth

22.1

20.9

19.4

18.1

16.7

15.9

16.9

17.9

19.4

19.7

21.0

22.1

East London

21.0

20.3

19.2

18.6

17.9

17.0

17.6

19.1

20.2

19.4

20.3

21.3

Bloemfontein

23.9

22.8

21.6

29.8

20.1

19.4

20.4

22.9

23.3

23.0

23.4

24.2

Expected Average Temperature Rise of water in the Storage Tank from Solar Only

Area

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Johannesburg

17.0

16.6

16.3

16.2

16.3

16.1

16.9

18.7

18.5

16.8

16.9

Cape Town

20.5

20.0

18.4

15.8

12.8

12.0

12.4

13.7

16.2

18.3

19.7

20.0

Durban

14.8

15.1

15.0

15.1

14.7

14.4

14.9

15.6

15.2

13.8

14.1

14.6

Port Elizabeth

17.4

16.5

15.4

14.4

13.3

12.7

13.5

14.2

15.3

15.5

16.6

17.4

East London

16.6

16.1

15.2

14.7

14.3

13.5

14.0

15.1

15.9

15.3

16.0

16.8

Bloemfontein

18.8

17.9

17.0

16.4

15.9

15.3

16.1

18.0

18.3

18.1

18.4

18.9

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Issue 2.0 Mar 2013

Always remember that the solar performance will depend on the amount of sun on the collector.

Cloudy weather will decrease performance and reduce the amount of energy harvested from the

sun. In addition, shade from trees and other objects during the day will mean that less solar

energy is harvested. There is a backup element that can be fitted to the system to cope with bad

weather and lower solar irradiation and also for abnormally high hot water demand. The backup

element is thermostatically controlled and is normally used in conjunction with a timer so that

the use of electrical energy can be controlled and used only when there is no solar harvesting

likely to take place.

In order to heat the water in the tank with the electrical element some time is needed to attain the

required temperature. Shown below is the graph of the time taken to heat water from 20ºC to

70ºC.

If the tank is at a higher temperature the time for 20ºC to the starting tank temperature can be

subtracted from the full reheating time. Note that you will need to take into account the timer

exclusion zones if these are active in the electrical element reheat cycle or alternatively put the

timer into the bypass mode.

20.0

30.0

40.0

50.0

60.0

70.0

80.0

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

Water Temperature in the Tank

Time in Hours

Reheat Time with Electric Element

1.5 kW Element

Average Energy Saving per Day (kWh)

Area

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Johannesburg

4.7

4.6

4.5

4.7

5.2

5.1

4.7

Cape Town

5.7

5.6

5.1

4.4

3.6

3.3

3.5

3.8

4.5

5.1

5.5

5.6

Durban

4.1

4.2

4.1

4.0

4.1

4.3

4.2

3.8

3.9

4.1

Port Elizabeth

4.8

4.6

4.3

4.0

3.7

3.5

3.7

3.9

4.3

4.6

4.8

East London

4.6

4.5

4.2

4.1

4.0

3.8

3.9

4.2

4.4

4.3

4.5

4.7

Bloemfontein

5.2

5.0

4.7

4.6

4.4

4.3

4.5

5.0

5.1

5.0

5.1

5.3

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Issue 2.0 Mar 2013

Specifications

Description

Specification

System Type

TZ58/1800-10

Storage Tank

Capacity

100ℓ

Inner Tank Material

0.6mm US304

Inner Tank Diameter

375mm

Insulation Material

Polyurethane

Insulation Thickness

50mm

Insulation Density

36kg/m²

Outer Tank Material Optional

Zinc coated 0.4mm Painted

Steel

Outer Tank Diameter

475mm

Optimal Flow Rate

7ℓ/min

Fluid Type

Water

Tank Maximum Pressure

50kPA

Collector Tubes

Outer Tube Diameter

58mm

Material

Lead Free Glass

Thickness

2mm

Inner Tube Diameter

47mm

Material

Lead Free Glass

Coating

Multilayer SS-C/Cu

Aperture Area

0.95m²

Absorber Area

1.76m²

Performance

Estimated Life Span

10 years

System Output (16MJ)

12.89 MJ

Note: In order to allow for continuous improvement, Enervision reserves the right to update and

change specifications without prior notice E&OE.

