GEMTEX Heating Solutions Ltd GTX 500 User manual

HEATING SOLUTIONS LTD
GTX manual
[e-mail] www.gemtex.co.uk01256 587 800

HEATING SOLUTIONS LTD

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1
Contents
Item no Item Page
1. Presentation 2
2. Range 2
3. Technical Specifications 2
4. Dimensions 3
5. Connection details and components 4
6. Installation Guide 4
7. Unvented kit 22mm for 150 litre 9
8. Unvented kit 28mm for 200/300 litre 10
9. Unvented kit 1¼” for 500 litre 11
10. Tundish requirements 12
11. Electrical Diagram GTX 150, 200 and 300 13
12. Electrical Diagram GTX 500 13
13. Hot water temperature control via boiler with electronic regulation 14
14. Hot water temperature control with mechanical thermostat 14
15. Commissioning 15
16. Maintenance 15
17. Parts List 16
18. Warranty Terms 16

2GEMTEX HEATING SOLUTIONS LTD
The GTX range of tanks are high performance hot water
production systems used to provide fast recovery hot water,
the concept is to store less hot water than traditional tanks
and recover the tank rapidly using the high output coiled
heat exchanger to absorb the boiler power and allowing
condensing boilers to operate at peak efficiency during hot
water production.
The tanks are made of 316L stainless steel with an insulation
of injection moulded polyurethane rigid foam encapsulated in
a tough white PVC outer casing.
Each tank is fitted with a control panel with an on/off switch,
a changeover switch from boiler to immersion heater, an
overheat thermostat and a control thermostat for the
immersion. The control panel is pre-wired with a mains cable
for the L, N and E and the cable to power the energy shut
off valve which exits the insulation near the primary flow
connection.
The top of the tank is pre-fitted with a 7 bar P&T valve and
has a spare connection that can be fitted with an anti-vacuum
valve or our cathodic protection system if the installation
requires. The very base of the tank has a connection allowing
for the installer to fit our full-bore drain valve for fast flushing
and draining of the entire tank volume of water.
Model Capacity Litres
GTX 150 150
GTX 200 200
GTX 300 300
GTX 500 500
GEMTEX
Capacity Exchange Coil Power Primary Loss Continuous Heat Energy Heater
(L) Surface Volume (Kw) Flow of Load Production Loss Efficiency (Kw, V)
(m²) (L) ((L/h) (mWC) ((L/h) (w)
150 L 0,98 4,33 34 1.460 0,70 835 52 B 3, 230
200 L 1,80 8,02 57 2.400 3,25 1,376 57 B 3, 230
300 L 1,97 8,72 61 2.600 4,00 1,500 88 C 3, 230
500 L 4,47 19,92 100 4.300 7,25 2,460 96 C 6, 400
Temperature of primary circuit: 80°C/60°C
Temperature of secondary circuit 10°C/45°C
Maximum Domestic hot water storage temperature 80°C
Overheat thermostat 90°C
P&T valve 7Bar 90°C
Max service pressure 8Bar
1. Presentation
2. Range
3. Technical Specifications

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4. Dimensions

4GEMTEX HEATING SOLUTIONS LTD
5. Connection Details and Components
The appliance must be installed and maintained by a
qualified certified professional who is approved to install
unvented hot water tanks, according to current statutory
and industry standards in accordance with G3 Building
Regulations.
The tank itself comes ready for electrical and mechanical
connections to the installation. However, the unvented kit
which is supplied in a separate package must be assembled
and connected by the installer.
When required by Building control or local bylaws, a thermostatic
mixer must be placed on the domestic hot water supply system
to limit the temperature at the drawing point (50°C).
Check that the primary circuit pressure (exchanger) does not
exceed 8 bars or the maximum acceptable boiler pressure if
this is less than 8 bars.
When the domestic hot water production system has been
selected to provide its maximum performance, check that
the boiler’s flow rate, primary temperature and power are
respected according to those of the tank exchanger.
NOTE TO INSTALLER:
Please read this manual fully prior to commencing installation.
Leave the manual with the householder after installation of
the Gemtex hot water tank.
6. Installation Instructions

