Glow-worm Ultracom 2 24cxi Installation And Servicing page 51

19.4.1 Pump (head only)
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Disconnect the electrical plug (26) from the main board.
• Disconnect the electrical plug (25) from the pump head.
• Remove the four cap head screws (27).
• Carefully remove the pump head (28) together with cable.
Do not strain cable.
• Reconnect wiring to new pump head and fit cover.
• Fit the new pump head by repeating the operations in
reverse.
19.4.2 Safety discharge valve
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Undo the safety discharge valve union and remove from the
pipework (7).
• Remove the securing clip (6) and withdraw the safety
discharge valve (8).
• Fit new 'O' ring. Refill, vent and pressurise the boiler.
19.4.3 Automatic air vent
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Remove the retaining clip (29).
• Remove the automatic air vent (20).
• Fit the new automatic air vent and 'O' ring ensuring the vent
cap is left loose.
• Refill, vent and pressurise the boiler.
Low water pressure sensor
19.4.4
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Disconnect the electrical lead (15).
• Remove the retaining clip (17), remove the low water
pressure sensor (16).
• Fit the new low water pressure sensor.
• Refill vent and pressurise the boiler.
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Flow sensor
19.4.5
• Drain the boiler hot water circuit as described in the
appropriate chapter "Draining".
• Remove the side securing clip and the electrical connection (4).
• Disengage the flow sensor (5).
• After replacing the flow sensor, open the cold-water isolation
valve and slowly open a hot water tap to remove air.
19.4.6 bypass
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Remove the retaining clip (23) to remove the bypass screw (24).
• After replacing the bypass, refill, vent and pressurise the
boiler.
Three way valve
19.4.7
• Drain the boiler heating circuit as described in the
appropriate chapter "Draining".
• Disconnect the electrical plug (1).
• Remove the two retaining screws (2).
• Remove the three way valve (3).
• Fit new three way valve assembly.
• Refill, vent and pressurise the boiler.
19.4.8 Plate-to-plate heat exchanger
• Drain the boiler heating and domestic hot water circuits as
described in the appropriate chapter "Draining".
• Remove the two securing screws (10).
• Open the two retaining brackets (9).
• Remove the plate-to-plate heat exchanger (14) by lifting it up.
• When replacing the plate-to-plate heat exchanger, ensure
that the four rubber sealing washers are fitted into the
hydroblock.
NOTE: The plate-to-plate heat exchanger only fits one way.
• Refill, vent and pressurise the boiler.
MAINTENANCE
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