Potterton Mersey Super Quick guide

INSTALLATION AND SERVICE INSTRUCTIONS
Mersey Super
Gas Fired Water Heater
G.C. NO.52476 38
NON SPOUTED MULTIPOINT MODEL
FOR USE WITH NATURAL GAS
THE GAS SAFETY (INSTALLATION AND USE) REGULATIONS 1984.
"In your own interest, and that of safety, it is law that all gas appliances are installed by
competent persons, in accordance with the above regulations. Failure to install appliances
correctly could lead to prosecution."
Installation must be in accordance with the Building Regulations, Byelaws of the Water
Undertaking, and I.E.E. Wiring Regulations. It should be in accordance also with any
relevant requirements of the Local Gas Region and Local Authority and the relevant
recommendations of the following British Standard Codes of practice: BS 6891, BS
5440:1:2 and BS 5546.
LEAVE
THESE
INSTRUCTIONS
WITH
THE
USER
FOR
USE
ON
FUTURE
CALLS
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IMPORTANT
PLEASE READ THIS BOOK
BEFORE INSTALLING,
OPERATING OR SERVICING THIS APPLIANCE.
Page 1
1. INTRODUCTION - Page 2
The Main Mersey Super is a room sealed instantaneous water heater designed to supply
hot water to several outlets which may be situated in different rooms, but not necessarily at
the same time.
The pilot is lit by a piezo spark igniter: no batteries or electricity are required. The main
burners will automatically light when a domestic hot water tap is turned on and go out when
the tap is turned off.
This appliance is not suitable for use with a swivel spout.
ENERGY CUT-OFF DEVICE
This appliance contains an Energy Cut-Off Device that will shut down the gas supply to the
appliance if the water within the heat exchanger exceeds the anticipated temperature limit
after the hot water tap has been turned off - See Page 21.
VENTILATION
Being a room sealed appliance, the Mersey Super does not require an air vent in the room
or space in which it is installed.
Where this appliance is installed in a compartment, air vents to the compartment at both
high and low levels, should be provided for cooling.
Further guidance is given in BS 5440 Pt.2.
Position of Air Vent
High Low
In compartment which is ventilated to room 274 cm² 274 cm²
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GENERAL
IMPORTANT: The area of wall covered by the appliance must be flat.
The clearances required around the Flue Terminal are shown on the Flue Template
supplied with the Terminal Pack.
The appliance must be fitted on an external wall to allow the Flue Terminal to pass directly
through the wall to the outside air.
If the appliance is to be installed into a "SEDUCT" the minimum duct required is 228mm
(9in.) deep, 349mm (1 5½in.) wide.
This appliance may take the place of an existing appliance and will mount onto the original
flue terminal of any of the following: AVON, BRISTOL, MEDINA, MEDINA D/L, MEDWAY,
MERSEY, SEVERN 3, SEVERN 4, SEVERN 5 and TRENT.
Page 2
2. TECHNICAL SPECIFICATIONS - Page 3
42 in² 42 in²
In compartment which is ventilated to
outside 137 cm² 137 cm²
21 in² 21 in²
Finish White stoved paint with contrasting
chassis
Weight Packed 21.0 kg. (46.2 lb.)
Weight without Water 17.8 kg. (39.2 lb.)
Weight with Water 18.6 kg. (41.0 lb.)
Water Capacity 0.75 litre (0.17 gall.)
Input 30.3 kW (103,000 Btu/h.)
Maximum Output 22.7 kW (77,400 Btu/h.)
Flow Rates 6.5 1/mm at 50
0
C rise
Minimum pressure head requirement at water
heater * 1 bar (14.6 psi) under flow conditions
Maximum pressure head 13 bar (189 psi)
Gas group G 20
Burner injector (140ff) 1.2mm marking 120
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Notes:
* Additional external pipework and fittings may affect the resistance and must be taken into
account on installation.
** The nominal burner pressure should be 12.5 mbar and will only be obtained if the
appliance inlet pressure is correct at 20 mbar even when the appliance is running at full
heat input. The meter should be capable of passing 1 00ft
3
/h of natural gas plus the
requirements of any other gas appliances.
MINIMUM CLEARANCES
For ease of servicing, allow as much clearance as possible below the appliance.
If the appliance is to be installed in a cupboard, the ventilation openings in the cupboard
must
NOT
be
blocked
.
DO
NOT
USE
THE
CUPBOARD
FOR
STORAGE
.
Pilot injector 0.27mm marking A
Nominal burner pressure ** (maximum input) 12.5 mbar (5 in. w.g.)
