Halstead Ace High, Installation And Servicing Instructions, Page: 32 / 40

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9.14
DHW FLOW SWITCH BODY
9.15 PUMP
9.16 PRESSURE RELIEF VALVE
9.18
AUTO AIR VENT
9.17
PRESSURE GAUGE
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Turn the CH flow and return valves to the closed position to
isolate the boiler (see section 5.1), then drain the appliance.
c) Remove the screw securing the electrical connections cover on
the pump, and remove the electrical connections.
d) Either unscrew the two pump unions and remove the entire
pump (using new sealing gaskets) OR unscrew the four socket
head cap screws and remove the pump head only.
e) Replace the pump (or pump head), re-assemble in reverse
order, and re-commission the system as explained in section
5.1.
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Turn the CH flow and return valves to the closed position to
isolate the boiler (see section 5.1), then drain the appliance.
c) Unscrew the union connections to the pressure relief valve,
and remove the valve.
d) Replace the valve, re-assemble in reverse order, and re-
commission the system as explained in section 5.1.
a) Remove the casing front panel and sealed chamber front
panel as described in section 9.1 steps (a) and (b).
b) Remove the combustion chamber front panel and burner
locating bracket (7 screws). Take care not to damage the
insulation.
c) Turn the CH flow and return valves to the closed position to
isolate the boiler (see section 5.1), then drain the appliance.
d) Remove the plastic pipe from the top of the air vent, and
unscrew the auto air vent using a suitable pipe wrench.
e) Fit replacement and re-assemble in reverse order.
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Turn the CH flow and return valves to the closed position to
isolate the boiler (see section 5.1), then drain the appliance.
c) Unscrew the pressure gauge connection from the valve
assembly, unclip the pressure gauge head out of the fascia
panel, and remove the pressure gauge.
d) Replace the pressure gauge, re-assemble in reverse order, and
re-commission the system as explained in section 5.1.
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Remove the complete controls fascia panel and base plate as
described in section 9.13.
c) Isolate the cold water inlet valve and drain the DHW circuit by
opening all DHW taps.
d) Refer to Figure 38. Unscrew the two screws securing the
switch body to the main brass block. Note the position of the
alignment pin.
e) Remove the two spring clips, which secure the pressure
sensing pipes into the switch body and pull out the pipes,
taking care to collect any residual water.
f) Remove the switch body by sliding to the right.
g) Replace the flow switch and re-assemble in reverse order.
Ensure that the alignment pin is correctly aligned.
Re-commission the hot water system as explained in section
5.1.
9.13
DHW HEAT EXCHANGER
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Turn the CH flow and return valves to the closed position to
isolate the boiler (see section 5.1), then drain the appliance.
c) Unscrew the pressure gauge, unplug the PCB connectors from
the PCB, unscrew and remove the base plate and the controls
fascia panel from the appliance after disconnecting one end
of the restraining lead and the earth lead.
d) Isolate the cold water inlet valve and drain the DHW circuit by
opening all DHW taps.
e) From underneath the appliance, remove the two spring clips
securing the bypass pipe, and pull out the pipe. (Collect any
discharged water).
f) Unscrew the two socket head cap screws supporting the heat
exchanger (from above the heat exchanger - see Figure 37)
and push the heat exchanger downwards to release it.
(Collect any discharged water).
g) Replace the heat exchanger, then re-assemble in reverse order,
ensure the ’O’ ring seals are correctly positioned, and re-
commission the heating and hot water systems as explained in
section 5.
h) Check for leaks.
9.12 WATER FLOW REGULATOR
a) Remove the casing front panel and lower the controls fascia
panel as described in section 9.6 step (a).
b) Isolate the cold water inlet valve (see section 5.1) and drain
the DHW circuit by opening all DHW taps.
c) Make provision to collect any discharged water and unscrew
and remove the large brass nut (Fig. 37) supporting the
regulator assembly.
d) Unscrew the small nut at the opposite end of the assembly and
carefully remove the plastic water regulator. Replace the water
flow regulator. Ensure that the regulator is the correct way
around (Fig. 37). The filter should be cleaned.
e) Carefully re-assemble in reverse order then re-commission the
DHW circuit as described in section 5.