gledhill StainlessLite HP180IND User guide

Design, Installation & Servicing Instructions
Models covered in this manual
Stainless Lite HP Direct 180-400 litres
StainlessLite HP
Unvented cylinders specifically designed to work with a heat pump

Page 2
Section Page
DESIGN
Description 3
Technical Information 5
System Design 6
INSTALLATION
Installation 7
Commissioning 18
USER INSTRUCTIONS 19
SERVICING AND MAINTENANCE
Servicing and Maintenance 20
Fault Finding 21
Short Parts List 23
APPENDIX
Appendix A 24
Appendix B 25
Benchmark Checklist 26
Benchmark Service Record 27
Notes 28
Terms & Conditions 30
ISSUE 3:05-11
These instructions should be read in conjunction with the installation/servicing
instructions issued by the manufacturer of the heat source being used.
Any installation must be in accordance with the relevant requirements of the Gas
SafetyRegulations,BuildingRegulations,I.E.E.WiringRegulationsandtheWaterFitting
Regulations (England and Wales) or Water Byelaws (Scotland). It should be read in
accordance with the relevant recommendations of the following:
BS 6798;BS 5549;BS 5546;
BS 5440:1;BS 5440:2;CP 331:3
BS 6700:BS 5258 and BS 7593:1992
Stainless Lite is covered by Section G3 of the Building Regulations (England and
Wales)TechnicalStandardP3(Scotland)andBuildingRegulationP5(NorthernIreland).
Compliance can be achieved via a Competent Person Self Certification Scheme or
notificaton of installation to the Local Authority Building Control Department.
It must be installed by a competent person as defined by the relevant regulations.
Manufacturers notes must NOT be taken as over-riding statutory obligations.
This appliance is not intended for use by persons (including children) with reduced
physical,sensory or mental capabilities,or lack of experience and knowledge unless
they have been given supervision or instruction concerning use of the appliance by
a person responsible for their safety. Children should be supervised at all times to
ensure they do not play with the appliance.
This information is provided to assist generally in the selection of equipment.
Responsibility for selection and specification of our equipment must however remain
thatofourcustomerandanyexpertsorconsultantsconcernedwiththeinstallation(s).
Please note: that we do not therefore accept any responsibility for matters of
designselectionorspecification,fortheeffectivenessofaninstallationorsystem
containingoneofourproductsunlessspecificallyrequestedtodosoinwriting.
AllgoodsaresoldsubjecttoourConditionsofSalewhicharesetoutattherearofthis
specification. IntheinterestofcontinuouslyimprovingtheStainlessLiterange,Gledhill
BuildingProductsLimitedreservetherighttomodifytheproductwithoutnotice,and
in these circumstances this booklet,which is accurate at the time of printing,should
be disregarded. An updated set of Instructions will be produced and supplied with
new appliances and will be made available for other appliances on request.
A KIWA product approved to comply with all relevant parts of the
Building Regulations and Water Supply (Water Fittings) Regulations.
Visitwww.kiwa.co.ukformoreinformation.
StainlessLiteisproducedunderanISO9001:2008QualityManagementSystem
approved by BSI.
Benchmarkplacesresponsibilitiesonbothmanufacturersandinstallers.Thepurposeisto
ensure thatcustomers areprovided withthe correct equipmentfor their needs,that itis
installed,commissionedandservicedinaccordancewiththemanufacturersinstructions
by competent persons and that it meets the requirements of the appropriate Building
Regulations.The Benchmark Checklist can be used to demonstrate compliance with
BuildingRegulationsand shouldbeprovidedtothecustomerforfuturereference.
Installers are required to carry out installation, commissioning and servicing work
in accordance with the Benchmark Code of Practice which is available from the
Heating and Hot Water Industry Council who manage and promote the Scheme.
Visitwww.centralheating.co.ukformoreinformation.

Page 3
Maintenance
Modifications should not be made to this
product. Replacement parts, including
immersion heaters,should be purchased from
Gledhill Building Products Limited, or agents
approvedbythem.Unventedhotwaterstorage
vessels need regular routine checks,and these
aredetailedbelow. Itisforthisreasonthat this
manual must always be left with the Stainless
Lite.
It is essential that these checks be carried out
atthetimeofboilermaintenancebyaqualified
installer:
1. Manually open the relief valves in turn,and
check that water is discharged from the
valves and runs freely through the tundish
and out at the discharge point. Ensure that
the valves re-seat satisfactorily. (Note - the
water may be very hot).
2. It is important to check that the discharge
pipework is carrying the water away
adequately. Check for blockages etc. if it is
not.
3. Turn the mains water off and remove and
clean the strainer element in the Pressure
ReducingValve.
4. Checkthechargepressureintheexpansion
vessel and repressurise if required
5. Re-fill the system and ensure that all relief
valves have re-seated.
6. The Benchmark Service Record should be
updated at each service.
7. Checkthewaterpressuredownstreamofthe
combinationvalveis bar in static condition.
8. Check and if necessary, descale the heat
exchanger in hard water areas ie. above
200ppm (mg/l).
Note:
Thecylinderisfactoryfittedwithatemperature
&pressurereliefvalvethatmustnotbeusedfor
any other purpose or removed.
The cylinder is factory fitted with immersion
heaters with thermal cut outs. Immersions
without thermal cut outs must not be fitted.
Manufacturer: GledhillBuildingProductsLtd
Maximum inlet pressure to
Pressure reducing valve 12 bar
Operating pressure (PRV setting) 3 bar
Expansion vessel charge pressure 3 bar
Expansion relief valve setting 4.75 bar
Opening pressure of P &T Relief Valve 6 bar
Opening temperature of P &T ReliefValve 95°C
Energy cut-out thermostat setting 80°C
Max.working pressure - Primary heat exchanger (Indirect models) 6 bar
Max.working pressure - Solar heat exchanger (Solar models) 10 bar
Immersion heater rating 3kW,240V AC
All cylinders are manufactured in accordance with the requirements of BS EN 12897
Thetundish mustbe positionedsothat itis visible tothe occupantand is awayfrom
electrical devices.
Components supplied with Stainless Lite:
• Cold water inlet PRV combination valve/expansion relief
• Pressure and temperature relief valve
• Control thermostat
• Energy cut-out thermostat
• Energy cut-out motorised valve (indirects only)
• Tundish
• 3kW Immersion heater
• Expansion vessel/mounting bracket/flexible hose
• Technical/user product literature
(Note:Two immersion heaters are supplied with the direct Stainless Lite)
Inanysituationwherethevolumeofheatedpipework(eg.secondarycirculation
pipes or manifold pipework for multiple units) exceeds 10 litres, then an
additionalexpansionvesselmustbefittedtoaccommodatetheextraexpansion
volume.
Handling Before Installation
StainlessLitemustbehandledwithcareandstoredthecorrectwayupinadryplace.
Anymanualhandling/liftingoperationswillneedtocomplywiththerequirementsof
the Manual Handling Operations Regulations issued by the H.S.E.The appliance can
bemoved usingasack truck on the rearface although careshouldbe taken and the
route should be even.Inapartment buildings containing anumber ofstoreys wewould
recommendthattheappliancesaremovedverticallyinamechanicallift.If it is proposed
touseacrane,expertadviceshouldbe obtainedregardingtheneedforslings,lifting
beams etc.
A specific manual handling assessment is shown in Appendix B at the rear of this
manual.
DESIGN
DESCRIPTION