Connections - Gas 15mm Copper Tail
15mm Compression
- Water
Balanced flues (telescopic) Wall thickness
available 100mm - 150mm (4in - 6in) - Part No
31/1
0321
150mm - 230mm (6in - 9in) - Part No
31/1
0322
230mm - 380mm (9in - 15in) - Part No
31/1
0323
380mm - 610mm (15in - 24in) - Part
No
0324
Flue Terminal Guard (Optional) Part No 10/1 0262
Above 60mm
Below 75mm
Sides 5mm (Each)
Front 220mm (To allow for removal of outer
case)
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Fig. 1
Page 3
3. INSTALLATION - Page 4
Fig. 2
A. LOCATION
1. If the appliance is to be fixed to a suitable existing terminal first isolate and remove the
old appliance. Leave the flue terminal in place. Retain the fixing nuts and washers. Make
good any damage to the brickwork or plaster around the terminal. Cut off the existing
pipework at a convenient point below the appliance.
2. If installing a new flue terminal, guidance is given on the template sheet supplied with the
terminal
pack
.
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NOTE: Where the appliance is to be installed into a SEDUCT the minimum duct required is
228mm (9in) deep, 349mm (15½ in) wide.
Fig. 3
3. Where the building regulations require it, a flue terminal guard should be fitted
symmetrically around the outer part of the flue terminal.
4. Unpack the water heater. Find the bags of accessories before discarding the packaging.
5. Slide off the bottom cover then remove the three screws securing the outer case and
carefully lift it off.
Fig. 4
6. Use the self adhesive discs supplied to cover the unwanted fixing holes in the back of the
new appliance as shown.
Page 4
INSTALLATION - Page 5
7. Fit the flue terminal sealing strip (packed separately in the carton) into the recess around
the
flue
aperture
in
the
back
of
the
appliance
.
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8. Lift the appliance into position, locating the flue outlet into the circular duct on the flue
terminal.
9. Secure with the appropriate nuts and washers.
Fig. 5
B. GAS CONNECTION
IMPORTANT: Blow out all foreign matter from the supply pipe before connecting to the gas
service cock.
15mm copper pipe to BS 2871 may be used for a simple supply not exceeding 3 metres
(10ft) from the gas meter. Where the installation contains many bends or the length is in
excess of 3 metres (l0ft), then the use of 22mm copper pipe is necessary.
1. Assemble the filter, ‘O’ ring and inlet tail to the gas inlet.
2. Depending on whether the main supply pipe is to be routed vertically or horizontally to
the appliance, connect the gas service cock (stamped ‘G) either directly to the gas inlet tail
or within the supply pipe. NOTE: The service cock should be as close to the appliance as
possible and the ON/OFF screw in an accessible position.
3. Ensure that the gas supply is turned OFF at the mains.
4. Connect to the gas supply.
5. Turn ON the gas supply and the gas service cock then test for gas soundness (BS
6891).
IMPORTANT: DO NOT TRY TO LIGHT THE APPLIANCE AT THIS STAGE. TO ALLOW
THE MAIN BURNER TO IGNITE WITHOUT THE OUTER CASE SECURED IN POSITION
IS
A
HAZARD
.
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Fig. 6
Page 5
INSTALLATION - Page 6
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Fig. 7
C. WATER CONNECTIONS
IMPORTANT: Flush out all foreign matterfrom the supply pipe before connecting to the
service cock.
1. Assemble the filter, olive and inlet tail to the water inlet. NOTE: The inlet tail need not be
used as a vertical supply can be routed directly onto the water inlet.
2. Depending on whether the main supply pipe is to be routed vertically or horizontally to
the appliance, connect the water service cock either directly to the water inlet tail or within
the supply pipe. NOTE: The service cock should be as close to the appliance as possible
and the ON/OFF screw in an accessible position.
3. Ensure that the mains water supply is turned OFF.
IMPORTANT: When routing the supply pipe to the appliance, ensure that it can be lowered
by approx 25mm to allow for disconnection when servicing.
4. Connect the hot water supply pipes to the water outlet - 15mm compression.
5. Turn ON the mains water supply, turn ON the water service cock and open all the hot
water
outlets to allow water to flow. Purge the air from the system by closing the hot water
outlets starting with the lowest level and ending with the outlet at the highest level.
6. Check for water leaks and remedy if found.
IMPORTANT
:
DO
NOT
TRY
TO
LIGHT
THE
APPLIANCE
AT
THIS
STAGE
.
