Ariston STI 125 INDIRECT, STD 125 DIRECT, STD 150 DIRECT, STD 210 DIRECT, STI 150 INDIRECT User Manual

UNVENTED CYLINDER

RANGE

UNVENTED WATER STORAGE CYLINDER

No longer than every 12 months, the magnesium anti-corrosion

anodes should be checked by your service engineer/installer.

Installation and Users Guide

IMPORTANT

Please read these instructions carefully

before installing the cylinder.

Failure to do so may invalidate the Warranty

WATER BYELAWS

These bye-laws ensure a good supply of wholesome water, and that only approved materials, pipes and fittings are used to
convey water.

BUILDING REGULATIONS

These are a statutory document and take priority over all other regulations and recommendations. The installation of an
unvented hot water storage cylinder is classified as a "Controlled Service" and Regulation G3 applies. To meet the
requirements of the Regulation, installation of an unvented system should be undertaken by a "competent installer".

All installations of unvented hot water storage systems having a capacity of more than 15 litres should be notified to the
relevant Local Authority by means of building notice or by the submission of full plans. It is important to note that it is a
criminal offense to install an unvented hot water storage system without notifying the Local Authority.

DELIVERY

The range is available with the following options;

The wall-hung range (50, 75, 100 litre models), which are supplied as the following;

One large box containing;

1) The unit with factory fitted Temperature & Pressure Relief Valve and Immersion Heater.

One small box containing;

1) Unvented control pack (Expansion vessel, 2 piece Cold Water Combination Valve, Tun Dish).

The Ariston Contract and the Ariston Comfort (Indirect only) floor-standing range (125, 150, 200 litre models).

The Contract is supplied with the following;

One large box containing;

1) The unit with factory fitted Temperature & Pressure Relief Valve.

2) Immersion Heater(s) (not fitted).

3) Cylinder Thermostat (Indirect only, not fitted).

4) Feet x 3.

One small box containing;

1) Unvented control pack (Expansion vessel, 2 piece Cold Water Combination Valve, Tun Dish, Drain Cock and Motorised
Valve (Indirect only).

- 3 -

Hot and cold water are both drawn off the same source of supply. Remember, there will not be a storage tank to help
compensate for variations in the demand on the system.

A minimum pressure of approximately 1.5 bar and 20 litres per minute is required for satisfactory operation. 85% of UK
dwellings have a mains pressure above 2.0 bar.

THE MAINS WATER SUPPLY MUST NOT EXCEED 12 BAR

SITING AND FIXING

The cylinder may be installed at any convenient position, as it is connected to the mains cold water supply, it is equally
effective on any floor.

However, do not install the unit in premises which may be subject to freezing. Ensure that the floor load bearing strength is
adequate to take the weight of the cylinder when full of water (see table 1).

The ST50, ST80 and ST100 models are wall mounted. All other models are free standing. These are supplied with feet
which are attached to the heater via self tapping screws which are also supplied. All units must be installed in the
VERTICAL POSITION.

For maintenance purposes leave at least 500 mm free space in front of the unit, for access to electrical components,
immersion heater(s) and magnesium anodes.

CONNECTION OF MAINS WATER SUPPLY
For Contract & Comfort models:
On the front of the unit there is a label to identify the connection ports. Please check this before making any connection
to the unit.

For units up to 300 litres it is recommended that all mains cold water supply pipe work is a minimum of 22mm, with the
exception of model ST50 where 15mm can be used. For 500 litre models the supply should be 28mm. An Isolating Valve
should be installed between the cold water supply and the cylinder for servicing. ALL PIPEWORK MUST BE FLUSHED TO

AVOID DAMAGE TO THE CONTROL VALVES.

Please refer to figs. 1, 2 , 3, 3, 3, 3, 3 for a suggested installation layout.

COLD WATER COMBINATION VALVE

The Cold Water Combination Valve can be connected either close by the unit or alternatively it may be installed in a remote
position from the unit as there is no requirement to site it in close proximity to the cylinder. This allows a flexible and
convenient installation. However, it is important to note allowances for the discharge pipe work from the Expansion Relief
Valve must be accounted for.

A Balancing Port is supplied on the 22mm (for units above 50 litres) valve allowing balanced cold water supply to the rest of
the building giving excellent results with mixer and shower valves. If the facility is not needed a plug is supplied. Refer to fig.
4

Although this facility is not built into the 15mm valve (supplied with Contract ST50), a Tee Piece may be inserted between
the two components giving the same results. Refer to fig. 5

CONNECTION TO SERVICES

Again it is recommended that a 22mm pipe run should supply the outlets throughout the building, especially to baths and
showers. Short runs of 15mm pipe may be used to connect basins and sinks.

- 5 -

The Comfort is supplied with the following;

One large box containing;

1) The unit with factory fitted Temperature & Pressure Relief Valve.

2) Factory fitted Immersion Heater (Dry pocket).

3) Factory fitted Cylinder Thermostat.

4) Feet x 3.