Page 4
DESCRIPTION
Stainless Lite is a range of unvented hot water storage cylinders, manufactured in
the latest high quality duplex stainless steel.They are designed to provide mains
pressure hot water and are supplied as a package which complies with Section G3
of the Building Regulations. The appliance is extremely well insulated using high
density HCFC free foam insulation with an ozone depleting potential (ODP) of zero
andaglobalwarmingpotential(GWP)of1. Itisfittedwithallnecessarysafetydevices
and supplied with all the necessary control devices to make installation on site as
easy as possible.
Stainless Lite Heat Pump (HP) models:
The Stainless Lite HP is an unvented hot water storage cylinder fitted with two high
efficiency internal primary heat exchangers especially designed for use with heat
pump systems.These two heat exchangers can be connected in parallel to the heat
pump circuit when a solar thermal system is not installed.When both heat pump
and solar thermal systems are installed,the top heat exchanger is connected to the
heat pump circuit and the bottom heat exchanger is connected to the solar circuit
a shown in figure 2.
All Stainless Lite HP models are fitted with 3kW (230Vac, 50Hz) immersion heater
for raising the temperature of the stored water to about 60°C after the heat pump
heating cycle if necessary.The technical details of the Stainless Lite HP models are
listed in table 1.
Important notes:
1. AllStainlessLiteHPmodelsaresuitableforbothopenventedandsealedprimary
systems.
2. Whenusedwithasealedprimaryheatingsystem,theheatpumpmustincorporate
its own over heat thermostat.
3. Stainless Lite HP models must not be used with solid fuel boilers or steam as the
heat source.
4. Heatpumpscannormallyonlyheatthedomestichotwatertobetween45–50°C,
thereforeprovisionshouldbemadetoperiodicallyheatthecylindertoabout65°C
to prevent growth of legionella.
5. The cold supply elbow c/w drain tapping must be fitted as shown in figures 1 &
2.A flexible hose can then be connected to the drain tapping and providing the
hoserunsbelowthelowestlevelofthecylinder,thenallthewatercontentcanbe
drained out by the symphonic action.
DESIGN
DESCRIPTION

Page 5
L
H
K
N
D
F
J
A
I
G
M
C
E
40
,00
º
45,00º
35,00º
2
5,
0
0º
15
,0
0
º
NOTES
1. Not all models - see
table 1.
2. Recovery times based
on Primary Coil/I.H.duty
(ie.assumes the boiler
output is adequate).
3. All connections
are supplied with
compression fittings
for direct connection to
copper pipework.
1. Measured at 0.25 l/s primary flow rate 2. Measured at 0.25 l/s primary flow rate and at 82°C flow temperature
Table 1
Stainless Lite HP Model HP180IND HP210IND HP250IND HP300IND HP400IND
Capacity - total volume litres 180 210 250 300 400
Volume heated by IH litres 113 135 160 195 270
Dedicated solar volume litres 65 75 90 105 130
Standing heat loss rate kWh/24h 1.40 1.60 1.75 1.93 3.33
Weight- empty/full kg 33/213 38/248 43/293 49/349 61/461
Pressure regulating valve setting bar 33333
Expansion relief valve setting bar 4.75 4.75 4.75 4.75 4.75
Temperature setting (P&T valve) °C 90 90 90 90 90
Pressure setting (P&T valve) bar 6.0 6.0 6.0 6.0 6.0
Expansion vessel size (volume) litres 18 24 24 35 2 x 24
Expansion vessel initial charge pressure bar 2.25 2.25 2.25 2.25 2.25
Height A mm 1295 1483 1733 2020 2040
Diameter B mm 550 550 550 550 630
22mm secondary return C mm - 1127 1377 1577 1592
22mm compression cold feed D mm 442 442 522 522 557
P &T valve E mm 1053 1241 1491 1777 1784
22mm solar return - bottom coil F mm 223 223 223 223 238
22mm solar flow - bottom coil G mm 352 352 472 472 548
28mm primary return - top coil H mm 467 542 647 742 641
28mm primary flow - top coil I mm 1072 1232 1467 1562 1791
Dual CT & OHT pocket - 1 top J mm 732 837 962 1092 1076
Dual CT & OHT pocket - 2 bottom K mm 419 419 539 539 651
Solar sensor pocket - 1 top L mm 882 1000 1180 1367 1382
Solar sensor pocket - 2 bottom M mm 203 203 262 262 334
3kW immersion heater height N mm 457 522 607 702 640
Surface area of solar heater coil m20.68 0.68 0.97 0.97 1.27
Solar coil pressure loss 1bar 0.191 0.191 0.241 0.241 0.31
Primary heat exchanger surface area m21.36 1.56 1.94 2.04 2.91
Primary heat exchanger thermal rating 1kW 24.3 26.2 27.5 34.2 47.2
Primary heat exchanger pressure loss 1bar 0.048 0.054 0.060 0.019 0.027
Heat up time from 15°C to 60°C 2min 33 41 44 48 49
Recovery time after 70% draw-off 2min 21 26 30 32 38
DESIGN
TECHNICAL INFORMATION

