Heatrae Sadia MegaFlo Installation Manual Download Page 28

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8.5 DESCALING IMMERSION HEATER(S)

Open the cover(s) to the immersion heater housing(s) and disconnect wiring from immersion 

heater(s). Remove the thermostat by carefully pulling outwards from the immersion heater. Un

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screw immersion heater backnut(s) and remove immersion heater from the unit. A key spanner is 

supplied with the Megaflo unit for easy removal/tightening of the immersion heater(s). Over time 

the immersion heater gasket may become stuck to the mating surface. To break the seal insert 

a round bladed screwdriver into one of the pockets on the immersion heater and gently lever up 

and down. 

Carefully remove any scale from the surface of the element(s). DO NOT use a sharp implement 

as damage to the element surface could be caused. Ensure sealing surfaces are clean and seals 

are undamaged, if in doubt fit a new gasket. 

Replace immersion heater(s) ensuring the lower (right angled) element hangs vertically downwards 

towards the base of the unit. It may be helpful to support the immersion heater using a round bladed 

screwdriver inserted into one of the thermostat pockets whilst the backnut is tightened. Replace 

the thermostat(s) by carefully plugging the two male spade terminations on the underside of the 

thermostat head into the corresponding terminations on the element. 
Rewire the  immersion heater(s) in accordance with  Figure  9. Close and secure terminal 

cover(s).

8.6 REFILLING SYSTEM

DO NOT switch on the immersion heater(s) or boiler until the system has been completely 

refilled.
Close the drain tap. With the hot tap open, turn on mains water supply. When water flows from 

the hot tap allow to flow for a short while to purge air and to flush through any disturbed par

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ticles. Close hot tap and then open successive hot taps in system to purge any air. The electrical 

supply can now be switched on.

8.7 BENCHMARK

TM

 LOG BOOK

Maintenance

Summary of Contents for MegaFlo

Page 1: ...Megaflo HE 1 36005823 issue 6...

Page 2: ...5 INSTALLATION INDIRECT UNITS 18 6 COMMISSIONING 23 7 USER INSTRUCTIONS 25 8 MAINTENANCE 27 9 FAULT FINDING SERVICING 29 10 DIMENSIONS SPECIFICATIONS 32 11 GUARANTEE 35 12 CONTACTS 36 Contents Please...

Page 3: ...pes It is supplied complete with all its necessary inlet and safety controls electric immersion heater s and for indirect units a cylinder thermostat thermal cut out 2 port motor ised valve and wiring...

Page 4: ...the components for your Megaflo unit are con tained in the package The following components are supplied as standard with your Megaflo unit Factory fitted immersion heater s and thermal controls Cold...

Page 5: ...n supply pipe should be in 22mm The minimum mains water supply requirements should be 0 15 MPa 1 5 bar working pressure and 20 litres per min ute flowrate At these values outlet flowrates may be poor...

Page 6: ...Type AA AB AD or AG air gap be employed Water supplies that have either inadequate pressure or where the supply may be intermittent Situations where it is not possible to safely pipe away any discharg...

Page 7: ...nnection and a single Check Valve The valve can be fitted in any orienta tion to suit the installation however ensure that the Valve is installed with the direction of flow arrows stamped on the side...

Page 8: ...alve can be correctly installed ISOLATING VALVE MAINS IN 22MM COMPRESSION CONNECTION PRESSURE REDUCING VALVE HOUSING PRESSURE REDUCING VALVE CARTRIDGE 3 BAR 22MM COMPRESSION CONNECTION OUTLET TO MEGAF...

Page 9: ...Pressure Relief Valve Balanced cold water draw off to shower mixer valves Note tapping must be min 3m from Megaflo inlet connection Balanced HWS and MCWS to each shower Isolating Regulating Valves as...

Page 10: ...Drain Off Cock Temperature Pressure Relief Valve Balanced cold water draw off Balanced HWS and MCWS to bathrooms showers cloakrooms etc Isolating Regulating Valves as required HWS supply Expansion Cor...

Page 11: ...upplied available as an ac cessory order code no 95 970 509 The secondary return pipe should be in 15mm pipe and incorporate a check valve to prevent backflow A suitable WRAS approved bronze circulati...

Page 12: ...ol or safety valves should be tampered with iv Water may drip from the discharge pipe of the pressure relief device Expansion Valve and this pipe must be left open to atmosphere The discharge pipe sho...

Page 13: ...ECTION 3 9 The discharge pipe D1 from the vessel up to and including the tundish is generally sup plied by the manufacturer of the hot water storage system Where otherwise the installation should incl...

Page 14: ...single common discharge pipe should be at least one pipe size larger than the largest individual discharge pipe D2 to be connected If unvented hot water storage systems are installed where discharges...

Page 15: ...35mm UP TO 9M UP TO 18M UP TO 27M 0 8M 1 0M 1 4M G 3 4 22MM 28mm 35mm 42mm UP TO 9M UP TO 18M UP TO 27M 1 0M 1 4M 1 7M G 1 28MM 35mm 42mm 54mm UP TO 9M UP TO 18M UP TO 27M 1 4M 1 7M 2 3M Fixed grating...

