Heatrae Sadia Megaflo Eco Solar Series Product Manual page 28

Maintenance
Maintenance requirements
To ensure the continued optimum performance of the MEGAFLO Eco Solar it should be regularly maintained. This is of particular importance
in hard water areas or where the water supply contains particulate matter. Maintenance should be carried out by a competent person and any
replacement parts used should be authorised MEGAFLO Eco Solar spare parts. It is recommended that maintenance is carried out every 12
months and includes the checks detailed below.
In hard water areas consideration should be given to periodically descaling the immersion heater elements. To do this the MEGAFLO Eco Solar unit
will need to be drained, details below list how to drain the unit and remove the immersion heater(s).
Check operation of Safety Valves
Slowly open the Temperature and Pressure Relief Valve by twisting its cap for a few seconds. Check water is discharged and that it flows freely
through the tundish and discharge pipework. Check valve reseats correctly when released.
NOTE: The water discharged may be very hot.
Repeat the procedure for the 8 Bar Pressure Relief Valve.
Clean the strainer
The strainer is incorporated within the Pressure Reducing Valve housing of the Cold Water Combination Valve (see Figure 17, p. 31). To inspect
and clean the strainer:
i) Turn off the isolating valve on the 3 Bar Pressure Reducing Valve by turning the blue handle (if fitted in this position) so it lies 90º to the direction
of flow or main stop cock to the house.
ii) Open the lowest hot tap in the system to relieve the system pressure.
iii) Using a spanner unscrew the Pressure Reducing Cartridge and remove the moulded housing. The strainer will be removed with the cartridge.
iv) Wash any particulate matter from the strainer under clean running water.
v) Replace the strainer and screw the Pressure Reducing Valve Cartridge into the moulded housing.
vi) Close hot tap, turn on isolating valve by turning handle so it lies parallel to the direction of flow. Check for leaks.
Draining the MEGAFLO Eco Solar unit
Switch off the electrical supply to the immersion heater(s) and shut down the boiler on indirect units. Turn off the mains water supply
to the MEGAFLO Eco Solar unit. Attach a hosepipe to the drain cock having sufficient length to take water to a suitable discharge point below the
level of the unit, at least one metre below the unit is recommended. Open hot water tap nearest to the MEGAFLO Eco Solar to relieve the system
pressure. Open drain cock. If water fails to drain from the MEGAFLO Eco Solar vent the unit by manually opening the Temperature / Pressure Relief
Valve.
Descaling immersion heater(s)
Open the cover(s) to the immersion heater housing(s) and disconnect wiring from immersion heater(s). Remove the thermostat capillaries, 2 or
4 depending on which unit being serviced. Unscrew immersion heater backnut(s) and remove immersion heater from the unit. A key spanner is
supplied with the MEGAFLO Eco Solar 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 shafted 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 shafted 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 into the corresponding terminations on the element.
Rewire the immersion heater(s) in accordance with Figure12, p. 20 or Figure 15, p. 23. Close and secure terminal cover(s).
Expansion Vessel Charge Pressure
Remove the dust cap from the top of the expansion vessel. Check the charge pressure using a tyre pressure gauge. The charge pressure (with the
system depressurised) should be 0.3MPa (3 Bar). If it is lower than the required setting it should be re-charged using a tyre pump (schrader valve
type). DO NOT OVER CHARGE. Re-check the pressure and when correct replace the dust cap.
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 particles. Close hot tap and then open successive hot taps in system to purge any air. The electrical
supply can now be switched on.
Benchmark TM
On completion of any maintenance or service of the MEGAFLO Eco Solar, the Benchmark TM "Installation, Commissioning and Service Record"
should be filled in to record the actions taken and the date the work was undertaken. (Section 3, page 34 & 35)
Unvented Hot Water Cylinder
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