One small box containing;

1) Unvented control pack (Expansion vessel, 2 piece Cold Water Combination Valve, Tun Dish, Drain Cock and Motorised
Valve).

The high capacity floor-standing range (300, 500 litre models), which are supplied as the following;

One large box containing;

1) The unit

2) Factory fitted Temperature & Pressure Relief Valve (300 litre models only).

3) Factory fitted Immersion Heater(s)

4) Factory fitted Cylinder Thermostat.

5) Feet x 3.

One small box containing;

1) Unvented control pack (Expansion vessel, 2 piece Cold Water Combination Valve, Tun Dish, Drain Cock and Motorised
Valve) (500 litre model 1" Temperature & Pressure Relief Valve).

HOW THE HEATER WORKS

The Immersion Heater(s) are connected through a thermostat which senses the water temperature. The operating
temperature can be pre-set by adjusting the spindle in the head of the thermostat. In addition to the thermostat there is a
Thermal Cut-out incorporated if the thermostat fails and the water temperature rises too high. Once the cut-out operates it
can only be re-set manually after the fault has been rectified.

Indirect models have dual thermal controls. In addition to the above there is a separate Cylinder Thermostat and Thermal
Cut-out for controlling the indirect circuit. Again the Thermal Cut-out operates if the Cylinder Thermostat fails, by
disconnecting the live feed (call for hot water) from the programmer.

Floor-standing models have Magnesium Anodes provided to prevent corrosion of the water cylinder tank. Wall-hung units
have a single Magnesium Anode.

The factory fitted Temperature & Pressure Relief Valve at the top of the cylinder is a safety device to back-up the
Thermostat(s) and Thermal Cut-out(s). It works by sensing an excess in water temperature or pressure and releasing the
hot water into a Discharge Tundish and drain.

The cylinder will only work in the vertical position. The inlet pipe needs to deliver cold water to the bottom of the tank. When
water is heated it expands. To accommodate this increase in volume an Expansion Vessel is provided. A Cold Water
Combination Valve is also provided in two pieces, loose jointed for ease of installation. These comprise a Combined Line
Strainer/Pressure Reducing Valve and Core Non Return Valve/Expansion Relief Valve.

The Strainer prevents any debris entering the other controls. The Pressure Reducer ensures the correct operation of the
Expansion Vessel, and prevents any damage to the control valves through too great a pressure.

The Non-Return Valve ensures the water expansion is forced into the Expansion Vessel and prevents contamination of the
mains cold water supply. The Expansion Relief Valve will discharge expanded water to the Discharge Tundish if the
Expansion Vessel fails.

COLD WATER SUPPLY

It is important to ensure that the cold water main is capable of supplying the increased demand which will be imposed on it.

- 4 -

AB

CD

ELECTRICAL

The electrical installation must be in accordance with the current I.E.E. wiring regulations.

FITTING IMMERSION HEATER(S) (CONTRACT RANGE ONLY)

These are supplied but not fitted with the Ariston Contract range. A Sealing Gasket is supplied with each element and must
be used to ensure a correct seal. Care must be taken not to cross thread the Immersion Heater(s) when fitting. Each
Immersion Heater is supplied with a Regulation Thermostat and manual reset Thermal Cut-out. This will activate if the
Regulation Thermostat fails. Under no circumstances should this be bypassed.

Although the Immersion Heaters are a standard 21/4” thread, they must not be substituted with anything but an
original Ariston spare part.

DIRECT SYSTEMS

A mains supply of 240V, 3kW (13 amps) is required. Heat resistant cable, round 3 or 4 core 2.5mm2 (to BS6141 table 8)
must be used to connect the electrical supply through the Economy 7 time control switch using either system ‘A’ or ‘B’ as
illustrated in fig. 8.

Should the Economy 7 system not to be used, a separate 13 amp supply to each element will be required. Through a
double pole fused isolating switch having a contact gap of at least 3mm on each pole. Make the connection(s) to the
Immersion Heater(s) as per figs. 9, 10. For 500 litre models consult the wiring diagram on the reverse of the inspection
panel.

The Thermostat(s) on the Immersion Heater(s) should be adjusted to trip at 60°C. This is the ideal temperature to prolong
element life in hard water areas. Scale on the sheath builds up more rapidly at temperatures above this causing the element
to overheat and premature failure can occur. Higher temperatures without additional controls would result in scalding.

In addition to the thermostat the Thermal Cut-out will switch power off to the element should the thermostat malfunction,
causing an excessive rise in water temperature. The Thermal Cut-out can be reset manually after the fault has been
corrected.

INDIRECT SYSTEMS

Again for models up to 300 litres a mains supply of 240v, 3kW (13 amps) will be required for the direct Immersion Heater.
Heat resistant cable, round 3 core 2.5mm² (to BS) must be used. For 500 litre models consult the wiring diagram on the
reverse of the inspection panel.
For indirect controls a 240V, 3amp supply is required.
On Comfort models the Indirect thermostat is factory fitted, for Contract models it is necessary to fit the thermostat using
P.T.F.E Tape (Please consult the label on the face of the unit for the correct location in both cases).

