Maintenance; General; Standard Inspection & Maintenance Operations - Heatrae Sadia Megaflo Eco SystemFit 145sf Instructions Manual

9. Maintenance

9.1 General

Maintenance requirements
Unvented hot water systems have a continuing
maintenance requirement in order to ensure safe
working and optimum performance. It is essential that
the relief valve(s) are periodically inspected and manually
opened to ensure no blockage has occurred in the valves
or discharge pipework. Maintenance of this appliance
should only be carried out by a suitably qualified person.
Failure to do so could invalidate the warranty.
Similarly cleaning of the strainer element and replacement
of the air in the product will help to prevent possible
operational faults.
The maintenance checks described below should be
performed by a competent person on a regular basis, e.g.
annually to coincide with boiler maintenance.
After any maintenance, please complete the relevant
Service Interval Record section of the Benchmark
Checklist on page 30 of this document.
9.2 Standard inspection & maintenance
operation
Inspection
The immersion heater boss can be used as an access for
inspecting the cylinder internally.
Safety valve operation
CAUTION
Water discharged may be very hot!
`
Manually operate the temperature/pressure relief
valve 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.
` Repeat the above procedure for the expansion relief
valve.
Strainer
` Turn off the isolating valve prior to the Pressure
Reducing Valve or the main stop cock to the system.
` Open the lowest hot tap in the system to relieve the
system pressure.
` Using a spanner unscrew the pressure reducing
cartridge and remove the moulded housing. The
strainer will be removed with the cartridge.
` Wash any particulate matter from the strainer under
clean running water.
` Replace the strainer and screw the Pressure Reducing
Valve cartridge into the moulded housing.
` Close hot tap, turn on isolating valve or main stop
cock to the system. Check for leaks.
Descaling immersion heater(s)
` Turn off the mains water supply, isolate the electrical
supply and turn off boiler
` Attach a hosepipe to the drain cock having sufficient
length to take water to a suitable discharge point
below the level of the unit.
`
Open a hot tap close to the unit and open drain
cock to drain unit. If water fails to drain vent the unit
manually by opening the temperature and pressure
relief valve.
` Open the cover(s) to the immersion heater housing(s)
and disconnect wiring from immersion heater(s)
thermostat(s).
` Unscrew the immersion heater backnut(s) and
withdraw the immersion heater from the cylinder. A key
spanner is supplied with the product for easy removal
and 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. Take care when
lifting the immersion heater out of the cylinder and
work within safe working practices.
` Carefully remove any scale from the surface of the
element(s).
CAUTION
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. (spare part
number 70 351 65 )
` Replace immersion heater(s), making sure not to trap
the gasket.
` Rewire, check, close and secure immersion heater
housing cover(s).
Re-commissioning
` Check all electrical and plumbing connections are
secure. Close the drain cock.
` With a hot tap open, turn on the cold water supply
and allow unit to refill.
`
DO NOT switch on the immersion heater(s) or boiler
until the unit is full.
` When water flows from the hot tap allow to flow
for a short while to purge air and flush through any
disturbed particles.
` Close hot tap and then open successive hot taps in
system to purge any air.
` When completely full and purged check system for
leaks.
`
The heating source (immersion heater(s) or boiler)
can then be switched on.
25