Page 6
7
9
3
11
2
9
6
12
13
1
8
4
5
10
Stainless Lite HP
Basic Appliance
1. Hot water draw off (22mm) compression
2. Temperature&pressurereliefvalve95°/6bar
3. Hot water secondary return 22mm
(not fitted to smaller sizes,see table 1)
4. Immersion heater 1¾”BSP 3kW
5. 22mm cold supply
6. Thermostat pocket (22mm)
7. Primary return (28mm)
8. Primary flow (28mm)
9. Dual control/Overheat stat & solar
thermostat pocket
10. Solar coil return to panel collector (22mm)
compression
11.
Solarcoil flowfrom panel(22mm)compression
12. Solar thermostat pocket
13. Drain off
Component kit supplied separately
A. Combinationinletgroupincorporatingpressure
reducing valve, strainer, check valve, balance
cold take off point,expansion relief valve and
expansion vessel connection points.
B. Potableexpansionvesselsc/wflexiblehose
and wall bracket
C. Tundish
D. Dual control thermostat and combined
overheat thermostat (x2)
E. Two port (22mm) zone valve for
primary circuit
F. Wiring junction box for primary system
Typical arrangement of component kit shown fitted to the appliance for clarity
Pipework to be supplied and fitted by installer.
DESIGN
SYSTEM DESIGN

Page 7
General Design Considerations
The cupboard footprint needs to be at least
650mmsquareforunitsupto300litres,730mm
for 400 litre units.
The base chosen for the cylinder should be level
and capableof supporting the weight of theunit
when fullof wateras shownin General Data. The
discharge pipework for the safety valves must
have a minimum fall of 1 :200 from the unit to a
safedischargepoint.Allexposedpipeworkshould
beinsulatedandtheunitshouldNOTbefixedina
locationwherethecontentscouldfreeze.
The pipe connecting the boiler flow to the
appliancemustnotbelessthan22mmcopper
or equivalent.
MainsWater Supply
Existing properties with a 15mm supply will be
satisfactory provided the local mains pressure
is good, but should be confined to single
bathroomproperties. Fornewpropertieswhere
simultaneousdemand isrequiredtomore than
one bathroom or a bathroom and one or more
en-suites,the communication and service pipe
intothedwellingshouldbeaminimumof22mm
(usually in the form of a 25mm MDPE supply).
The minimum recommended static pressure
to operate a Stainless Lite domestic system is 3
bar. There should be a flow of at least 30 litres
perminuteoraboveavailableintotheproperty.
Normally Stainless Lite provides well in excess
of 40 litres/min in most conditions. Flow rates
for ALL mains pressure systems are subject
to district pressures and system dynamic loss.
Particularly on larger properties with more
than one bathroom, the pipe sizes should be
calculated in accordance with BS6700.
I.V.
Combination Valve
I.V.
IftwoStainless Litesarecoupledtogether thesecondaryinletand outletpipes must
be balanced.The units must be fitted on the same level.
Note: No valves must be fitted between the expansion vessel and the storage
cylinder(s).
INSTALLATION
INSTALLATION

Page 8
INSTALLATION
Model Selection
The suggested model sizes shown in the table
opposite are based on a typical daily hot water
usage and on the assumption that the heat
pumpwillheatthedomestichotwatertoabout
50°C.Forhigherspecification,anincreaseofone
model size should be considered.
When selecting a solar model,it is important to
checkthededicatedsolarvolumeshownintable
1issuitableforthetotalfloorareaofthedwelling
and/ornet area of thesolar collectors to ensure
compliance with the Building Regulations.
WhenStainlessLiteHPisconnectedtobothheat
pump and solar thermal systems, then during
the winter period the solar contribution will
be negligible and the heat pump will only heat
about 65% of the cylinder volume.This should
betakenintoaccountwhenselectingthemodel.
Stainless Lite HP Model Selection Guide
Dwelling type Suggested model
Number of
bedrooms
Number of
bathrooms and
shower rooms
Without solar
heating system (1) With solar heating system (2)
1-3 1 bathroom HP180IND HP180IND (FA=50m2)
2-3 1 bathroom +
1 shower room HP180IND HP210IND (FA=65m2)
2-3 1 bathroom +
2 shower rooms HP180IND HP250IND (FA=85m2)
2-4 2 bathrooms +
1 shower room HP210IND HP300IND (FA=110m2)
2-4 2 bathrooms +
2 shower rooms HP250IND HP400IND (FA=150m2)
3-5 2 bathrooms +
2 shower rooms HP300IND –
4-5 2 bathrooms +
3 shower rooms HP400IND –
Notes
1 Both top and bottom heat exchangers connected to heat pump circuit
2 Top heat exchanger connected to heat pump circuit and bottom heat exchanger
connected to solar circuit.
3 FA= Maximum floor area of the dwelling for compliance with the Building Regulations
INSTALLATION