The cables must be clamped in position (as previously stated) and the control thermostat should be set at 60°C for the
reasons above. In addition to the thermostat there is a Thermal High Temperature Cut Out should the thermostat fail. Refer
to figs. 11 & 12 for full wiring instructions.

WARNING : THIS APPLIANCE MUST BE EARTHED.

The earth continuity conductor of the electrical installation must be effectively connected to all exposed parts of other
appliances and services in the room in which the water heater is to be installed, conformity with the I.E.E. wiring regulations.

NOTE : Do not switch on the Immersion Heater or fire the boiler until the water heater is full of water.

COMMISSIONING

Check for obvious signs of damage to the cylinder and controls and also that the controls fitted correspond with the
reference quoted in these instructions.

Ensure that the Drain Cock at the base of the water heater is closed before commencing.

1) Open all outlet taps.

2) Turn on mains water supply and allow the water heater to fill.

- 7 -

SECONDARY RETURN

On Floor-standing models a Secondary Return may be fitted. On Contract and Comfort models via the special port on the
side of the cylinder (consult the label on the face of the unit for the correct location), for 300 and 500 litre models refer to fig.

6. A Non Return Valve (not supplied) must be fitted to prevent back flow and a Bronze Pump will be needed in conjunction
with a Pipe Thermostat to circulate the hot water (both not supplied).

DISCHARGE PIPEWORK

1) The Tundish must be vertical and fitted within 500mm of the Temperature & Pressure Relief Valve and must be located
with the cylinder. The Tundish must also be in a position visible to the occupants, and positioned away from any electrical
devices. The discharge pipe from the tundish should terminate in a safe place where there is no risk to persons in the
vicinity of the discharge and to be of metal.

2) Discharge pipes from the Temperature & Pressure Relief and Expansion relief valve may be joined together.

3) The pipe diameter must be at least one pipe size larger than the nominal outlet size of the safety device unless it's total
equivalent hydraulic resistance exceeds that of a straight pipe 9m long.

I.e. Discharge pipes between 9m and 18m equivalent resistance length should be at least 2 sizes larger than the nominal
outlet size of the safety device. Between 18m and 27m at least 3 larger, and so on.
Bends must be taken into account in calculating the flow resistance.
See fig. 7 and Table 2.

4) The discharge pipe must have a vertical section of pipe at least 300m in length, below the Tundish before any elbows or
bends in the pipework.

5) The discharge pipe must be installed with a continuous fall.

6) The discharge must be visible at both the Tundish and the final point of discharge, but where this is not possible or
practically difficult; there should be clear visibility at one or other of these locations. Examples of acceptance are:

i) Ideally below a fixed grating and above the water seal in a trapped gully.
ii) Downward discharges at a low level; i.e. up to 100mm above external surfaces such as car parks,

hard standings, grassed areas etc. These are acceptable providing that where children may play or
otherwise come into contact with discharges, a wire cage or similar guard is positioned to prevent
contact, whilst maintaining visibility.

iii) Discharges at high level; I.e. into a metal hopper and metal down pipe with the end of the discharge

pipe clearly visible (Tundish visible or not). Or onto a roof capable of withstanding high temperature
discharges of water 3m from any plastic guttering systems that would such a discharge (Tundish
visible).

iv) Where a single pipe serves a number of discharges, such as in blocks of flats, the number served

should be limited to not more than 6 systems so that any installation can be traced reasonably easily.
The single common discharge pipe should be at least one pipe size large than the largest individual
discharge pipe to be connected. If unvented hot water storage systems are installed where
discharges from safety devices may not be apparent I.e. in dwellings occupied by the blind, infirm or
disabled people, consideration should be given to the installation of an electronically operated device
to warn when discharge takes place. Note: The discharge will consist of scalding water and steam.
Asphalt, roofing felt and non-metallic rainwater goods may be damaged by such discharges.

WARNINGS

The outlet from the Temperature & Pressure Relief Valve must not be used for any other purpose. This also applies to the
Expansion Relief Valve. No other valve is to be fitted between the Cold Water Combination Valve and the cylinder.

The Temperature & Pressure Relief Valve must not be removed in any circumstances. Any of the above will totally
invalidate the warranty.

- 6 -

FAULT POSSIBLE CAUSES REMEDY

1) Mains Cold Water Check and open Isolating
supply shut off and/or Stop Valve. Check

water, Local Water Authority

NO HOT WATER 2) Line Strainer Turn off mains water supply,
FLOW blocked remove Line Strainer and

clean

3) Cold Water Check direction of flow
Combination valve arrows on valve, refit in
fitted incorrectly correct position if necessary

1) Low Mains Water Check pressure, consult
Pressure Local Water Authority if

necessary

REDUCED FLOW 2) Line Strainer Turn off mains water supply,
RATE partially blocked remove Line Strainer and

clean

3) Size of Service Increase to size stated on
Pipe too small page 4

1) Direct Immersion Check Immersion Heater,
Heater is not switch on if necessary
switched on

