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Related Manuals for Myson Midas Sfi
Summary of Contents for Myson Midas Sfi
- Page 1 Midas Sfi wall mounted combination gas boiler G.C. Appliance No. Midas Sfi 47 494 04 IMPORTANT FOR USE WITH NATURAL GAS ONLY. Read these instructions thoroughly before working on the boiler. Leave these instructions adjacent to the gas meter.
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Page 2: Table Of Contents
LIST OF CONTENTS Page Section Subject Introduction Method of operation General requirements Delivery Electricity supply Gas supply Air supply Flue system Technical data Boiler location Water system Important installation notes Sealed system requirements Optional open system Installation procedure Commissioning Balancing the system Final assembly and handing over installation Annual servicing Replacement of parts... -
Page 3: Introduction
6. GASSUPPLY The Midas Sfi requires 3.4 mYh (120 ftVh) of natural gas (the input after 10 minutes use at maximum). The meter and supply pipes must be capable of delivering this quantity of gas in addition to the demand from any other appliances in the house. -
Page 4: Air Supply
Maximum central heating input 3 6 . 6 Minimum central heating input (m-on) 13.2 Maximum central heatina output 29.3 Minimum central heating output (modulation) Maximum hot water input 3 6 . 6 Maximum hot water output 2 9 . 3 Maximum burner pressure 1 6 . -
Page 5: Boiler Location
Gas Installation in Timber Framed Housing” reference DM2. If in doubt advice must be sought from the local region of British Gas or from Myson Heating. The boiler may be installed in any room, although particular attention is drawn to the requirements of the latest IEE Wiring Regulations and, in Scotland, the electrical provisions of the building regulations applicable in Scotland, with respect to the installation of the boiler in a room containing a bath or shower. -
Page 6: Water System
The maximum working pressure of the Midas Sfi is 10 bar (145 Ibfhn2). If the mains water pressure is likely to exceed this, a pressure reducing valve must be fitted to the cold water inlet. -
Page 7: Sealed System Requirements
OPEN THE MAIN BOILER PACK CHECK THE OUTER PANELS PACK The Midas Sfi is received in two packs. unpack the larger of The outer panel pack contains the outer front and side the two. Remove the outer panels pack and place to one panels together with the facia cover and bottom panel. -
Page 8: Prepare The Boiler
use Frames 5 to 12. For Side Exit Flue use Frames 13 to 18. REAR EXIT FLUE PREPARE THE BOILER All dimensions in mm 1 . Remove inner case front (4 screws). 2. Disconnect the %way plug from the air flow Sensor and the 3. - Page 9 RE-ASSEMBLE THE BOILER FIT THE FLUWERMINAL tube and in front of the swaged section. 4. Secure the flue/terminal assembly to the boiler using the two halves of the clamping ring as shown below. Ensure that the of the air tube. PREPARE AND FIT THE BOILER 1.
- Page 10 FIT THE FLUE/TERMINAL FLUE EXTENSION The flue extension kit allows ASSEMBLY the standard flue/terminal assembly to be extended by 965 1. Remove the 4 screws, sealing plate and gasket from the side A maximum of two flue extensions may be used, if required. through which the flue is to exit and use to seal the rear exit.
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Page 11: Commissioning
CONNECT THE WATER SUPPLY CONNECT THE POWER SUPPLY CABLE Refer also to page section 5. 1. Make connections as shown below. For dimensions see page 5, 1. Remove the electrics cover (4 screws) and remove the facia panel section 12. (4 screws) and carefully pull forward (see frame 42). -
Page 12: Balancing The System
PURGE THE SUPPLY AND CHECK THE PILOT FLAME Purge the gas supply 2. Turn on the gas supply and open the boiler service cock to purge in accordance with BS6891 (the cock is open when the operating slot is vertical). Retighten test point screw and test for gas soundness. Check the pilot flame insulation panel (4 screws). -
Page 13: Final Assembly And Handing Over Installation
19. FINAL ASSEMBLY AND HANDING OVER THE INSTALLATION 2. Set the timer to the correct time (do not rotate the dial anticlockwise). Hand the User Instructions to the User and instruct in the safe operation of the boiler and controls. Advise the User of the precautions necessary to prevent damage to the system and to the building in the event of the system remaining inoperative during frost conditions. -
Page 14: Replacement Of Parts
REPLACEMENT OF PARTS The procedure for the replacement of parts is given in frames 29 to 61. WARNING: Before commencing work: Set the programme selector switch to ‘CH off‘, ‘HW off‘! Allow the boiler to cool and isolate the electricity supply. Turn off the gas supply at the gas service cock. -
Page 15: Gas Valve
TO REPLACE THE COMBUSTION TO REPLACE THE MAIN HEAT CHAMBER INSULATION PANELS EXCHANGER 1. Remove combustion chamber as described in frame 33, steps 1 26, steps 4 to and 3. 2. Slide out the two side panels. 2. Close the system isolation valves. Drain the boiler down using the safety valve. - Page 16 Frames 38 on do not require removil of the m m seal compartment front cover TO REPLACE THE GAS VALVE TO REPLACE MAIN GAS VALVE OPERATING SOLENOID Refer to illustration, frame 38. 1. Ensure that the gas supply is off and electricity supply is Refer to illustration,.frame 38.