Page 9
INSTALLATION
Stainless Lite HP/Heat Pump Selection Guide
The table above can be used to match heat pumps to heat pump cylinders.
To use, first obtain the maximum flow rate from the heat pump manufacture’s
instructions,match thisto theflow ratesinsection1 andfollowthis flowrate’scolumn
down through the other sections.
Section 2 showsthe velocity in thepipe work ofdifferent diametersat this flow rate.A
maximumflowvelocityof1m/shasbeenchosentolimitflownoise.Usethissection to
choose the correct pipe diameter.
Stainless Lite HP/Heat Pump Selection Guide
1 - Flow rates in various units for comparison with heat pump manufacturers data
m3/h 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25
l/min 8.33 12.50 16.67 20.83 25.00 29.17 33.33 37.50 41.67 45.83 50.00 54.17 58.33 62.50 66.67 70.83
l/sec or kg/s 0.14 0.21 0.28 0.35 0.42 0.49 0.56 0.63 0.69 0.76 0.83 0.90 0.97 1.04 1.11 1.18
2 -Velocity in pipe (limited to 1 m/s maximum) for pipe sizing
m/s in 22mm 0.37 0.55 0.73 0.91 - - ----------
m/s in 28mm 0.23 0.34 0.45 0.56 0.68 0.79 0.90 ---------
m/s in 35mm 0.14 0.22 0.29 0.36 0.43 0.51 0.58 0.65 0.72 0.79 0.87 0.94 - - - -
m/s in 42mm 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85
3 - Operating power of heat exchanger suitable for cylinder based on a 5 degree temperature difference
kW @ 5K dt 3-4 4-6 5.5-8 7-10 8-12 10-14 11-16 13-18 14-20 16-22 17-24 18-26 20-28 21-30 23-32 24-34
180HP ----------
180HP + Sol ------
210HP ---------
210HP + Sol -----
250HP ---------
250HP + Sol -----
300HP -----
300HP + Sol -
400HP -----
400HP + Sol -
4 - Pressure loss (bar) for each flow rate above in the available coil combinations
180HP 0.010 0.027 0.053 0.092 0.143 0.207 0.286 0.381 0.491 0.618 0.763 0.927 1.109 1.310 1.532 1.774
180HP + Sol 0.003 0.008 0.017 0.031 0.049 0.073 0.103 0.140 0.183 0.234 0.292 0.359 0.434 0.518 0.612 0.715
210HP 0.017 0.040 0.074 0.118 0.173 0.239 0.316 0.405 0.505 0.617 0.741 0.877 1.025 1.184 1.356 1.540
210HP + Sol 0.013 0.033 0.064 0.107 0.164 0.234 0.318 0.417 0.532 0.663 0.810 0.975 1.156 1.356 1.574 1.810
250HP 0.006 0.015 0.028 0.045 0.067 0.093 0.124 0.159 0.200 0.245 0.295 0.350 0.410 0.475 0.545 0.620
250HP + Sol 0.004 0.011 0.021 0.036 0.054 0.077 0.105 0.138 0.176 0.218 0.267 0.321 0.380 0.445 0.517 0.594
300HP 0.008 0.019 0.036 0.058 0.086 0.120 0.160 0.206 0.259 0.318 0.384 0.457 0.536 0.623 0.716 0.816
300HP + Sol 0.004 0.014 0.031 0.058 0.098 0.152 0.223 0.312 0.421 0.553 0.708 0.890 1.100 1.339 1.610 1.915
400HP 0.004 0.010 0.018 0.030 0.044 0.062 0.083 0.108 0.136 0.167 0.202 0.241 0.283 0.329 0.379 0.432
400HP + Sol 0.008 0.018 0.031 0.049 0.070 0.094 0.123 0.155 0.190 0.230 0.273 0.319 0.370 0.423 0.481 0.542
INSTALLATION
Section3showsthemaximumoperatingpower
ofthecoilsinthecylinder. Shadedsquaresshow
the range of operating powers suitable for a
cylinder in either of its set ups.
Section 4 shows the pressure loss across the
coils at this flow rate for all cylinders in both
configurations.

Page 10
INCOMING COLD SUPPLY
M
DC
DC
DC
TO
EXTERNAL
TAP
SINK
WATER SOFTENER (IF NECESSARY)
WM or DWM
WHB W.C.
DC
DC
SH
DHW
WHB
WC BATH
SCV SCV
P&T
ERV/NRV
PRV
DCV
Note:
Cold supplies to single taps must be
taken from the mains cold water
system.
Cold supplies to mixer taps must be
taken from the balanced cold water
connection on the combination
valve.
General Restrictions
a. The highest hot or cold water draw off point should not exceed 10 metres above
the Pressure ReducingValve.
b. AnascendingspraytypebidetoranyotherappliancewithaClass1back-syphonage
risk requiring a type A air gap should not be used.
c. StainlessLite should notbe used where steamis the primary heatingmedium,or
in a situation where maintenance is likely to be neglected.
d. Unvented cylinders are not suitable for use with solid fuel boilers.
e. Ifthe supply to the mixer fittings(other than a dual outlet type) is not taken
fromthebalancedsupplythesystemwillbecomeoverpressurizedandcause
the pressure relief valve to discharge. Over time this could also cause the
premature failure of the appliance itself which will not be covered by the
warranty.
f. In larger properties with a number of bathrooms/en-suites and long pipe runs
we would recommend that the balance cold supply is provided with its own
pressure reducing valve and is not taken from the balanced cold connection on
thecombinationvalve. Inthiscaseitwillalsobenecessarytofitasmallexpansion
vesselonthebalancedcoldwatersystemtoaccommodatethepressurerisecaused
by the increase in temperature of the balanced cold water.
g. Checktheperformancerequirementsoftheterminalfittingswith regardtoflow/
pressure are suitable.
Shower Fittings
Aeratedtapsarerecommendedtopreventsplashing.Anytypeofshowermixingvalve
can be used as long as both the hot and cold supplies are mains fed. However, all
mainspressuresystems aresubjectto dynamicchangesparticularlywhenother hot
andcoldtaps/showersareopenedandclosed,whichwillcausechangesinthewater
temperature at mixed water outlets such as showers. For this reason and because
these are now no more expensive than a manual shower we strongly recommend
the use of thermostatic showers with this appliance. These must be used in 3 storey
propertieswheretheimpactonpressure/temperatureofopeninganothertapinthe
system is greater than normal.The shower head provided must also be suitable for
mains pressure supplies.
Pipe Layout
Inallmainspressureinstallationsitisimportant
to remember that the incoming cold supply
mustbesharedbetweenallterminalfittings. It
isimportant that a 22mm supply is brought to
theapplianceanda22mmtake-offiscontinued
atleasttothebath. Iftherearetwobaths,28mm
pipeworkshould be considered. Onemetreof
smaller diameter pipework,or flow restrictors,
should be provided on the final connection to
all outlets so as to balance the water available.
In any event the distribution pipework should
generally be in accordance with EN806:1.
Plastic Pipework
This appliance is suitable for use with
plastic pipework as long as the material
is recommended for the purpose by the
manufacturerandisinstalledfullyinaccordance
with their recommendations.
Secondary Hot Water Circulation
Somemodelsarefittedwithasecondaryreturn
tapping as standard (see table 1 for details).
If fitted, an extra expansion vessel may be
necessary. Anon-returnvalveMUSTbeFITTED
nearthereturnconnection. Novalveorterminal
fitting should be installed between the non
return valve and the cylinder. (See schematic
arrangement on page 13.)
INSTALLATION
INSTALLATION