2) Direct Thermal Test Thermostat operation
Cut-Out has and wiring, if faulty,
operated correct/replace. Reset Cut-Out

WATER FROM 3) Boiler Programmer Check switch on Domestic
HOT TAPS set to Central Hot Water if necessary
IS COLD Heating only

(Indirect models)

4) Boiler is not Check boiler operation, if
functioning fault suspected consult
(Indirect models) Manufacturer's Instructions

5) Indirect Thermal Test Thermostat operation
Cut-Out has and wiring, if faulty,
operated correct/replace. Reset

Cut-Out

6) Motorised valve Check wiring and operation of
jammed or not Motorised Valve correct/
wired correctly replace as necessary
(Indirect models)

DISCHARGE FROM 1) Pressure above 7 Shut down boiler or immersion
PRESSURE/ bar, failure of heater. Check pressure
TEMPERATURE Pressure Reducing Reducing Valve and Thermal
RELIEF VALVE Valve. Temperature Controls. Replace if

above 90 C failure necessary
of thermal control

DISCHARGE FROM 1) Continually. Check pressure from valve.
EXPANSION Pressure Reducing Replace if over 3.5 bar
VALVE Valve faulty

When heater is heating Check charge of vessel. Re­Faulty Expansion charge vessel to 3.5 bar or
Vessel or lost charge replace if necessary

- 9 -

FAULT FINDING

3) Close taps in turn after having purged the system of air.

4) Check for leaks around the controls and Immersion Heaters and again after the unit has heated up.

5) Check that no water is passing to waste through the relief valves.

6) Test the operation of the Temperature & Pressure Relief and Expansion Valves by lifting/turning the manually operated
test lever/cap and observing that water flows through freely and safely to waste.

7) Check that the discharge pipe is plumbed so that it falls continuously and that no taps, valves or other shut off devices
are installed in the pipe.

8) Check that all thermostats are set at 60°C.

9) DIRECT UNITS. Switch on Immersion Heater(s) and allow unit to heat up. Check operation of Thermostat(s).

10) INDIRECT UNITS. Fill the indirect (primary) circuit following the boiler instructions. Switch on the boiler, ensure that the
programmer is to Domestic Hot Water. Allow unit to heat up and check operation of indirect thermostat on motorised
valve(s).

11) Demonstrate operation to user, including operation of Temperature & Pressure Relief Valve and what to do if it
operates.

12) Give this book to the user to retain for future reference and make the customer aware that periodic checks of the
equipment are essential for safety.

MAINTENANCE

No longer than every 12 months, the installer should check the Magnesium Anti-corrosion Anodes (consult the label on the
face of the unit for the correct location). Assessment of the condition of the bottom anode can be made by judging the
condition of the top anode.
If the heating element is heavily coated with scale we recommend descaling at the time of this inspection. The Expansion
Vessel may need to be recharged periodically by your installer.

WARNING :

SWITCH OFF THE POWER SUPPLY BEFORE WORKING ON THE APPLIANCE.

If the Thermal Cut-Out has operated the cause must be found before resetting.

Removal of top & bottom Anodes;

1) Close the mains supply service valve.

2) Open hot water taps.

3) Attach a hose and open the drain cock and allow the cylinder to empty.

4) The anodes are removed by unscrewed using an Allen key.

EXAMINE THE ANODES AND REPLACE IF THE DIAMETER IS LESS THAN 10mm.

The use of P.T.F.E. sealing tape is recommended to ensure watertight connection for Anodes.
Descale the Immersion Heater(s) and remove any lime deposit from the cylinder. Replace in reverse order. THIS DOES
NOT APPLY TO COMFORT MODELS.

Check controls as per the following:-

1) Check and clean the Line Strainer before refilling the system.

2) Check pressure in Expansion Vessel and top up as necessary.

3) Check manually by lifting the test lever, the Temperature & Pressure Relief Valve.

4) Check manually by turning the test knob the Expansion Relief Valve.

5) Check discharge pipes from both Temperature & Pressure Relief and Expansion Relief Valve for obstructions.

- 8 -

FIG. 1

MODELS CONTRACT

STD 100-125-150-210 DIRECT

- 11 -

C

B

315

F

A

45

22 30'

45

ST 50-80-100 CONTRACT

STD 100-125-150-210

45

22 30'

22 30'

45

C

B

D

275

315

F

A

CONTRACT & COMFORT

STI 125-150-210

230

90˚

F

C

120

625

230

360

315

120

STDI 300 - STT 300

795

45

F

700

C

120

230

355

500 ST6 - 500 STT6

TECHNICAL DATA

For the full specification of each unit pleae consult the labels atteched to the side of the unit.
Max Water supply Pressure 12.0 bar
Operating Pressure 3.5 bar
Expansion Vessel Charge Pressure 3.5 bar
Expansion Valve Setting 6.0 bar
Pressure And temperature relief valve 7.0 bar / 90° C
Immersion Heater Rating for Each Heater 3000 W - 240 V.
Pressure Reducing valve set pressure 3.5 bar