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Installation

Tools Required

It is essential that the installation is completed by an accredited plumber who has been

trained in solar water installations and has completed an installation training course on this

type of solar system.

In order to complete the installation successfully the following tools are recommended:

 3m Ladder (two recommended)

 Ropes and slings

 10mm Ring Flat Spanner

 13mm Ring Flat Spanner

 19mm Flat Spanner

 22mm Flat Spanner

 Small Flat Screw Driver

 Adjustable Spanner

 Copper Pipe Cutter

 Gas Solder Unit

 Solder Flux

 Solder

System Location

The location of the solar water heater should be on an even surface facing true north. A variation

of 20 degrees either side of true north will have a negligible effect on the overall performance.

The collector must be in full sun, free from shadows, between the hours of 9am to 4pm

throughout all the seasons.

The tilt angle recommended for the collector is latitude plus 15 degrees. Increasing the tilt angle

will improve the winter performance while decreasing the tilt angle will increase summer

performance. The lower the latitude, the more critical the tilt angle will be to the overall system

performance.

Cloud cover will affect performance, if cloud is predominantly in the mornings, then try to face

the solar collector more west of north, and if cloud cover is in the afternoon, then facing the

collector more east of north will assist the performance. The Solar input as indicated on page 11

will provide an indication of the worst performing months of the year. In winter rainfall areas it

is recommended that the tilt angle is increased to improve winter performance.

Tips on finding True North

Satellite dishes point to PAS7/10. This is positioned 68 degrees East of North.

Some GPS systems will have a compass. Please confirm the accuracy of this before using it as

they will sometimes require movement to determine direction.

Use of a sundial type compass with a vertical shadow and a time of day can also be used to find

True North.

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

Frame Assembly

Assemble the frame as indicated in the sketch below:

Ensure that all the bolts and nuts are tight.

Securing the System

Ensure that the intended location is sufficient to support the full weight the system when it is filled

with water, and that there will be negligible sag that can damage rigid materials such as tiles if there

is any movement.

The rear legs are attached to a spreader beam to spread the weight of the water in the tank across the

roof area. The spreader contains holes that allow the frame to be secured to the structure on which it is

mounted. Use suitable bolts and nuts to secure the feet to the structure. Ensure that all feet are secured

to a ridged part of the mounting structure. Any penetration of the roof structure must be suitably

repaired to maintain the waterproofing.

Failing to adequately secure the system to the structure can result in the frame flexing when subjected

to high winds. This can cause excessive stress on the frame, tubes and tank and can result in the tubes

fracturing.

Where extremely high winds are experienced, additional care must be taken in

securing the system and additional stainless steel guys may also be required to ensure

that the system is securely mounted.

Mounting the Main Tank and Reservoir Tank

Always secure the pipe connection to the tank with a spanner to prevent any axial or

twisting forces on the pipe. Use the mounting support bracket for the reservoir tank

and adjust the feet to ensure that there is no axial force on the pipe connection.

Remove the thread protection caps and nuts from the tank mountings.

Lift the main tank and position it on the frame curved tank mounting brackets, ensuring that

the bolts are not pushed into the tank. The tube holes should be pointing towards the front of

the frame and the pipe connections should be on the right hand side when looking at the

collector from the front. Put the tank bolts into the slotted holes in the tank mounting bracket

and lightly tighten the nuts onto the bolts.

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

Rotate the tank so that the bolts are approximately in the middle of the slots.

Place the reservoir tank mounting bracket over the pipe inlet on the right hand side of the tank

near the pipe connections. Screw on the reservoir tank and turn until the thread is tight. You

will need to use a spanner to hold the pipe from the main tank. Once the tank is tight use the

plastic bolts on the bracket to support the tank and ensure that there is no axial force on the

pipe connection and ensure that there is no movement on the mountings.