Page 11
15 mm
discharge
pipe
Expansion
relief valve
Typical Discharge Pipe Arrangement
Dotted line showing
alternative route with
single tundish being used
500 mm max.
P & T
Relief
Valve
300 mm
min.
22 mm metal pipe with continuous
fall up to 9m equivalent length (D2).
NOTES:
The discharge will consist of scalding
waterand steam. Asphalt, roofing felt
and non-metallic rainwater goods may
be damaged by such discharges.
It is not acceptable to discharge straight
into a soil pipe.
Discharge below
fixed grating
Fixed Grating
Trapped gully
Pressure & Temperature/expansion Relief
Valve Pipework
Thereliefvalveshouldbeinstalledtodischarge
in accordance with G3 of the Approved
Document of the Building Regulations and
should be piped to where it is visible,but will
not cause danger to persons or damage to
materials.
The following information is taken from
Approved Document G3 of the Building
Regulations and is provided to assist with
the design and installation of the discharge
pipework. However, the information is not
exhaustive and reference should always be
madetoApprovedDocumentG3oftheBuilding
Regulations.The final decision regarding any
arrangements rests with Building Control and
it is recommended that their advice is sought
if you have any concerns regarding this aspect
of the installation.
The two safety valves will only discharge
water under fault conditions. When operating
normally water will not be discharged.
The tundish should be vertical, located in the
samespace as the unventedhot water storage
system and be fitted as close as possible and
within 500mm of the safety device e.g. the
temperature relief valve.
Thedischargepipe(D2)fromthetundishshould
terminate in a safe place where there is no risk
to persons in the vicinity of the discharge,be
of metal and:
a) Be at least one pipe size larger than the
nominaloutletsizeofthesafetydeviceunless
its 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
leasttwosizeslargerthanthenominaloutlet
size of the safety device, between 18 and
27mat least 3 sizeslarger,and soon. Bends
must be taken into account in calculating
the flow resistance. Refer to the table and
the worked example.
An alternative approach for sizing
discharge pipes would be to follow BS6700
Specification for design installation,testing
andmaintenanceofservicessupplyingwater
for domestic use within buildings and their
curtilages.
b) Have a vertical section of pipe at least
300mm long,below the tundish before any
elbows or bends in the pipe work.
c) Be installed with a continuous fall.
Worked Example
TheexamplebelowisforG1/2temperaturereliefvalvewithadischargepipe(D2)
having 4 elbows and length of 7m from the tundish to the point of discharge.
FromTable 1:
Maximum resistance allowed for a straight length of 22mm copper discharge
pipe (D2) from a G1/2 temperature relief valve is:9m subtract the resistance for
4 x 22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to:5.8m.
5.8mis less thanthe actual length of7mthereforecalculate thenextlargestsize.
Maximumresistanceallowedforastraightlengthof28mmpipe(D2)fromaG1/2
temperature relief valve equates to:14m.
As the actual length is 7m,a 28mm (D2) copper pipe will be satisfactory.
Table 1:Sizing of copper discharge pipe‘D2’for a temperature relief
valve with a G1/2 outlet size (as supplied)
Size of discharge
pipework
Maximum length of
straight pipe
(no bends or elbows)
Deduct the figure
below from the
maximum length for
each bend or elbow in
the discharge pipe
22mm Up to 9m 0.8m
28mm Up to 18m 1m
35mm Up to 27m 1.4m
INSTALLATION
INSTALLATION