MODEL

STORAGE UNITS PIPES SIZE DIMENSIONS IN MM

WEIGHT

CAPACITY INLET OUTLET A B C D E F

WHEN

FULL KG

DIRECT RANGE

Wall Hung

CONTRACT ST 50
CONTRACT ST 80

CONTRACT ST 100

Floor Standing

CONTRACT STD 100
CONTRACT STD 125
CONTRACT STD 150
CONTRACT STD 210

STDI 300

500 ST6

INDIRECT RANGE

CONTRACT STI 125
CONTRACT STI 150
CONTRACT STI 210

STT 300

500 STT6
COMFORT STI 125
COMFORT STI 150
COMFORT STI 210

50 L
75 L

100 L

100 L
125 L
150 L
200 L
300 L
495 L

125 L
150 L
200 L
300 L
495 L
125 L
150 L
200 L

1/2”
3/4”
3/4”

3/4”
3/4”
3/4”
3/4”
3/4"

1”

3/4”
3/4”
3/4”
3/4”

1"
3/4”
3/4”
3/4”

410
590
550

530
700
840
990

-

-

700
840
990

-

­700
840
990

-

-

-

-

-

-

-

-

-

0.75

0.9

0.9

0.6

1.5

0.75

0.9

0.9

120
175
175

650
805
965

1280

-

-

805
965

1280

-

­805
965

1280

580
740
700

890
1045
1205
1525
1790
1870

1045
1205
1525
1790
1870
1045
1205
1525

160
230
230

-

-

-

-

-

-

675
815
815

-

­675
815
815

475
475
575

-

-

-

-

-

-

-

-

-

-

-

-

-

-

460
460
560

505
505
505
505
560
714

505
505
505
560
714
505
505
505

77
115
141

129
158
190
245
385
630

166
201
256
395
641
169
203
258

TABLE 1

- 10 -

COIL

SURFACE

m

2

MAX. 100MM

TABLE 1.1

Model

Time taken to raise temperature

from 15 C to 65C

Time taken to raise 70% of the

stored volume to 65 C

Contract STI 125*

15 mins

13 mins

Contract STI 210*

24 mins

21 mins

Comfort STI 125*

15 mins

12 mins

Comfort STI 210*

19 mins

16 mins

Contract STD 100

2 hrs 30 mins

1 hr 15 mins

Contract STD 210

1 hr 58 mins

1 hr 39 mins

* Indirectly heated. Figures obtained by WRc in accordance with Test Criteria 1-50-220 & 1-50-222.

FIG. 3

MODELS ST 50 - 80 - 100

COLD MAINS-IN

22 mm

(15 mm ST 50)

COMBINATION

VALVE

HOT

SUPPLY

22mm

(15 mm ST 50)

EXPANSION

VESSEL

PRESSURE + TEMPERATURE

RELIEF VALVE

TUNDISH

EXPANSION
RELIEF PIPE

28 mm

MAX. 100 mm

- 13 -- 12 -

FIG. 2

MODELS CONTRACT - COMFORT

STI 12

5 - 150 - 210 INDIRECT

MAX. 100MM

- 14 - - 15 -

FIG. 3

MODEL STDI 300 DIRECT

FIG. 3

MODEL STT 300 INDIRECT

A

B

MAX. 100 mm

MAX. 100 mm

- 16 - - 17 -

FIG. 3

MODEL 500 ST6 DIRECT

FIG. 3

MODEL 500 STT6 INDIRECT

C D

MAX. 100MM

MAX. 100MM

FIG. 5

COLD WATER COMBINATION VALVE 1/2”

15 mm
COLD
MAINS IN

15 mm

TO WATER

HEATER

3/4” B.S.P. CONNECTIONS
FOR EXPANSION VESSEL

EXPANSION RELIEF

VALVE (SET AT 6 BAR)

NON-RETURN

VALVE (WITHIN HOUSING)

TEE PIECE

FOR BALANCED

COLD WATER

TAKE OFF

(NOT SUPPLIED)

SERVICEABLE 1/2 PRESSURE

REDUCING CARTRIDCE AND LINE

STRAINER

- 19 -

FIG. 4

COLD WATER COMBINATION VALVE 3/4”

22 mm COLD
MAINS IN

22 mm COLD
MAINS IN

22 mm TO WATER HEATER

3/4” B.S.P. CONNECTION
FOR EXPANSION VESSEL

22 mm TO WATER HEATER

NON-RETURN VALVE

(WITHIN HOUSING)

22 mm BALANCED COLD WATER TAKE OFF

WITH NON-RETURN VALVE

15 mm EXPANSION RELIEF
OUTLET TO TUNDISH

SERVICEABLE 3/4 PRESSURE REDUCING
CARTRIDGE AND LINE STRAINER
(SET AT 3.5 BAR)

EXPANSION RELIEF VALVE
(SET AT 6 BAR)

3.5

6 BAR

- 18 -

FIG. 7

SUGGESTED WAYS OF TERMINATING

DISCHARGING PIPES SAFETY

- 21 -

FIG. 6

300L AND 500LONLY

RETURN

FLOW

DRAIN

NON-RETURN

FROM BRONZE

PUMP

SECONDARY

RETURN

- 20 -

500 mm Max.