- Page 17 TO REPLACE THE PRESSURE TO REPLACE THE IGNITION GAUGE CONTROL BOARD Close off the system isolation valves. Remove bottom case panel Detach the facia panel (4 screws), carefully pulling it forward, and (see frame 2), drain the primary circuit by opening the safety remove the electrics cover (4 screws).
- Page 18 TO REPLACE THE CENTRAL HEATING FLOW SENSOR 1. Close off the system isolation valves, remove bottom case panel (see frame 2), and drain boiler down using the safety valve. 2. Pull off terminals from the sensor. 3. Remove sensor. Reassemble in reverse order with new sensor. 5.
- Page 19 TO REPLACE OR CLEAN TO REPLACE OR DESCALE THE REGULATOR AND FILTER SECONDARY HEAT EXCHANGER Close mains water inlet isolation valve. Drain by opening the lowest 1. Close the isolation valves. hot water taps and the drain point in the mains isolation valve. 2.
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Page 20: Wiring Diagrams
COLOUR CODE blue P - purple violet brown r- red green while yellow orange yellow CABLE BLOCK CLAMP WHEN FITTING A ROOM THERMOSTAT 1. Remare link betwean R CENTRAL HEATING and R (FLOW) SENSOR 2. Connect Room Thermostat between R and R I I l l IGNITION... - Page 21 COLOUR CODE blue purple PURGE ROOM THERMOSTAT black violet SWITCH IF FITTED brown green white yellow orange green and pk- pink yellow Mains 240V TRANSFORMER C 0 N T P.C.B. CH SWITCH HOT WATER PUMP CENTRAL HEATING CENTRAL TEMPERATURE HEATING CONTROL PUMP HOT WATER...
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Page 22: Fault Finding Guides
23. FAULT FINDING Section 1 : Appliance operating procedure. To assist fault finding six light emitting diodes (LEDs) have been incorporated on the main control board to indicate certain functions of the board. By using these LEDs it should be possible to identify where the problem lies and to rectify. LED 1 Will remain on until the fan has produced enough air for complete combustion at low rate low rate air detector. - Page 23 OFF 0 0 0 0 0 0 Hot water pump on overrun. Fan on overrun. Fan slowing down to low fan. 0 0 0 0 0 0 Fan speed below high rate. Hot water pump on overrun. 0 0 0 0 0 0 Pump overrun finished. Fan on low overrun. 0 Fan overrun finished.
- Page 24 Section 2: Fault finding flow charts Preliminary elegtrical system checks i.e. Earth Continuity, Short Circuit, Polarity and Resistance to Earth are the first electrical checks to be carried out during a fault finding procedure. On completion of the service/fault finding task which has required the breaking and remaking of electrical connections, then the checks Earth Continuity, Short Circuit, Polarity and Resistance to Earth must be repeated.
- Page 25 Continued from Y E S ode lead Change ion. spark on gas valve, If pilot on gas valve until the Disconnect electricity remains small, flameenvelops the supply. disconnect air changeorcleanthe electrode and Changeair extends 10 mm past it flow sensor. bewteen A1-A2 and resent? has cooled.
- Page 26 sensor. is closed circuit. lote: When first switching on the electricity supply, the secondary heat exchanger within the appliance will be cold. Therefore will bring on the gas at full rate for a few seconds before reverting to the reheat or top-up mode (low gas rate and fan speed) until the secondary heat exchanger is up temperature.
- Page 27 Continued from Inform the customer initially 16mbar? boiler satisfactorily. is working Set gasvalve-see frame 25. sensor. initially 16mbar' inlet hot water inlet sensor andcheckthat it rotates freely. assembly. circuit? assembly. DC at the modulating Change main control board. tube blocked? tube blocked? sensing Change main control...
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Page 28: Exploded Views
24. EXPLODED VIEWS a. Panels and chassis... - Page 29 Internal parts and pipework Page...
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Page 30: Short List Spare Parts
Key No. Description Part No. Part Facia m e r assembly Front panel Side panel left hand 324 002 Side panel right hand 324 003 Inspection window assembly 324 008 Burner assembly Burner Furigas 175-500-024 (silver) Alternative to key 20A 382 950 Burner Bray AB24016M (blue) Alternative to key... - Page 31 Page...
- Page 32 WIRING CONNECTIONS TO A ROOM THERMOSTAT Room thermostat model " Midas Sfi boiler Room terminal block thermostat connections terminals follows: other models room thermostat connect as Room thermostat R I N Midas Sfi boiler terminal block Accelerator connections heater Telephone: 091 482 6699. Telex:...
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