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Models GTX 150 GTX 200 GTX 300 GTX 500
Operating Pressure 3.5 bar 3.5 bar 3.5 bar 3.5 bar
Max Water Supply Pressure to unvented kit 12 Bar
Expansion relief Setting 6 Bar
Nominal Capacity 150 200 300 500
Pressure and Temperature relief valve 7 Bar/90°C
Expansion vessel charge pressure 3.5 Bar
Empty weight 33 44 61 84
Connections
Cold water inlet 3/4” 3/4” 1” 1”
Hot water outlet 3/4” 3/4” 1” 1”
Secondary return 3/4” 3/4” 3/4” 3/4”
Primary flow from boiler 3/4” 3/4” 1” 1”
Primary return to boiler 3/4” 3/4” 1” 1”
Drain 3/4” 3/4” 3/4” 3/4”
Anti-Vac 3/4” 3/4” 3/4” 3/4”
6. Installation Instructions
To avoid damage the unit should be carried into position
within its packaging and on its pallet. Once in position or near
the final position, the pallet should be removed.
The tank should be installed on a floor designed to take the
weight of the tank when full of water. Each litre of water
weighs 1 Kg. The actual water content of each tank should
be added to the tank weight to obtain the total weight
of the tank when full to ascertain if the floor is of suitable
construction.
The incoming cold-water supply pipe must be fitted with a
stopcock or isolation valve before the cold water unvented kit.
A full bore drain cock/valve must be fitted to the drain
connection of the tank.
Water hardness. The water hardness should not exceed the
acceptable level, which is 100 mg/l, and 150 mg/l of chlorides
(Cl-) If it does then a water softening device should be fitted
and our permanent cathodic protection system.
Kit installation
The positioning of the tundish shall be visible to the
occupants and shall be positioned away from any electrical
devices.
See page 11 drawing number GT-ST-02 for the details of the
tundish and discharge position pipe connection details. The
relief valve connection should not be altered or used for any
other type of connection.
Before connecting the primary pipework, fit the Honeywell
safety shut off zone valve to the primary flow inlet of the tank.
150 mm clearance should be left on the top of the tank for
access to the connections and P&T valve.
No valve shall be fitted between the tank and the expansion
vessel.
No other immersion, other than the GTX immersion supplied
by Gemtex should be fitted to the tank.
The GTX range of cylinders is ideally suited for connection
to our Gemtex boilers to match the coil ratings. However,
connection to non – Gemtex boilers can be carried out if
required, if you are not using a hot water sensor you can fit
our mechanical thermostat part no S55700-P111 and see
Section 14 on page 13 for details.
To flush through the tank after installation, simply open the
drain, and flush through the tank to the drain by using the
cold feed supply. If the tank has been left for any length of
time filled with water, then normal chlorination procedures
should be followed in accordance with current regulations.
This tank should only be used with gas or oil boilers or with
bio-mass boilers with thermostatic control. It should not be
used with solid fuel appliances without regulation.
Please note that if a secondary hot water circuit is used then
an additional expansion vessel may be required to consider
the additional water volume of this circuit.
In hard water areas you should not exceed 60°C as a store
temperature.

6GEMTEX HEATING SOLUTIONS LTD
Important Notice
The safety shut off zone valve is an important safety
device of the unvented GTX tank and must be installed.
Fit the valve to the flow pipework from the boiler
adjacent to the tank. The valve is to be controlled via
the small core L, N and E wire leaving the control panel
of the tank. Drawing number GS-ST-02 page 5 showing
how to connect the “Safety shut off zone valve” to the
tank installation.
Safety Discharge Pipe from Tundish
See Table below for sizing details of safety discharge pipe
from our tundish.
Worked example:
The example below is for a G 1/2 temperature 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
Maximum resistance allowed for a straight length of 22mm
copper discharge pipe (D2) from a G 1/2 temperature relief
valve is 9.0m.
Subtract the resistance for 4 no. 22mm elbows at 0.8m each
= 3.2m
Therefore, the maximum permitted length equates to: 5.8m
5.8m is less that the actual length of 7m, therefore calculate
the next largest size.
Maximum resistance allowed for a straight length of 28mm
pipe (D2) from a G1/2 temperature relief valve equates to
18m.
Subtract the resistance for 4 no. 28mm elbows 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
As an unvented tank it is necessary to fit the “unvented
kit” on the cold-water supply. The “Unvented kit”
contains a pressure reducing valve, non-return valve,
pressure relief valve and optional use balanced cold
water connector. Please see section 7 for details of the
22mm kit for the 150 litre. Section 8 for details of the
28mm kit for the 200 and 300 litre tanks and the section
9 for details of the 1 1/4” kit for the 500 litre tanks.
6. Installation Instructions
Table
Sizing of copper discharge pipe D2 for common temperature relief valve outlet sizes
Valve Outlet Minimum Size Minimum Size Maximum resistant Resistance
Size of Discharge of Discharge allowed expressed as a created by
Pipe D1 Pipe D2 from length of straight pipe each bend
tundish (i.e. no elbows or bends)
G 1/2” 15mm 22mm Up to 9m 0.8m
28mm Up to 18m 1.0m
35mm Up to 27m 1.4m
G 3/4” 22mm 28mm Up to 9m 1.0m
35mm Up to 18m 1.4m
42mm Up to 27m 1.7m