300 mm
Min.

Temperature & pressure
relief valve

Metal discharge pipe (D1) from
temperature & pressure relief valve.
to tundish.

Metal discharge pipe (D2) from tundish
with continuous fall. See Table 2 and worked
example.

Tundish

Fixed grating

Trapped gulley

Discharge below
fixed grating.
(see page 6 for
alternative points
of discharge).

Valve outlet size Minimum size of

discharge pipe D1*

Minimum size of

discharge pipe D2*

from tundish

Maximum

resistance allowed,

expressed as a

length of pipe (i.e.

no elbow or bends)

Resistance created

by each elbow or

bend

G ½ 15 mm 22 mm

28 mm
35 mm

Up to 9 m
Up to 18 m
Up to 27 m

0.8 m

1.0 m

1.4 m

G ¾ 22 mm 28 mm

35 mm
42 mm

Up to 9 m
Up to 18 m
Up to 27 m

1.0 m

1.4 m

1.7 m

G 1 28 mm 35 mm

42 mm
54 mm

Up to 9 m
Up to 18 m
Up to 27 m

1.4 m

1.7 m

2.3 m

Table 2. Sizing of copper discharge pipe “D2” for common temperature valve outlet sizes.

WORKED EXAMPLE

The example below is for a G ½ Temperature & Pressure Relief valve with a discharge pipe
(D2) having 4 no. elbows and length of 7m from the Tundish to the point of discharge.

From Table 2
Maximum resistance allowed for a straight length of 22mm copper discharge pipe (D2) from G
½ T & P valve is 9m.
Subtract the resistance for 4 no. 22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to: 5.8m.
As 5.8m is less than the actual length of 7m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 28mm pipe (D2) from G ½ T & P valve
equates to: 18m.
Subtract the resistance for 4 no. 28mm elbow at 1.0m each = 4m.
Therefore the maximum permitted length equates to: 14m
As the actual length is 7m, a 28mm (D2) copper pipe will be satisfactory.

FIG. 9

a) SINGLE ELEMENT

RECOMMENDED ECONOMY 7 SYSTEMS

THERMAL
CUT-OUT

PIPES

THERMOSTAT POCKET

L1

N

THERMOSTAT

DAY
ELEMENT
3 KW
240 V

THE IMMERSION HEATER SHALL BE INSTALLED WITH 85°C
RUBBER INSULATED HOFR-SHEATHED FLEXIBLE CORDS
COMPLYING WITH TABLE 8 OF BS 6141 : 1981

THE FOLLOWING DRAWING MUST BE REFERRED TO BEFORE
THE SIDE MOUNTED IMMERSION HEATER IS REPLACED.

WALL

DIAG. 4

- 23 -

FIG. 8

RECOMMENDED ECONOMY 7 SYSTEMS

SYSTEM A

SYSTEM B

- 22 -

FIG. 11

SCHEME OF ELECTRICAL CONNECTIONS WITH 2 MOTORISED VALVES 2 WAY

T6360B

ROOM

THERMOSTAT

14
35
22

OR

CM 41
CM 51

A

B

1

5

V4043H

HEATING VALVE

BROWN

5

BLUE

2

GREY

1

ORANGE

10

GREEN/YELLOW

3

V4043H

HOT WATER VALVE

BROWN

8

BLUE

2

GREY

1

ORANGE

10

GREEN/YELLOW

3

Honeywell ST 699B 1002

63 N L

Link L-5-8

ST 6400/ST 6300 ST 6200 3 4 N L

Drayton Tempus 7 3 4 N L

Horstmann 425, 525, 527

14 ENL

Link L-2-5

Landis & Gyr RWB2

34 N L

Glowworm Mastermind

Landis & Gyr RWB20

34 N L

Microgyr

Potterton Miniminder 3 4 N L

Potterton EP2000/3000 - 3 4 N L

Link L-5 EP2001/3001

Randall 102/102 E 1 2 E 5 6

Link 3-6

Randall 4033

42 E76

Link 1-6

Randall 701, 702

31 ENL

Link L-6-5

Sangamo M5 1 8 E 4 3

Link 1-6

Sangamo 410 Form 1

18 E4 3

Link 3-6

PROGRAMMER

64321

Pegler Sunvic

25 ENL

SP 50/100 (Link L-3)