Page 12
d) Itispreferableforthedischargetobevisibleatboththetundishandthefinalpoint
of discharge but where this is not possible or practically difficult there should be
clearvisibilityatoneorotheroftheselocations. Examplesofacceptabledischarge
arrangements are:
1. Ideally below the fixed grating and above the water seal in a trapped gulley.
2. Downward discharges at a low level;i.e.up to 100mm above external surfaces
suchascarparks,hardstandings,grassedareasetcareacceptableprovidingthat
wherechildrenplayorotherwisecomeintocontactwithdischarges,awirecage
or similar guard is positioned to prevent contact whilst maintaining visibility.
3. Dischargesatahighlevel;e.g.intometalhopperandmetaldownpipewiththe
end of the discharge pipe clearly visible (tundish visible or not) or onto a roof
capable of withstanding high temperature discharges of water and 3m from
any plastic guttering systems that would collect such discharges.
4. 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
installationcanbetracedreasonablyeasily. Thesinglecommondischargepipe
shouldbeatleastonepipesizelargerthanthelargestindividualdischargepipe
to be connected. If unvented hot water storage systems are installed where
dischargesformsafetydevicesmaynotbeapparenti.e.indwellingsoccupiedby
blind,infirmordisabledpeople,considerationshouldbegiventotheinstallation
of an electronically operated device to warn when discharge takes place.
Safety
ThesafetydevicessuppliedorfittedonanStainlessLiteareselectedfortheirsuitability
forthe temperaturesandpressuresinvolved. Theymustnotbechanged,removedor
by-passedanditisessentialthatonlygenuinereplacementpartssuppliedorapproved
by Gledhill Building Products Limited are used.This includes the immersion heaters,
whichmustincorporateanenergycut-out.Allpartsareavailabletoapprovedinstallers
from Gledhill Building Products Limited, Sycamore Estate, Squires Gate, Blackpool
(Telephone [phone]).
Stainless Lite HP model without
solar heating system
P&T Relief Valve
Tundish
Hot Outlet
To Drain
PRV
ERV NRV
Stop
Tap
Kitchen
Cold
Tap
Combination
Valve
Balanced
Cold
Outlets
Expansion
Vessel
Heat Pump
Return
Secondary
Return Circuit
Non Return
Valve
Pump
Stainless Lite HP model with
solar heating system
Secondary
Return Circuit
Heat Pump
Flow
P&T Relief Valve
Tundish
Hot Outlet
To Drain
PRV
ERV NRV
Stop
Tap
Kitchen
Cold
Tap
Combination
Valve
Balanced
Cold
Outlets
Expansion
Vessel
Heat Pump
Return
Solar Return
Solar Flow
Non Return
Valve
Pump
Heat Pump
Flow
Combination Inlet Group
Combines elements 1,2 and 3 below.
1. PressureReducing Valve -This must be fixed
near the cylinder. The cold water supply to
anymixertaps/showersmustbetakenfrom
thecoldwatertappingofthisvalvetoensure
balancedhotandcoldpressures. Thisvalve
isfactorysettoensurethecorrectoperating
pressure for the Stainless Lite.
2. Non Return Valve - This is integral with the
pressurereducingvalvetopreventbackflow
of hot water towards cold water draw off
points.
3. ColdWaterExpansionReliefValve-Thissafety
deviceispresetatthefactoryandwillrelieve
excesscoldwaterpressure resultingfrom a
fault condition.
INSTALLATION
INSTALLATION

Page 13
Safety
Cut-out
Thermostat
Immersion HeaterWiring
E
L
N
Temperature/pressure ReliefValve
This safety device is also pre-set at the factory and relieves before the temperature
reaches 100°C.It is also a Pressure ReliefValve,and is pre-set to 6 bar.
Immersion Heater
All stainless Lite HP models are fitted with a 3kW immersion heater so that the store
temperature can be raised above that which the heat pump provides,to boost the
hot water performance if necessary and to protect against legionella eg.once a day
or once a week.
These are 3kW 240V AC heaters and incorporate a thermostat and a manually reset
energycut-outwhichoperatesat80°C. Theyhaveincalloyelements toprolongtheir
life expectancy in aggressive water conditions.
ExternalwiringtotheimmersionheatersmustbeinaccordancewiththerelevantIEE
WiringRegulationsandthecircuitmustbeprotectedbyasuitablefuseandadouble
pole isolating switch.
Thecorrectmethodofterminatingthewiringtotheimmersionheaterisshownopposite.
The operation of the boost immersion heater can also be controlled by means of an
independenttimeswitchasshownschematicallybelow.The‘ON’timesettingsonthe
immersionheatershouldbebetween30-60minuteslaterthanthe‘ON’timessetfor
the hot water programmer channel.
For example if the hot water is programmed to come on between 0600 - 0900 and
1700-2200thentheimmersionheatersettingshouldbe0640-0900and1740-2200.
This will give hot water heating by heat pump a priority.
Line Strainer
This is integral within the combination inlet group to reduce the likelihood of
contaminantsfoulingthevalveseat. Followinginstallation thisline strainer mustbe
cleaned and replaced. This needs to be carried out on a regular basis.as part of the
annual maintenance/service check.
Tundish
Thisis toallowthe dischargefrom anyReliefValvetobe seen. It mustbefitted away
from any electrical devices. See page 13 for discharge pipework details.
Typical schematic wiring diagram for the boost immersion heater
using immersion programmable immersion heater timer.
Safety
The immersion heaters must be earthed and
they must be isolated from the mains before
the cover is removed on every occasion.
Replacement immersion heaters should be
obtained from Gledhill Building Products
Limited.
Control/overheat Dual Thermostats
Care must be taken to ensure that the solar
probes are fully inserted into the pockets
provided.
INSTALLATION
INSTALLATION

