Roca LAURA 20 User manual

Wall-Hung On-Demand Combination Waterheater
LAURA 20/20F

Laura wall-hung waterheaters
Table of Contents
Overall dimensions03
Pre-plumbing jig and Wall Spacing Frame04
Installation recommendations05
Start-up Checklist (I)06
Start-up Checklist (II)07
Pressures of gas08
Electronic PCB09
Electrical wiring Laura 2020 F10 Electrical wiring
Main components (I)
12
Main components (II)13
Control panel14
Stop and fault19
Hydraulic circuit
21
Mains Water Inlet22 Demand for Heating23
Mini-accumulator
24
Safety valve and By-Pass25
3-way valve26
Gauge and Lack-of-water pressure switch27
Central Heating mode operation28
Flame safeguard rectification system (I)31
Flame safeguard rectification system (II)32
Chimney “pull” safety 20/20
33 Process of code 2234
Combustion chamber36
Kit valve G20 and G2537
Cross-section of gas valve
Gas changeover Kit
38
Components of the boilers F and T
39
Flue duct kit (II)
41
Flue duct kit (V)
43
Flue duct kit (VII)
44
Central Heating programming (I)
45
Central Heating programming (II)
46
Central Heating programming (IV)
47
Central Heating programming (V)
48
Set-Up (I) - TECHNICIAN ONLY
49
55
56
Flue duct kit (III)
42
1
11
Sleeve15 Demand for Heating16 Demand for DHW (Winter)17
Flue duct kit (I)
40
Demand for DHW (Summer)18
DHW mode operation29 Overheat thermostat30
Burner
35
Set-Up (II) - TECHNICIAN ONLY
50
Mantenance
51
Fault codes
52
Outlines hydraulic (I)
53
Outlines hydraulic (II)
54
Table of contents01 Overall view02
Set Time
20
Central Heating programming (III)

Overall View
2
CE market.These waterheaters comply with the requirements of the Electromagnetic Compatibility Directive 89/336/EEC,
the Gas Appliance Directive 90/396/EEC,the Low Voltage Directive 73/23/EEC, and the Efficiency Directive 92/42/EEC .
Laura 20/20F
Low NOx emission level (Class 3) Laura 20/20F
Electrical protection level: IP44D
Laura 20/20Fwall-hung waterheaters
CERTIFIED FOR NORTH AMERICA
CSA
USA
CANADA

Overall Dimensions
3
17 23/32" 17 23/32"
33 1/2" 33 1/2"
15 7/16"
15 7/16"
Ø5"int. 9 3/4"
Laura 20/20F Laura 20/20F
Laura 20/20F wall-hung waterheaters
Ø127mm int.
247mm
450mm
392mm
850mm
850mm
392mm
450mm

Pre-Plumbing Jig and Wall Spacing Frame
4
Distance from the wall: 6 1/2"
Wall-mounting bracket, supplied
with the pre-plumbing jig
Gap between connections: 2 3/8"
PMI
Laura 20/20F wall-hung waterheaters
163 mm
60mm

Installation Recommendations
Observe current regulations and minimum distance from flammable materials
Please refer to the Instructions which are delivered with the appliance
5
Laura 20/20F wall-hung waterheaters
15 3/4" minimum
19/32" minimum
40cm
1.5cm

S tart-UpChecklist (l)
6
Connect power supply 220v 15 amp service
Connect room thermostat.
Unlock the pump motor shaft (turn center screw to bleed).
Make sure flue vent is properly installed.
Fill the primary loop (if no DHW storage tank has been installed) slowly until the pressure reaches 1-2 bar.
(If a DHW storage tank has been installed, then fill the secondary loop first).
Open the DHW circuit for it to fill up and vent.
With the gas inlet cock closed, start up the Central Heating/DHW mode (p15 #2). The boiler will per form a
lighting cycle and will then lock out under code 12.
Leave it like that for five minutes so that the pump , which is still running, can help vent the circuit.
Next chec k the pressure level (p14 #1) and top up if it has dropped below 1.5 bar.
Open the gas inlet cock, reset the system ( p14 #5) and the boiler will start operating.
Allow the boiler to operate in the Heating mode for ten minutes , in which period it should be checked that
all radiators warm up. Should one radiator fail to warm up, bleed the air out of it. But if it still does not warm up,
then the flow rates in all radiators should be balanced, alw ays optimizing the pump performance curve
(flow rate/pressure) through its speed selector control (to left of pump - select one of three settings).
Open the DHW tap with highest flow rate in the house. The boiler will operate for ten minutes
continuously at full output. If the flue spillage detection thermostat (p40) does not trip, that
means that the removal of flue gases is correct.
If a gas meter is available ,check the gas supply pressure (p8 & p37 gas supply pressure test point).
The DHW flow can be adjusted if necessary. To do that, open the tap fully and turn the main water inlet flow adjustment
screw (p22) until the leaving water temperature is 120ºF/49ºC (on screen, upper right), at full output.
Laura 20/20F wall-hung waterheaters