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Fig. 8
D. LINT FILTER
This appliance has a lint filter fitted around the base of the pilot tube.
Ensure that the filter gauze is located inside both end caps and that the complete assembly
is correctly seated over the union nut at the base of the pilot tube.
Page 6
4. COMMISSIONING - Page 7
WARNING: The outer case of this appliance is not merely a cosmetic device. It is a
functioning component in the air supply to the burner and MUST BE replaced with great
care NOW, before any attempt is made to light the burners.
TO ALLOW THE MAIN BURNER TO IGNITE WITHOUT THE CASE IN POSITION IS A
HAZARD.
1. Refit the outer case ensuring it is correctly seated then secure (3 screws).
Fig
.
9
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2. Ensure that the gas and water supplies are turned ON.
3. Ensure that all hot water outlets are closed.
4. Remove the screw and sealing ring from the burner pressure test point and attach a
pressure gauge.
Fig. 10
5. Fully depress and hold the ON button ‘ ’and repeatedly press and release the IGN
button ‘ ’until the pilot is lit. The pilot flame can be observed through the pilot viewing
window
.
6. Hold the ON button ‘ ’in for a further 10 seconds after the pilot is lit, then release. If the
pilot goes out, repeat the lighting operation keeping the ON button ‘ ‘depressed a little
longer.
7. Test for gas soundness using a suitable leak detection fluid on all external gas joints.
8. Open a hot water outlet and the burner will ignite. Allow the water to run for a few
minutes then check the burner pressure - it should be 12.5 mbar (5 in w.g.), if the pressure
is
not
correct
see
the
FAULT
FINDING
section
.
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Fig. 11
Page 7
COMMISSIONING - Page 8
Fig. 12
NOTE: If a gas rate check is required, the gas consumption after 3 minutes running should
be approximately 48.5 l/mm (1.7³/min).
9. Turn OFF the hot water outlet and press the OFF button ’ ‘ on the appliance. Remove
the pressure gauge and replace the screw and sealing ring.
10. Relight the pilot. Turn ON a hot water outlet and check for gas soundness at the
pressure test point.
11
.
Turn
OFF
the
hot
water
outlet
.
Slide
the
bottom
cover
onto
the
appliance
.
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Fig. 13
Explain to the user how to operate the appliance. - see the "Instructions for Use" booklet.
Show the user the position of the Identification Badge.
HAND OVER THE "INSTRUCTIONS FOR USE" TO THE USER.
LEAVE THESE "INSTALLATION AND SERVICE" INSTRUCTIONS WITH THE USER
FOR USE ON FUTURE CALLS.
ADVISE
THE USER THAT FOR CONTINUED EFFICIENT AND SAFE OPERATION OF
THE APPLIANCE, IT IS IMPORTANT THAT SERVICING IS CARRIED OUT AT
INTERVALS RECOMMENDED BY THE LOCAL BRITISH GAS REGION OR C.O.R.G.I.
REGISTERED INSTALLER.
5. SERVICING - Page 8
To ensure continued efficient operation of the appliance, it is recommended that it is
checked and serviced as necessary at regular intervals. The frequency of servicing will
depend upon the particular installation conditions and usage, but in general once per year
should be adequate.
IMPORTANT: It is the law that any service work must be carried out by competent persons
such as British Gas or other c.o.r.g.i. registered personnel.
NOTE: In hard water areas, scale may build up on the push rod ,seals and on the
underside of the diaphragm housing. They may require regular descaling and regreasing.
Page 8
SERVICING - Page 9
Operate the appliance noting any faults in the component units. Carry out the servicing
procedure then correct any other faults by reference to ‘Replacement of Parts’, in which
section you will find details of how to dismantle and reassemble the following detailed
components
.
Check
that
the
burner
ignition
is
smooth
and
quiet
when
a
hot
tap
is
opened
.
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The burner ignition has been factory set and should not need adjustment. However, if
adjustment is required a slow ignition screw is fitted to the appliance and is situated above
the cap screw in the water governor body (fig. 6). The screw is factory set 2 full turns out
(anti-clockwise) from the fully in position. Turning the screw clockwise delays the ignition,
anti-clockwise advances the ignition.
WARNING: NEVER OPERATE THIS APPLIANCE WITH THE OUTER CASE REMOVED.
Fig. 14
1. Check the piezo unit, flame safety device and thermocouple, clean or replace if
necessary.