Switchmaster

14 N L

Symphony, Sonata

Switchmaster 400, 600 3 1 N L

SWITCHMASTER 805, 900

31 N L

Sunvic ET 1451

74 E1 2

Link 2-3-6

Sunvic DHP 2201 6 3 E 1 2

Towerchron FP

610 2 1

Link 1-5/4-7-9

Towerchron MP

610 2 1

Link 1-4/6-11

Towerchron 2000 HW HTG

NL

ON ON

ACL LS522, LS722 3 4 N L

Randall 922, 972

36 ENL

Link L-2-5

Randall 3020 P

42 ENL

and 3060

PROGRAMMER

64321

Basic Boilers (see Page 27) L E N L N E

Barlo Balmoral 45F, 55F, 65F 9 6 10 11 12 L N E

Barlo Blenheim 30BF To 75BF LP 2 E N L L N E

Baxi Solo 30PF To 70PF PL SL E N L L N E

Glowworm Economy 24

7 SL E N L L N E

(remove link SL-9)

Glowworm Economy 30B To 50B

9 12 E 10 11 L N E

range (remove link 12-7)

Glowworm Fuelsaver MKII & F

9 12 E 10 11 L N E

range (remove link 12-7)

Glowworm Fuelsaver BR & R

7 SL E N L L N E

range (remove link SL-9)

Glowworm Spacesaver KFB50

9 12 E N L L N E

(remove link 12-7)

Glowworm Spacesaver 75

581 325 46

(remove link 7-8)

Ideal Excell

Ideal Turbo 2 LP LB E N L L N E

Ideal Mexico Super 2

Myson Apollo

(remove all links)

PL ON E N L L N E

Myson Olympic (Use RED Plug)

(remove all links)

Myson Orion (After SEPT 88)

PL 4 E N L L N E

(remove all links)

Myson Economist Ro Ri E N L L N E

Potterton Flamingo (After June 89) PL SL E N L L N E

Potterton Netaheat 16-22 (Link 7-8) 6 7 E N L L N E

Potterton Netaheat Profile PL SL E N L L N E

For Vaillant VC/VCW and

Vokera 12-48 RSE contact office

for special wiring diagram

BOILER PUMP

9 10 3 2 1 9 10 2 3

1

P

Cylinder

thermostat

Thermal

cut-out

ELEMENT

3 KW 240V

~

Thermal

cut-out

Thermostat

1

8

6

Not
used

L1

240V~

N

P

2

1 P

2

240V

MAINS INPUT (3 AMP)

L1
N2
E3

240V

MAINS INPUT (13 AMP)

E
L
N

• 1

• 2

• 3

• 4

• 5

• 6

• 7

• 8

• 9

• 10

TYPICAL

JUNCTION BOX

- 25 -

FIG. 10

For 300 L modles only

a) SINGLE ELEMENT

RECOMMENDED ECONOMY 7 SYSTEMS

THERMAL
CUT-OUT

L2

N

L1

N

THERMOSTAT

DAY ELEMENT
3 KW 240 V

~

NIGHT ELEMENT
3 KW 240 V

~

ECONOMY 7

THE IMMERSION HEATER SHALL BE INSTALLED WITH 85°C
RUBBER INSULATED HOFR-SHEATHED FLEXIBLE CORDS
COMPLYING WITH TABLE 8 OF BS 6141 : 1981

THE FOLLOWING DRAWING MUST BE REFERRED TO BEFORE
THE SIDE MOUNTED IMMERSION HEATER IS REPLACED.

DIAG. 4A

THERMOSTAT MOUNTED

ON THE TOP

THERMAL

CUT-OUT

THERMOSTAT

- 24 -

Basic Boiler List

Baxi Bermuda range

Boston RS and OF range

Glowworm Complheat

Hideaway range 65 - 80
Ultimate 40 - 80

30B - 80B, 30CF - 60CF

Halstead Buckingham range

Potterton Kingfisher range

Statesman range (oil fired)

Caradon Ideal Classic range

Mexico Ssper range
Mexico Slimline range

Newflame Boilers Backboiler range

Condensing Boiler List

CARADON IDEAL Minimiser FF30 - FF80 L E N
GLOWWORM Energysaver (Remove link SL-9) PL SL E N L
KESTON L E N
POTTERTON Envoy 30F - 80F PL SL E N L

refer to

VAILLANT VU 186, 226 manufacturers

instructions

Boiler Connections

2 Motorised values 2 way (see fig. 11) 9 10 3 2 1
1 Motorised value 3 way (see fig. 12) 9 8 3 2 1

Pump Connections

2 Motorised values 2 way (see fig. 11) 9 3 2
1 Motorised value 3 way (see fig. 12) 9 3 2

- 27 -

FIG. 12

SCHEME OF ELECTRICAL CONNECTIONS WITH MOTORISED VALVE 3 WAY

V4043A

MID. POS. VALVE

WHITE

5

BLUE

2

GREY

7

ORANGE

8

GREEN/YELLOW

3

Honeywell ST 699B 1002

76 3 NL

Link L-5-8

ST 6400/ST 6300 1 3 4 N L

ST 6200 3 4 N L

Drayton Tempus 7 1 3 4 N L

Horstmann 425, 525, 527

31 4E NL

Link L-2-5

Landis & Gyr RWB2

13 4 NL

Glowworm Mastermind

Landis & Gyr RWB20

13 4 NL

Microgyr

Potterton Miniminder 1 3 4 N L

Potterton EP2000/3000 - 1 3 4 N L

Link L-5 EP2001/3001

Randall 102/102 E 1 2 E 5 6

Link 3-6

Randall 4033

54 2E 76

Link 1-6

Randall 701, 702

43 1E NL

Link L-6-5

Sangamo M5 1 8 E 4 3

Link 1-6

Sangamo 410 Form 1

21 8E 43

Link 3-6

PROGRAMMER

764321

Pegler Sunvic

12 5E NL

SP 50/100 (Link L-3)