Page 14
Heating And Primary Systems
Although the heat pump and the primary
heatingsystemshouldbesizedandinstalledin
accordance with BS 5449 the following should
also be taken into account during the design
and installation phase.
Theheatpumpsnormallyoperateatlowerflow
temperatures; typically 45 – 55°C compared
with 75 – 80°C for the boilers. Therefore if
traditionalradiatorsareusedthen,theseshould
beoversizedinaccordancewiththeheatpump
manufacturers recommendations.
Foroptimumefficiency(i.e.COPofaheatpump),
low temperature under floor heating system
should be considered.
The heat pumps normally operate at lower
temperature difference between flow and
return compared with the traditional boilers
and therefore when sizing the pipework heat
pumpmanufacturersrecommendationsshould
be taken into account.
Safety
Stainless Lite HP is fitted with a combined
temperature and pressure relief valve to cope
withanyincrease intemperatureandpressure
in the cylinder above the design limits, when
used with heat sources up to 45kW total
output.This is the maximum heat input to the
cylinderallowedbysectionG3ofthe‘Approved
Document G’of the Building Regulations.
The heat supply to the cylinder and hence the
temperature of the stored water should be
controlled as outlined below:-
• Heat supply from the primary heat source
i.e.heat
The 2-port spring return motorised valve
suppliedshouldbefittedadjacenttotheunit
and controlled by the cylinder thermostat
(combinedcontrolandoverheatthermostat)
supplied with the unit.The motorised valve
andthethermostatmustbewiredsothatthe
motorisedvalveswitchesoffwheneitherthe
controlthermostatcontactbreakswhenthe
set temperature is reached or the overheat
thermostatcontactsbreakwhenanoverheat
condition develops.The operation of the
heat source should be controlled via the
auxiliary switch of the motorised valve.
Itisimportanttofollowthewiringdiagrams
in the wiring section of these instructions.
Schematic OpenVented Primary System
Heat Pump
Pump
150mm max.
Warming/Overflow
Pipe
F & E Cistern
Minimum
distance as
required by
heat pump
manufacturers
instructions
Motorised Valve
Motorised Valve
(Energy cut-out)
Schematic Sealed Primary System
Motorised Valve
Motorised Valve
(Energy cut-out)
Expansion
Vessel
Gauge
Safety Valve
Pump
Heat Pump
INSTALLATION
INSTALLATION

Page 15
Solar Heating System
StainlessLiteHPissuitableforusewithcombinedheatpumpandsolarthermalheating
systems.Allcomponentsinasolarprimarycircuitmustbemarkedoridentifiedinsuch
a way that their design pressure and temperature can be readily determined
A safety device (pressure relief valve) to control the risk of over-pressure in system
components should be fitted. A termination from a safety pressure device should
minimise the risk of damage to persons or materials.Suitable locations are a high
temperaturereceptacle,aninternalgullyorelseissueexternallyatgroundlevel.High
levelterminationfromwallsoronroofscouldcauseinjurytopeopleoranimalsbelow
if the valve were to release scalding water and steam.
The pipe leading to the safety device and the collector should be of rigid and non-
deformable construction,without any possibility of restriction or disclosure by any
other fitted component.
Amoredetaileddiagramofourrecommendedarrangementforatypicalsolarsystem
is shown on page 15.
This provides all the necessary controls and safety devices necessary for the solar
systemi.e.thetwoport zonevalveiswiredas anenergycutoutand thepump/valve
will only allow heat transfer as required under control of the solar controller.
Stainless Lite HP system configuration with solar thermal heating system
Solar
pumping
station
Solar circuit
zone valve
Central heating
flow and return
Central heating zone valve
Heat pump
PRV
Expansion
vessel
Hot water zone valve
System pump
PRV
Primary circuit
sealed system kit
• Sealed heating system
A heat pump selected must be suitable for use in a sealed heating system which
mayhaveworkingpressureofupto3.0bar andit mustbe fittedwithan overheat
temperature cut-out device.
Unvented (i.e.sealed primary circuits may be filled or replenished by means of a
temporary connection between the circuit and a water supply pipe provided a
WRC‘Listed’double check valve and filling loop or some other no less effective
backflow prevention device is permanently connected at the inlet to the circuit
and the temporary connection is removed after use.
Alternatively,aCAdevicecanbeusedwhichwillallowthesystemtobepermanently
connected to the cold mains supply.The primary system can then be topped up,
when required, in the same way as an open vented system fitted with an F&E
cistern.
• Open vented heating system
It is essential that the primary circuit
between the boiler and the Stainless Lite is
pumped and that the cold feed and open
ventconnections are positionedto prevent
pupoverintothefeedandexpansioncistern
andtoensurethattheopenventiscorrectly
sized.
A typical arrangement of the open vented
system is shown in figure _.
The pocket provided for the Dual Thermostat
also includes the facility to accommodate an
8mm diameter sensor which, with the sensor
located in the solar collector (or in the flow
pipe immediately adjacent to the collector),
will provide the information required by the
solar controller.
Note:Ifthemotorisedvalveisnotusedthen
any factory built hydraulic station for solar
useMUSTbefittedwithsuitablenon-return
valves in both flow and return pipes to
prevent gravity circulation when the pump
is not running.
INSTALLATION
INSTALLATION

Page 16
19876543210
12 3456 78
S1 S2 S3
201918171615141312
LNR1R2 NN
T
S1
S1
1 bar
Solar
Pumping
Station
Solar Coil
TWO PORT
ZONE VALVE
AB
C12C1
+ C
o
+ C
o
LN
230 VAC 5 amp
Mains Supply
Dual Thermostat
Gledhill Stainless Lite
Unvented Cylinder TAnti Gravity
Check Valve
Pressure
Relief Valve
Anti Gravity
Check Valve
Standard 10 way
wiring junction box
(Not supplied)
This valve must be fitted on
the return to the solar panels
and be suitable for higher
temperatures operation
(Not
supplied)
No isolation valve
should be installed
between the solar
circuit and the safety
valve (pressure relief
valve)
Solar Controller
Schematic Showing SolarWiring Requirements
INSTALLATION
INSTALLATION