2. Remove the burner assembly and clean using a soft brush or vacuum cleaner.
3. Check the pilot injector and clean or replace if necessary. Also clean the lint filter.
4. Remove the water governor assembly complete with push rod. Replace the seals if
necessary. Descale and regrease the push rod, washers and diaphragm housing using
Dow Corning 111 silicone grease.
5. Check for water and gas soundness. Replace ‘O’ rings, sealing washers and gaskets
where
required.
Fig
.
15
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6. Clean any deposits off the heating unit by washing or brushing. Descale the heating unit
if required.
Fig. 16
Page 9
6. REPLACEMENT OF PARTS - Page 10
IMPORTANT: THE FOLLOWING WORK SHOULD ONLY BE CARRIED OUT BY A
COMPETENT SERVICE ENGINEER. E.G. BRITISH GAS OR CORGI REGISTERED
PERSONNEL
1. IF WATER IS DRAINED FROM THE SYSTEM DURING SERVICING, TURN ON ALL
HOT TAPS TO PURGE AIR FROM THE WATER SYSTEM. TURN THEM OFF IN
SEQUENCE, STARTING WITH THE TAP AT THE LOWEST LEVEL.
2. WHEN REPLACING ANY PARTS, RE-ASSEMBLE IN REVERSE ORDER UNLESS
OTHERWISE STATED.
This chart shows the steps to be taken in order access a specific part or perform a
particular function. Use this chart in conjunction with the detailed procedures on the
following
pages
.
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Page 10
REPLACEMENT OF PARTS - Page 11
6.1. PIEZO UNIT
It
will
NOT
be
necessary
to
remove
the
outer
case
.
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a. Slide out the bottom cover.
b. Disengage the electrode lead from the piezo unit.
c. Remove or loosen and pull aside the spark button retainer, taking care not to lose the
shakeproof washer.
d. Pull off the button and unscrew (anti-clockwise) the piezo from its housing
Fig. 17
6.2. GENERAL ACCESS/MAIN BURNER
a. Turn OFF the gas and water supplies at the service cocks.
b. Slide out the bottom cover.
c. Remove the 3 fixing screws and pull off the outer case.
Fig. 18
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d. Remove 4 fixing screws from the burner assembly (2 each side).
e. Remove 2 screws securing the front to the heating unit.
f. Pull the burner assembly slightly forwards to clear the injectors, then pull apart and
withdraw
taking care not to snag the pilot assembly.
NOTE: If required, the burner assembly can be dismantled and the burner bars replaced
individually. On re-assembly ensure that the burner inlets locate in the 14 holes.
NOTE: On re-assembly of the burner assembly take care not to snag the pilot assembly.
Ensure the front face of the assembly has located on the two studs on the heating unit.
Fig. 19
Page 11
REPLACEMENT OF PARTS - Page 12
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Fig. 20
6.3. THERMOCOUPLE AND SPARK ELECTRODE
a. Gain general access -see 6.2.
b. Remove the fixing screw and bracket then lower the spark electrode.
c. Disconnect the nut securing the thermocouple to the interrupter at the chassis base.
d. Disconnect the electrode lead from the back of the piezo unit, pull the lead up through
the grommet and remove.
e. On re-assembly, ensure that the pilot tube bends towards the rear of the appliance.(The
thermocouple will be vertical and nearest the burner manifold).
Fig. 21
6.4. PILOT INJECTOR
a. Gain general access -see 6.2.
b. Lift up the lint filter, disconnect the union nut and carefully lift up the pilot tube taking care
not to lose the pilot injector.
c. On re-assembly ensure the pilot injector is correctly seated (taper side down) and that
the lint filter is correctly assembled and located on the union nut.
NOTE: The lint filter can be cleaned if required.
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Fig. 22
6.5. FLAME SAFETY DEVICE
a. Gain general access -see 6.2.
b. Disengage the electrode lead from the piezo unit.
c. Release the thermocouple from the back of the flame safety device.
d. Release the union nuts above and below the flame safety device.
e. Release the union nut securing the pilot transfer tube to the flame safety device.
f. Remove the 3 screws securing the flame safety device to the chassis base and carefully
withdraw
the unit.
g. Re-assemble in reverse order.
Page 12
REPLACEMENT OF PARTS - Page 13
h. Test for gas soundness as follows:-
- Ensure the water service cock is in the OFF position. This will ensure water cannot flow
and open the automatic valve.
- Turn ON the gas, purge and light the pilot, this will pressurise the burner supply pipe.
- Test the gas supply to flame safety device and burner supply pipe above the flame safety
device for gas soundness using leak detection fluid.
i. Re-assemble remaining parts and ensure the water service cock is in the ON position.
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