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Function
Pressure reducing valves (PRV) are installed in domestic water
systems to reduce and stabilise the inlet pressure from the
mains supply, which is generally too high and variable for
domestic appliances to function properly.
Description
The unit comprises of two parts, a pressure reducing valve and
a manifold containing a check valve, a cold water balancing
port and a preset pressure relief valve.
They can be fitted together or as separate units, either
horizontally with the spring chamber of the PRV upper most
or vertically with the PRV always first in line.
Installation
Carefully follow these instructions and ensure that the
installation conforms to the Water Regulations.
Ensure that sufficient water pressure and flow rate are
available.
Open fully all taps before installing the unit to flush the system
and expel any air remaining in the pipes.
It is recommended that isolating valves are installed upstream
and downstream to facilitate any future maintenance.
Install the PRV and manifold with the embossed arrow
pointing in the direction of flow.
The black plugs are a connection for a pressure gauge,
which is available when specified.
Rotate the pressure relief valve to the required position.
Ensure that the pressure relief valve discharge pipework
has a continuous fall and terminates in such a position
as not to cause injury.
The manifold contains a check valve and may be used as a
balanced cold water supply. If not used fit a blanking piece.
(Not supplied)
The connection on the manifold is used when an expansion
vessel is required or may be used for a drain off. If not used
fit a blanking piece. (Not supplied)
1 Pressure Reducing Valve
2Manifold Assembly
322mm Balanced Take Off
4Connection for Vessel
5Gauge – PT Point
6Safety Relief Valve
6. Installation Instructions
1
2
3
5
6
4

8GEMTEX HEATING SOLUTIONS LTD

Cap 
Calibration 
Screw 
Calibration
Close the downstream isolating valve.
Unscrew the cap and using an Allen key adjust the outlet
pressure by turning the calibration screw in the centre of the
cover.
Rotate it clockwise to increase the outlet pressure and
anticlockwise to reduce it.
Maintenance and Servicing
Under normal circumstances the unit should not require
any maintenance, but regular inspection and cleaning is
recommended.
Isolate the water supply to the pressure reducing valve.
Remove the cap and using an Allen key rotate the central
calibration screw anticlockwise to decompress the spring.
Note: Caution should be exercised when disassembling the
unit.
Remove the cover using a spanner on the hexagon faces.
Extract the cartridge with the aid of long nosed pliers to grip
the head of the set screw.
Remove the strainer element.
Clean the strainer element and cartridge under clean running
water.
If the strainer or cartridge are damaged replace.
Refit the strainer, cartridge and cover.
Turn on the water supply and check for leakage.
Re-calibrate the pressure reducing valve.
6. Installation Instructions
1 Cap
2Calibration Screw
3Spring
4Cartridge
5Strainer
1
2
3
4
5

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7. Unvented kit 22mm
1Unvented kit
2Safety zone valve
3Expansion vessel
4Expansion vessel connection
5Tundish
6Vessel connection hose
7Bracket and fixings
8Blank plug for unused connection
9Kit fully assembled
1
2
65
3
8
4
7
9