Start-Up Checklist (ll)
7
Connect tester to the operating gas pressure test point and check the working pressure with the boiler
operating at full output.
Remove the tester, replace the plug and washer, restart the system, and using soapy water check
the whole circuit for gas tightness.
For a higher level of comfort, particularly where substantial pressure variations in the water supply occur,
set the program close to the draw-off temperature.
Instruct the user on the following points:
Recommend user to read the User’s Instructions.
Instruct user on how to program the Central Heating and DHW temperature and the room
thermostat (if any).
Instruct user on how to top up the Heating system (1.5 mbar).
Demonstrate how the fault codes work for insufficient gas (12 and 17). This is the most common fault code
due to user error. Demonstrate to user how to reset after opening the gas inlet cock.
Recommend that user press reset button (p14 #5) whenever a red fault lamp lights up.
If the red light appears two or three consecutive times, tell the user to write down the fault codes and notify
the nearest Service Centeror Installer.
Train user on the various safety devices, recommendations and maintenance operations specified
in the waterheater instructions.
Laura 20/20F wall-hung waterheaters

Pressures of Gas
8
Gas Inlet Pressure:
G20(NG - Natural Gas): 8 water column inches (20 mbar)
G31(LP- Liquid Propane): 11.0 water column inches (27.4 mbar)
Gas supply pressure test point
(On the gas governor)
Operating gas
pressure test point
Gas input rates and pressures with Natural gas (G20) are for a
3
L.H.O.= 36,500Btu/m, density= 0,62, 59ºFand 14.7 PSI
(*) measured under standard conditions (59°Fand 14.7 PSI)
(**) burner setting pressure
2.38
2.26
1.96
1.64
0.87
83
71
55
38
14
1.06
1.04
0.89
0.77
0.38
341
332
241
179
52
Heat Output
79,347 Btu
71,412 Btu
59,510 Btu
47,608 Btu
27,771 Btu
3
Gas Input Rate (m/h) (*)
G20 G31
Pressure (mmwg) (**)
G20 G31
Laura 20/20F wall-hung waterheaters

9
Electronic PCB
Rear view of electronic PCB
CHIMNEY SWEEP
Sw10
CHIMNEY SWEEP
Sw10
T 160MA
3.15 A
2 A
TELEPHONE
REMOTE CONTROL
TELEPHONE
REMOTE CONTROL
WATER
PRESION
WATER
PRESION DHW DEMANDDHW DEMAND
C.T.
12/230
C.T.
12/230
SOLENOID VALVE AND BOILER MODELSOLENOID VALVE AND BOILER MODEL
IGNITION
TRANSFORMER
IGNITION
TRANSFORMER
SENSORS AND LIMIT STATSSENSORS AND LIMIT STATS
SAFETY RELAYSSAFETY RELAYS SAFETY FUSESAFETY FUSE
RELAYSRELAYS RELAYSRELAYS RELAYSRELAYS RELAYSRELAYS
EXHAUST FAN AND PUMPEXHAUST FAN AND PUMP
HOME AUTO.HOME AUTO.
C.T.FUSEC.T.FUSE
MAIN
FUSE
MAIN
FUSE
RÉSEAURÉSEAU
THERMOSTAT
COMMUNICATIONS
THERMOSTAT
COMMUNICATIONS
Laura 20/20F wall-hung waterheaters

White
Brown
Blue
10
Electrical Wiring
HEATING SENSOR
EXCHANGER SAFETY DEVICE
FLOW DETECTOR DEVICE
LACK-OF-WATER PRESSURE SWITCH
PUMP
POWER SOCKET 230v
ELECTRONIC BOX
DHW SENSOR
VARIABLE SIGNAL PRESSURE SWITCH
TWO SPEED FAN
TELEPHONE REMOTE
CONTROL CONNECTOR
Brown
Red
Grey
Orange
Blue
Orange
Orange
Grey
Blue
Blue
Green/yellow
Grey
Grey
Red
Red
Brown
Blue
Black
Blue
Black
Pump
Pump
Safety valve
Valves common
Bridge
Exchanger safety device
Heating sensor
Heating sensor
Sanitarium sensor
Sanitarium sensor
Exchanger safety device
Earth
Bridge
Heating Pressure switch
Heating Pressure switch
Fan 1 speed
Fan 2 speed
Common exhaust fan
Bridge
Pressure switch (Signal)
Pressure switch (Vcc)
Pressure switch (GND)
Flow meter mass
Flow meter signal
Flow meter supply
Bridge
Black
Red
Valve 18Th
Valve 12Th
Valve 7Th
SAFETY VALVE
27,769 Btu/7 Th
47,604 Btu/12 Th
71,406 Btu/18 Th
59,505 Btu/15 Th
79,340 Btru/20 Th
IGNITION ELECTRODES
AND IONISATION SENSOR
A.T.
BRIDGE
Laura 20/20F wall-hung waterheaters
GAS VALVE