Switchmaster

31 4 NL

Symphony, Sonata

Switchmaster 400, 600 3 1 N L

SWITCHMASTER 805, 900

43 1 NL

Sunvic ET 1451

87 4E 12

Link 2-3-6

Sunvic DHP 2201 8 6 3 E 1 2

Towerchron FP

86 10 21

Link 1-5/4-7-9

Towerchron MP

610 21

Link 1-4/6-11

Towerchron 2000 HW HW HTG

NL

OFF ON ON

ACL LS522, LS722 1 3 4 N L

Randall 922, 972

13 6E NL

Link L-2-5

Randall 3020 P

42ENL

and 3060

PROGRAMMER

764321

Basic Boilers (see Page 27) L E N L N E

Barlo Balmoral 45F, 55F, 65F 9 6 10 11 12 L N E

Barlo Blenheim 30BF To 75BF LP 2 E N L L N E

Baxi Solo 30PF To 70PF PL SL E N L L N E

Glowworm Economy 24

7 SL E N L L N E

(remove link SL-9)

Glowworm Economy 30B To 50B 9 12 E 10 11 L N E

range (remove link 12-7)

Glowworm Fuelsaver MKII & F 9 12 E 10 11 L N E

range (remove link 12-7)

Glowworm Fuelsaver BR & R 7 SL E N L L N E

range (remove link SL-9)

Glowworm Spacesaver KFB50 9 12 E N L L N E

(remove link 12-7)

Glowworm Spacesaver 75

581 325 46

(remove link 7-8)

Ideal Excell

Ideal Turbo 2 LP LB E N L L N E

Ideal Mexico Super 2

Myson Apollo

(remove all links)

PL ON E N L L N E

Myson Olympic (Use RED Plug)

(remove all links)

Myson Orion (After SEPT 88)

PL 4 E N L L N E

(remove all links)

Myson Economist Ro Ri E N L L N E

Potterton Flamingo (After June 89) PL SL E N L L N E

Potterton Netaheat 16-22 (Link 7-8) 6 7 E N L L N E

Potterton Netaheat Profile PL SL E N L L N E

For Vaillant VC/VCW and

Vokera 12-48 RSE contact office

for special wiring diagram

BOILER PUMP

9 8 3 2 1 9 8 2 3

240V

MAINS INPUT (3 AMP)

L1
N2
E3

240V

MAINS INPUT (13 AMP)

E
L
N

- 26 -

T6360B

ROOM

THERMOSTAT

14
35
22

OR

CM 41
CM 51

A

B

1

5

ELEMENT

3 KW 240V

~

Thermal

cut-out

Thermostat

L1

240V~

N

• 1

• 2

• 3

• 4

• 5

• 6

• 7

• 8

• 9

• 10

TYPICAL

JUNCTION BOX

1

P

Cylinder

thermostat

Thermal

cut-out

1

8

6

Not
used

P

2

1 P

2

928 238/02

Guarantee

We, MTS, guarantee that should this water heater prove to be defective by
reason of faulty workmanship or material during the periods stated below, we will
replace the defective parts (or product) free of charge on the condition that :

• The appliance has been correctly installed by a competent installer and used
only on the supply voltage stamped on the rating plate.

• The appliance has been used and maintained in accordance with these
instructions and has not been tampered with or otherwise subjected to misuse
neglect or accident.

• The appliance has not been taken apart, modified or repaired except by a MTS
authorised Service Engineer*.

• Evidence of the date of purchase in the form of an invoice receipt (or hire
purchase documents) is not included with the appliance returned under
guarantee.

The guarantee will be applicable from the date of purchase or commencement of
hire purchase for the following periods :

On Contract models:

• 12 months on electrical parts and components

• 3 years on the cylinder tank
On all other models:

• 12 months on electrical parts and components

• 5 years on the cylinder tank
* Important : the guarantee period on the tank will apply only if the annual

inspection will have been carried out by a MTS authorised Service Engineer.
* A MTS authorised Service Engineer is :

1. the installer of the appliance.

2. a MTS approved Service Centre

3. an engineer who has attended a MTS training course in unvented storage
water heaters.

Manufactured by
MTS Benelux sa/nv

Zone industrielle
5020 MALONNE (BELGIQUE)
Tél. : [phone]
Fax : [phone]
Télex : 59345 Thorfa B

Commercial subsidiary
MTS (GB) LIMITED

MTS Building
Hughenden Avenue
High Wycombe
Bucks HP 13 5 FT
Telephone: [phone]
Fax: [phone]

Technical Service Hotline : [phone]