10 GEMTEX HEATING SOLUTIONS LTD
8. Unvented kit 28mm
1Unvented kit
2Safety zone valve
3a Expansion vessel – 200 litre tank
3b Expansion vessel – 300 litre tank
4Bracket and fixings (3a only)
5Tundish
6Vessel connection hose
7Blank plug for unused connection
8Kit fully assembled
1
2
6
5
3a
3b
7
4
8

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9. Unvented kit 1 ¼”
1a Non return valve for unvented kit
1b Pressure reducing valve for unvented kit
1c Pressure gauge for unvented kit
1d Pressure relief valve for unvented kit
1e Vessel connection hose
1f Expansion vessel
2Safety zone valve
3Tundish
4Connecting nipples
5Blank plug for unused connection
In order of assembly:
1a 1c
1e 1f
1d
1b
2
5
3
4

12 GEMTEX HEATING SOLUTIONS LTD
Please see drawing number GT-ST-02 from section 5 and the
alternative drawing below when there is no other option but
to use a HepvO trap.
10. Tundish requirements
1
2
3
4
5
6
7 8
9
EBS-17-3E
300 mm minimum
from tundish to bend (Building Regulations requirements)
300mmbetweenpipeclips
200 mm minimum
height above HepvO Valve
Note: This detail is only to be used where there is no other alternative. It is strictly subject to local.
Dispensation and approval must be sought from NHBC and Building Control inspector prior to installation.
This drawing has to be read in conjunction
with the full installation manuals supplied
122 mm copper discharge
pipe
2Tundish – visible point
off discharge
328 mm copper discharge
pipe
432 mm HepvO valve
5HepvO valve must be
vertical and adjacent
to the water unit, to be
visible & easily accessible
632 mm poplypropylene
waste pipe
7Pipe clip to be positioned
close to valve to provide
additional support
8Waste typically
discharged to soil stack
through boss adapter
9Soil stack

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The control panel is pre-wired for the mains power supply for
the immersion which is the large core cable and a smaller core
cable for the safety shut off zone valve.
11. Electrical diagram for the GTX 150, 200 and 300
The control panel is pre-wired for the mains power supply for
the immersion which is the large core cable and a smaller core
cable for the safety shut off zone valve.
12. Electrical diagram for the GTX 500

14 GEMTEX HEATING SOLUTIONS LTD
The sensor pocket item 5 on drawing number GT-ST-01
shown in section 4 on page 4. The sensor pocket is used in
conjunction with heat sink compound to get a good heat
transfer to the sensor. The screw clamp is used to retain the
sensor. Do not overtighten to prevent damage to the sensor.
13. Hot water temperature control via boiler with electronic regulation
When used with a system that does not have electronic
control please use the optional control thermostat specifically
designed for mounting on a pocket, Gemtex part no
S55700-P111 Please see photo below. This thermostat can
then be used to control non Gemtex control systems like a Y
plan or S plan system or similar.
14. Hot water temperature control with mechanical thermostat

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15. Commissioning
•Check all pipe connections for tightness. Close drain cock.
•Check pressure(s) in expansion vessel(s) 3.5 bar. Recharge
if necessary.
•Fill primary circuits, vent and check for leaks.
•Chock open P&T valve on top of tank (by fitting manual
lever).
•Open stopcock and fill tank with water until if freely
discharges through the outlet from the P&T valve.
•Remove chock and close P&T valve.
•Test delivery of water from tank by opening and running
all taps, both hot and cold water and any other water
discharges points (showers etc).
•Check operation of expansion relief valve on Cold Water
Supply kit by twisting the manual release lever and
discharging water.
•Check all pipework and connections for leaks.
Heating of the tank by the boiler
Move the switch on the tank control panel to boiler. Check
that the safety shut off zone valve is opened when power is
applied to the control panel and closes when the power is
turned off.
Heating of tank from electric immersion heater
Move the switch on the tank control panel from boiler to
immersion, the thermostat control knob is used to set the
temperature and the actual temperature is shown on the
thermometer.
User Information
The installer must train the user on how the appliance works
and how to isolate it. In particular, the user must be informed
of the role and operation of the safety mechanisms and
the need to have the appliance maintained regularly by a
qualified professional.
WARNING TO THE USER
Do not remove or adjust any component part of the unvented
hot water tank: contact the installer.
If this unvented water heater develops a fault, such as flow of
hot water from the discharge pipe, switch the heater off and
contact the installer.
16. Maintenance
BEFORE COMMENCING ANY MAINTENANCE WORK,
ISOLATE ALL MAINS ELECTRICITY SUPPLIES TO
THE SYSTEM
The tank and unvented Kit should be inspected annually.
•Close the cold-water inlet supply isolation valve.
•Open the hot water outlets.
•Drain down hot water system including the tank Use drain
cock.
•Check pressure in expansion vessel(s) and recharge to
3.5 Bar, if necessary.
•Remove filter in line strainer. Clean or replace.
•Reassemble. Refill system.
•Check all pipework for leaks.
•Open P&T valve and check that it discharges water and
then shuts off.
•Open expansion relief valve and check that it discharges
water and then shuts off.
•Check operation of all controls.