11
Electrical Wiring
Natural draft open flue waterheater
Power socket
110V
Line volt
thermostat
Telephone
control via
Teletherm MT2
Lack-of-water
pressure switch
Flow detector device
Heating
sensor
Overheating
safety device
DHW sensor
Anti-backdraught
safety device
BLACK
BROWN
BLUE
Fan assisted waterheater
1ª Speed
Common
2ª Speed
Laura 20/20F wall-hung waterheaters

Main Components (I)
12
Compact casing
Top fixing: Locating pins
Bottom fixing: Screws
Removable decorative
Color of casing: White
RAL 9016
Stages of Output:
27,772 Btu
47,608 Btu
59,511 Btu
71,413 Btu
79,347 Btu
Adjustable for Heating
Net efficiency: 85%
Laura 20/20F wall-hung waterheaters

Draught Diverter
Ø flue socket collar: 127 Flue duct Ø 4.9" / 125 mm
Expansion Vessel
Fill pressure: 10.88 psi / 0.75 bar. Butyl diaphragm and nitrogen charge
Total/Useful capacity: 2.11 gal/1.19 gal (8 litres/4.5 litres)
Flue Spillage Limit Thermostat
Set at: 149º F / 65ºC
Heat Exchanger
Bithermal. 6 steps in DHW andHeating. Made of
copper and high-temperature aluminium paint.
Gas Valve
5 stages of output. Nat Gas governor: 6.8:8 wc" (17:25 mbar).
No internal diaphragms. Coil voltage: 12Vdc.
Combustion chamber
Compact. Side fixing rods
Ignition electrodes and
flame rod
Burner
Stainless steel. 13 “becks” “Clover-like” flame on the
ends for interlighting.
Mini-accumulator
Capacity: 1.6 qt/1.5 litres. Made of copper
Flow detector device
Circulator
Main Components (II)
13
Laura 20/20F wall-hung waterheaters

Control Panel
14
1. Pressure gauge
2. Heating+DHW service
3. DHW service
4. Stop
5. Fault Warning and Reset Button
6. Set Central Heating Temperature
7. Set DHW Temperature
8. Operating Temperature
Control Knob
9. Digital LCD Display
10. Set Time
11. ValidateProgram
12. Mode Selection: Manual/Program
13. Set Day
14. Set Day/Time/Programmer Knob
Air Purge
Circulator
Flow Meter
Control Panel for
Laura 20/20F
1
3
2
4
5
8
10
14
13
12
11
976
Laura 20/20F wall-hung waterheaters

Sleeve
15
1. Pressure gauge
2. Heating+DHW service
3. DHW service
4. Stop
5. Fault Warning and Reset Button
6. Set Central Heating Temperature
7. Set DHW Temperature
8. Operating Temperature Control Knob
9. Digital LCD Display
10. Set Time
11. Validate Program
12. Mode Selection: Manual/Program
13. Set Day
14. Set Day/Time/Programmer Knob
8354
1
2
6
7
9
1011
12
13 14
Laura 20/20F wall-hung waterheaters

Demand for Heating
16
1
2
3
4
5
6
7
(2) (1)
(3)
1. Press button for Central Heating + DHW service. The green indicator lamp
will light up.
2. Press the Set Central Heating Temperature button. The green lamp will light
up and the temperature digits on the display will flash.
3. Turn the temperature control knob as required. To exit the mode, press
any button or wait 10 seconds.
Winter Mode
Laura 20/20F wall-hung waterheaters

Demand for DHW
17
1. Press button for Central Heating + DHW service. The green indicator lamp
will light up.
2. Press the Set DHW Temperature button. The green lamp will light
up and the temperature digits on the display will flash.
3. Turn the temperature control knob as required. To exit the mode, press
any button or wait 10 seconds.
(1)
(2)
(3)
Winter Mode
Laura 20/20F wall-hung waterheaters

Demand for DHW
18
(2) (1)
(3)
Summer Mode
Laura 20/20F wall-hung waterheaters
1. Press button for DHW service. The green indicator lamp will light up.
2. Press the Set DHW Temperature button. The green lamp will light
up and the temperature digits on the display will flash.
3. Turn the temperature control knob as required. To exit the mode, press
any button or wait 10 seconds.

Stop and Fault
19
1. The fault code will be displayed on the screen. See list on last page.
2. The reset button will also light up. If necessary, press it once the fault has cleared.
1. Press the Stop button. The boiler will switch to permanent monitoring mode.
(1)
(2)
(1)
Laura 20/20F wall-hung waterheaters