system. If during the hot water cycle the flow to the c/h system goes up in temperature,
this indicates that the three-way valve has an internal leak and needs to be cleaned. The
boiler needs to be drained and the three-way valve can be dismounted. Remove the
ignition cable and then disconnect the fan. Take off the burner by removing 6 x M6 nuts.
Check the inside of the heat exchanger, look for any irregularities. When the main heat
exchanger has dirt on the inside of the elements, clean with a hard brush (no steel), or
with lemon acid. Afterwards use a vacuum cleaner to remove all the dirt.
The burner
itself should never be cleaned.
When the condensate water out of the cleaning tube of the syphon is dirty, the syphon
requires cleaning.
Rinse the syphon through the syphon flush connection or with the burner dismounted
flush cold water through the syphon heat exchanger connection or with access to the
flue, flush the heat exchanger and syphon through by pouring water down the 70mm
inner flue duct.
After flushing ensure that the condense syphon is refilled with water, otherwise flue
products may be passed through the condensate pipe-work into the building.
Take off the plastic mixing box at the inlet side of the fan, inspect the fan impeller for
damage. When the impeller of the fan is dirty every blade has to be carefully cleaned
until the original plastic material is clearly visible.
When dirt is left on the blades the fan will run out of balance and, due to the fast fan
speeds (>6000 rpm), additional and unnecessary loads will be placed on the fan
bearings significantly reducing the lifetime of the component.
Check the distance of the electrode to the burner; this should be a 3mm ~ 4mm gap.
Bend the electrode, without touching the burner surface, very carefully until a space of
3mm ~ 4mm is achieved.
Check the seals on the gas connections and ensure that the gas service is sound by
completing a gas soundness test.
Check the wiring and fuse at the spur is no greater than 3amp.
35.3 Service records
Complete the appliance service record, ask the user to sign it and hand them the second
copy. Return the top copy to Mikrofill and service company or service engineer to retain
copy on file for their/your records.
Complete an appliance service label and attach to underside of appliance case.
36. Decommissioning the boiler
When decommissioning the boiler, precautions should be taken to avoid frost damage.
Therefore it is essential that both the boiler and the central heating system are
completely drained down.
To do this remove the front casing and connect a hose to the central heating drain point.
The system should be vented by opening the DHW valve and /or the manual air vent on
the central heating circuit.