16 GEMTEX HEATING SOLUTIONS LTD
17. Parts List
1. 00094 – Safety Thermostat.
2. 00070 – 230v Control Thermostat.
3. 01246 – 415v Control Thermostat.
4. 01119 – Thermometer.
5. 04114 – 230v Control panel assembly complete with
wiring and thermostats and control switches.
6. 07007 – 415v Control panel assembly complete with
wiring and thermostats and control switches.
7. 03802 – 3kW immersion heater element
8. 06357 – 6kW immersion heater element
9. 309570 – P&T valve
10. V4043H1056/U – 22mm Energy shut off valve
11. V4043H1106/U – 28mm Energy shut off valve
12. PV18W – litre expansion vessel for GTX 150
13. PV25W – litre expansion vessel for GTX 200
14. PV33W – litre expansion vessel for GTX 300
15. PV50W – litre expansion vessel for GTX 500
16. G-133-3008 – 150 litre unvented kit
17. G-133-3009 – 200 litre unvented kit
18. G-133-3010 – 300 litre unvented kit
19. G-133-3011 – 500 litre unvented kit
20. A3115051 – 6 Bar Pressure relief valve for 100 litre tank
21. F0000668 – 6 Bar Pressure relief valve for 200 & 300 litre
tank
22. 311560 – 6 Bar Pressure relief valve for 500 litre tank
23. AP-400011 – Tundish 22mm x 28mm
24. S55700-P111 – Optional Siemens mechanical
thermostat
25. 02710 – Permanent cathodic corrosion protection system
18. Warranty Terms
a) The installation of the GTX Tank should be carried out
strictly in accordance with this instruction manual and all
local Water and Building Regulations, failure to do so will
invalidate any warranty.
b) In accordance with good installation practise, the water
hardness should be controlled by either a water softener
or water descaling device to ensure the water hardness.
The acceptable level of water hardness is 100 mg/l, and
150 mg/l of chlorides (Cl-). For higher levels of chlorides,
between 150 and 250 mg/l, you must install our anode
protection. If you install a water softener you must
ensure the PH level does not go lower than 6.5. Any
claims for scale related water damage will be rejected.
c) The tank has a warranty of 10-years and the electrical
components are warrantied for 2-years.
d) For the full details of our terms and conditions please
see our website https://www.gemtex.co.uk/terms-and-
conditions/
Every two years, the following additional maintenance
should also be carried out after draining down.
•Remove Electric Immersion Heater cover.
•Disconnect wiring to Immersion Heater.
•Undo immersion heater with a box spanner or the correct
size immersion heater spanner.
•Inspect heater elements and de-scale if necessary.
•Inspect interior of tank.
•Re-assemble using a new gasket on the flange.
•Re-connect Immersion Heater wiring.
•Refill system and check for leaks around flange.
•Replace Electric Immersion Heater cover.
•Check operation.

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18 GEMTEX HEATING SOLUTIONS LTD
HEATING SOLUTIONS LTD
01256 587 800
Gemtex Heating Solution Ltd
65 Basepoint Business Centre
Aviation Business Park
Enterprise Close
Christchurch
BH23 6NX
inf[email protected]
www.gemtex.co.uk
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Gemtex reserves the right to make changes and improvements
which may necessitate alteration to the specification without
prior notice. This is not a contractual document.
FORM1018a