Connect the drain valve that complies with SANS 1848-53 to the bottom outlet on the tank.

Connect the cold water pipe, as shown, to the reservoir tank. Ensure that the shutoff valve is

fitted to this pipe.

Connect the hot water pipe to the hot water output at the bottom of the tank.

Connect the overflow pipe to the reservoir tank as shown in the schematic.

Connect an additional overflow pipe to the side of the main tank as shown in the schematic.

For all these connections, again take care to support the pipe connection to the tank in order to

ensure that no axial or twisting force is applied to the tank pipes.

Connect the cold water shutoff valve to the cold water supply.

Test all connections for leaks. The shutoff valve on the cold water feed can be used to control

the water flow.

Enervision recommends that the hot water pipe from the geyser to the point of use does

not exceed 10m and that the pipe is lagged along the whole length.

In frost areas, cold water pipe and overflow pipes must be suitably lagged to prevent

freezing.

Additional

Overflow pipe

Cold Water

Supply

Hot Water

Output

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

Inserting the Vacuum Tubes

Do not fill any tubes with cold water if they have been exposed

to the sun. The sudden contraction will cause them to fracture.

Keep the tubes covered and in the packaging when not preparing them for insertion into the tank.

Spray or dip the open end of the tube in a dilute soapy non-toxic water solution.

Pull the dust cover over the tube to about 150mm from the open end of the tube. Ensure that it is

placed the correct way round with the bevelled side away from the open end.

If necessary, re-wet the open end of the tube.

Insert the tube into the opening of the tank, working from the centre to the outside.

The tubes should be inserted well into the tank and then pulled back into the boot on the back box

mounted on the stand. Once the tube has been installed in the tank, move the dust cover into

position.

It is recommended that the supply and outlet pipework is completed before the tubes are incerted.

This will allow for a slow trickle water into the main tank to fill the tubes as the tube is inserted fill

with water. Alternatively cover the tubes with an opaque cover, such as canvas cloth or the

cardboard box until the system is filled.

Adequate precautions must be taken to prevent the tubes from heating in the sun. If this is not

possible, wait until the early hours of the morning, before the sun has had time to heat the tubes, to

fill the system with water.

Fitting the Electric Element

Any electrical work done on the system should be done by a

qualified electrician. There are various safety and legal

requirements that must be complied with.

In order to comply with the safety requirements, only Enervision Approved elements and thermostats may be

used in the system. Do Not fit an electric element without a thermostat.

If the system was ordered with an electric element, the element will be pre-fitted to the system.

The Code of Practice for electrical installations requires that a two pole isolator switch is fitted to the

supply to the element.

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

Using a timer on the Electrical Heating (Optional)

Fitting a Timer

Enervision recommends that a timer is fitted to control the supply to the element. This should

exclude the peak demand periods in the morning between 7am and 10am, in the evening between

6pm and 9pm, and also between 10am and 3pm when normal solar water heating is taking place.

(On cloudy days this time zone can be overridden if hot water is required in the early evening.)

MTD 2 Type Timer

This timer is a 24 hour timer with 15 minute programme intervals and a 7 day reserve.

Connect the electrical circuit as shown in the diagram below.

Programming the Timer

Each toggle in the programming dial corresponds to a period of 15 minutes. When the toggle is

in the right hand position, the element is on and when the toggle is ion the left hand position

then the element is off. To set the timer for Eskom DSM, switch all toggles over to the right.

Turn the dial and set the toggles from 7am to 3pm to the left position. Repeat the above for the

times from 6pm to 9pm.

Turn the dial so that the current time corresponds with the actual time. Note that the timer has

a 100 hour reserve. If the power is off for more than 100 hours the time will need to be reset.

Note: there is a manual override on the timer which allows the timer function to be overridden.