Page 16: ...helpful to support the immersion heater using a round bladed screwdriver inserted into one of the thermostat pockets Hand tighten the brass backnut Secure the immersion heater in position by tighteni...

Page 17: ...OUT S IN ANY CIRCUMSTANCES DISCONNECT FROM THE MAINS SUPPLY BEFORE REMOVING ANY COVERS NEVER ATTEMPT TO REPLACE AN IMMERSION HEATER OTHER THAN WITH THE REC OMMENDED HEATRAE SADIA MEGAFLO SPARE PART Fi...

Page 18: ...ing should be carried out by a competent electrician and be in accordance with the latest I E E Wiring Regulations The Megaflo Indirect Thermostat and Thermal Cut Out are factory pre wired The 2 port...

Page 19: ...ug Ensure the cylinder is drained of water first Open the cover to the upper immersion heater boss Unscrew the brass backnut using the key spanner provided with the unit Remove the blanking plate and...

Page 20: ...TAT THERMOSTAT ADJUSTMENT INDIRECT THERMAL CUT OUT INDIRECT THERMAL CUT OUT RESET BUTTON NOTE THE HOUSING COVER AND ELEMENT ASSEMBLY HAVE BEEN REMOVED FROM THIS VIEW FOR CLARITY Figure 12 Indirect con...

Page 21: ...LINKED BACK TO THE MAINS EARTH SUPPLY 3 USE COPPER LINKS SUPPLIED TO MAKE CONNECTIONS BETWEEN TERMINALS 4 DO NOT MOUNT WIRING CENTRE ON CYLINDER 5 THE ABOVE DIAGRAM IS FOR GUIDANCE ONLY HEATRAE SADIA...

Page 22: ...LY 3 ASSUMES BASIC BOILER WITH EXTERNAL PUMP 4 USE COPPER LINKS SUPPLIED TO MAKE CONNECTIONS BETWEEN TERMINALS 5 DO NOT MOUNT WIRING CENTRE ON CYLINDER 6 THE ABOVE DIAGRAM IS FOR GUIDANCE ONLY HEATRAE...

Page 23: ...y through the tundish and discharge pipework Close valve ensure water flow stops and valve reseats correctly ii Repeat for the Expansion Valve situated on the Cold Water Combination Valve or Expansion...

Page 24: ...Expansion Valve or Temperature and Pres sure Relief Valve during the heating cycle 6 5 BENCHMARKTM LOG BOOK On completion of the installation and commissioning procedures detailed in this manual the...

Page 25: ...y doubt consult a competent electrician INDIRECT UNITS Indirect units CL models are fitted with an Indirect Thermostat which controls a 2 port motorised valve and hence the temperature of the water in...

Page 26: ...e cylinder via programmers immersion isolation switch es ii Turn off the water supply to the Megaflo unit by turning off the isolating valve on the Cold Water Combination Valve Turn the black handle s...

Page 27: ...STRAINER The strainer is incorporated within the Pressure Reducing Valve housing of the Cold Water Combination Valve see Figure 2 To inspect and clean the strainer i Turn off the isolating valve on th...

Page 28: ...gasket Replace immersion heater s ensuring the lower right angled element hangs vertically downwards towards the base of the unit It may be helpful to support the immersion heater using a round bladed...

Page 29: ...on heater gasket 95 611 822 Immersion heater backnut 95 607 869 Immersion heater key 95 607 861 Immersion heater blanking plug 95 605 881 Tundish 95 605 838 Expansion relief valve cartridge 8bar 95 60...

Page 30: ...bt contact the Heatrae Sadia Service Department see Section 12 Figure 15 Exploded view of the Cold Water Combination Valve and Expansion Core Unit Valve Body 95 605 029 Check Valve Housing 95 605 028...

Page 31: ...ostat 6 INDIRECT motorised valve not connected correctly 6 Check wiring and or plumbing connections to motorised valve see Diagram 9 Water discharges 1 INTERMITTENTLY from Expansion Relief Valve Expan...

Page 32: ...32 32 10 Dimensions Specifications Dimensions Specifications Figure 16 Dimensions Temperature Pressure Relief Valve Temperature Pressure Relief Valve Direct units Indirect units...

Page 33: ...imensions Table 4 Direct units Technical specifications Table 5 Indirect units Technical specifications NOTE Coil heating performance based on a primary flow rate of 15 l min at 80o C Temperature rise...

Page 34: ...on CFC HCFC free fire retardant expanded polyurethane foam with zero ozone depletion potential It has a Global Warming Potential GWP of 3 1 Nominal thickness 50mm Pipe connections All connections acce...

Page 35: ...e water v It has not been installed in a location liable to be subjected to frost nor has it been tampered with or been subjected to misuse or neglect vi No factory fitted parts have been removed for...

Page 36: ...l 0845 0553811 E mail sales ewh co uk SPD Special Product Division Units 9 10 Hexagon Business Centre Springfield Road Hayes Middlesex UB40 0TY Tel 020 8606 3567 Parts Center Network 65 Business Park...

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