Page 17
INSTALLATION
INSTALLATION

Page 18
Connections can come loose in transit, and all should be checked before
installation.
Ensurethattheimmersionheatersettingis60°Candthatthe wiringisinaccordance
with the diagram.
Checkthepressureontheairsideoftheexpansionvessel=3bar. Thismustbedone
when the volume in the cylinder is cold.
Checkthatthedraincockisclosed,andopenallthecoldandhotwatertapsandother
terminalfittings. Allowthesystemtofillwithwater,andtorununtilthereisnoairleft
in the system. Close the taps and inspect the system closely for leaks.
Manually open the ReliefValves one by one and check that water is discharged and
runfreelythrough the tundish and out at the discharge point. Thepipeworkshould
accept full bore discharge without overflowing at the tundish,and the valve should
seat satisfactorily.
Allowthecylindertoheattonormalworkingtemperature,thenthoroughlyflushthe
domestic hot and cold water pipework through each tap.
NOTE: If this appliance is to be installed in other than a single domestic dwelling ie.
in an apartment block or student flats etc.,the hot and cold water system will need
to be disinfected in accordance with BS6700 and theWater Regulations.
Because the Stainless Lite appliance is stainless steel, the use of chlorine as the
disinfectionagentcancausedamageunlesstheapplianceisadequatelyflushedand
refilledwiththemainswaterimmediatelyoncompletionofthedisinfectionprocedure.
Damage caused through a failure to do this adequately will not be covered by the
warranty.
For the above reasons we recommend the use of a non chlorine dased disinfectant
suchasFernoxLPSteroxasmanufacturedbyCooksonElectronicswhencarryingout
disinfection of systems incorporating these appliances.
Removethefilterfromthecombinationinletgroupcleanandreplace. Refillthesystem
and open all hot taps until there is no air in the pipe work. ENSURE CYLINDER IS
DRAINED PRIORTOCHECKING OR REMOVING FILTERFROMTHECOMBINATION
INLET GROUP.
Allowthecylindertoheattonormalworkingtemperaturewithwhateverheatsource
isto be used,andcheck again forleaks. ThePressureReliefValve should not operate
during the heating cycle.
The boiler/heating systems should be filled
and commissioned in accordance with good
practicefollowingtheguidanceinBS5449/the
boilermanufacturersinstructions.Thisincludes
adequatelyflushing the system to removeany
debris that may have been introduced during
installation/maintenance.
NOTE:ThisapplianceiscoveredbyBENCHMARK
andtheservicerecordmustbecompletedafter
commissioning and after every maintenance/
service visit.
IMPORTANT - DRAIN DOWN PROCEDURE
1 Switch off both the heat pump and the immersion heater
2 Open the nearest hot tap and run all hot water until cold
3 Close the incoming cold main at the stop tap
4 Holdopenthepressureandtemperaturereliefvalveuntilwaterstops
discharging into the tundish
5 Open all the taps in the property
6 Open the drain cock and immediately hold open the pressure and
temperature relief valve again until the cylinder is empty
INSTALLATION
COMMISSIONING

Page 19
YourStainlessLiteunventedcylinderisautomaticinnormaluse,butrequiresroutine
maintenance which is normally carried out at least annually along with the boiler
service.The maintenancemust becarriedout bya suitably competenttradesperson
who is qualified to work on unvented cylinders.The checks/work needed are listed
in the maintenance part of these Instructions.
The heat pump control thermostat should switch to the hot water zone valve
before the heat pump starts to cycle on its internal thermostats.For example if the
maximum primary flow temperature available from the heat pump is 55°C,then the
control thermostat should be set to 48°C.(This setting should not be changed by
the occupant.)
When initially opening the taps, a small surge in flow may be experienced, which
disappears as the pressure in the system stabilises.This is quite normal with these
types of systems and does not indicate a fault.
Insomeareasthe waterwillinitially appearcloudy,butwillquicklyclearwhen leftto
stand.This is nothing to be concerned about and is due to aeration of the water.
WARNING-Ifwaterisseenflowingthroughthetundish,thisindicatesafaultcondition
which needs action.
If the discharge is hot and continuous,turn the boiler and/or the immersion heaters
off,but do not turn off the cold water to the appliance until the discharge is cold.
Note:The discharge may stop by itself as the discharge cools.
If the discharge is cold and intermittent, no immediate action is needed but this
indicates a problem with the expansion vessel.
However,inbothcasesyoumustcalltheregisteredinstaller/asuitablyqualified,
competent tradesperson,advise them that you have an unvented cylinder and
request a maintenance visit.
DONOT,atanytime,tamperinanywaywiththesafetyvalvesoroverheatthermostats/
wiring.
USER INSTRUCTIONS
USER INSTRUCTIONS

Page 20
The Registered Installer is responsible for the safe installation and operation of the
system. Theinstaller must also make his customer awarethat periodic maintenance
of the equipment is essential for safety.
Maintenance periods will vary for many reasons. Gledhill Building Products Ltd
recommendamaximumof12monthstocoincidewithboilermaintenance. Experience
of local water conditions may indicate that more frequent maintenance is desirable,
eg,whenwaterisparticularlyhard,scale-formingorwherethewatersupplycontains
a high proportion of solids,eg,sand. Maintenance must include the following:
1. Check and clean filter
2. Manually check the operation of the temperature relief valve.
3. Manually check the operation of the expansion relief valve.
4. Checkdischargepipesfromtemperatureandexpansionreliefvalvesarefreefrom
obstruction and blockage and are not passing any water.
5. Check the condition and if necessary descale the heat exchangers in hard water
areas.
6. Check that water pressure downstream of pressure reducing valve is within the
manufacturers limits.
7. Check operation of motorised valve.
8. Checkthepressureontheairsideoftheexpansionvessel.Thismustbedonewhen
the volume in the cylinders is cold.
9. Checkandadvisethehouseholdernottoplaceanyclothingorothercombustible
materials against or on top of this appliance.
10.On completion of the work, fill in the Benchmark Service Record at towards the
back of this manual.
IMPORTANT NOTE
When draining down the appliance for any reason, the instructions
provided in the Commissioning Section MUST be followed to prevent
potential damage to the cylinder.
SERVICING AND MAINTENANCE
SERVICING AND MAINTENANCE