For normal timer operation the override should be in the upper position and to override must

be moved down.

The MTD8 or the TDDGT Type Timer

This timer is a 7 day timer with 1 minute programme intervals and a 15 day reserve.

Connect the electrical circuit as shown on the diagram below:

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013

Programming the timer

Setting the time

 If there is no display, press and hold the RESET button for a few seconds

 Press and hold down the clock button while pressing the D+ button to the desired day of the

week.

 Press and hold down the clock button while pressing the H+ button to the desired hour.

 Press and hold down the clock button while pressing the M+ button to the desired minutes.

 Release the clock button when the time and day is set.

Setting the Time Zones

 Press P, Display will show the Time Zone 1 On time.

 Use the H+ to set the hour.

 Use the M+ to set the minutes.

 Use the D+ to set the day of the week. Enervision recommends MTWTFSS as default. (cycles

MTWTFSS, MTWTFS, MTWTF, SS, MTW, TFS, MWF, TTS, M, T, W, T, F, S, S)

 Press the P again. Display will show Time Zone 1 OFF time.

 Press the H+ to set the hour.

 Use the M+ to set the minutes.

 Use the D+ to set the day of the week. Enervision recommends MTWTFSS as default.

 Press P again to go to Next Zone and continue from the top, or Press Clock to stop setting

Time zones.

There are a possible 16 time Zones that can be set.

Vision Solar Systems - 100 L Gravity Fed Type

Issue 2.0 Mar 2013



First Filling with Water and Commissioning

Do not fill any tubes with cold water if they have been

exposed to the sun. The sudden contraction will cause them

to fracture.

Two methods can be used for the first filling of the tank.

Method 1 – Filling while inserting the tubes;

In this method the installation of the system needs to be complete with all the plumbing connections

made except for the vacuum tubes.

 Open the inlet supply valve and allow the water to fill the tank up to the holes for the

vacuum tubes. Adjust the water so that it just trickles out of the tube holes.

 Check that the water contains no gritty deposits. (If this is the case, Enervision recommends

the fitting of a filter trap and implementation of a regular maintenance procedure to clean

the filters).

 Prepare the first tube for fitting with the dust cover and soapy lubrication.

 Insert the tube into the hole and then secure into the tailstock.

 Continue with the next tube, all the time ensuring that the tubes immediately start filling

with water once they are fitted.

 Once all the tubes are fitted open the inlet valve completely and allow the tank to fill via the

ball valve and reservoir tank.

 Check that the ball valve closes once the tank is full and that no water is discharged from the

overflow.

 Check all installed pipework to ensure that there are no leaks.

 Open the drain and drain off 10 litres of water into a clean bucket. Check for any gritty

deposits and that the ball valve closes again. Repeat if necessary.

 Switch timer into the override mode and switch on the isolator.

 Monitor the current on the electrical element with a tong tester. (Do not confirm with

voltage measurements.).

 The system is now ready for use and will require time to heat.

 See performance information on page 11 to gauge the time it will take to heat the water

sufficiently.

Method 2 – Filling with the tubes fitted

In this method the installation of the system is complete including the vacuum tubes.

 If the tubes have been exposed to the sun for an extended period, wait until the early

morning before filling the system.

 If the tubes are fitted in the evening, less than 1 hour from sunset, the system can be filled.

 Open the inlet valve completely and allow the tank to fill via the ball valve and the reservoir

tank.

 Check that the ball valve closes once the tank is full and no water is discharged from the

overflow.

 Check all installed pipe work to ensure that there are no leaks.

 Open the drain and drain off 10 litres of water into a clean bucket. Check for any gritty

deposits and that the ball valve closes again. Repeat if necessary.

 Switch timer into the override mode and switch on the isolator.

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Vision TZ58/1800-10 Installation, Operation and Maintenance Manual

Vision TZ58/1800-10 Installation, Operation and Maintenance Manual

Vision TZ58/1800-10 Installation, Operation and Maintenance Manual

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