40
Part No. 5106463
Servicing & Maintenance
Pressure Relief Valve
1. Drain the boiler using the boiler drain point provided.
2. Undo the compression fitting connecting the
discharge pipe to the relief valve.
3. Undo the pressure gauge sensor retaining nut and
withdraw sensor from the relief valve, taking care
not to lose the fibre washer seal.
4. Undo the union nut at the rear of the relief valve
and pull the relief valve clear of the pipework, taking
care not to lose the fibre washer seal.
5. Fit a replacement valve in the reverse order.
6. Fill the system as described in Section 2 - Pre-
Installation Requirements.
Circulating Pump
1. Remove the pump electrical cover and disconnect
the electrical leads taking note of the wire positions.
2. Turn off the isolating valves mounted on the inlet
and outlet of the pump. Undo the two union nuts
and remove the pump from between the pipework.
Note: A residue of water will remain in the pump.
3. Fit a replacement pump with new sealing washers.
Note: The direction flow indicator on the pump
should point from left to right.
4. Open all valves and fill the system as described in
Section 2 - Pre-Installation Requirements.
Expansion Vessel
1. Drain the boiler using the boiler drain point provided.
2. Undo the nut connecting the vessel to the flexible
pipe from the boiler.
Take care not to lose the fibre washer seal.
3. Undo the two nuts retaining the expansion vessel
assembly bracket to the boiler, lift bracket up and
out, remove from boiler.
4. Remove top retaining arm, lift vessel up and out off
bracket assembly.
5. Fit a new expansion vessel in reverse order to
above.
6. Fill the system as described in Section C - Pre-
Installation Requirements.
System Pressure/Temperature Gauge
1. Drain the boiler using the boiler drain point provided.
2. Turn off the isolating valves mounted on the inlet
and outlet of the pump.
3. Undo the nut retaining the pressure gauge sensor
from the pressure relief valve. Remove sensor,
check fibre seal, replace if damaged on
replacement of new sensor.
4. Remove the clip and withdraw the temperature bulb
from its pocket.
5. Un-clip the temperature/pressure gauge from its
bracket, remove gauge, carefully withdrawing
sensor and bulb capillary tubes through bracket
assembly.
6. Fit a replacement gauge in the reverse order.
7. Open the valves and fill the system as described in
Section 2 - Pre-Installation Requirements.
Diverter Valve (Flowsure/F)
1. Drain the boiler using the boiler drain point provided.
2. Turn off the isolating valves mounted on the inlet
and outlet of the pump.
3. Undo the electrical plug retaining screw on rear of
control box lid and disconnect electrical plug.
4. Disconnect the electrical lead from the connection
plug, taking note of the wire positions.
5. Undo the two screws, retaining the central heating
flow pipe to diverter valve, gently pull pipe away
from diverter valve.
6. Undo the two screws, retaining the DHW flow pipe
to diverter valve, gently pull pipe away from diverter
valve.
7. Undo the two screws, retaining the pump to diverter
pipe, remove diverter valve from pipe assembly.
8. Fit a replacement diverter valve in the reverse order,
taking care to check and replace if necessary the
“O” ring seals, fitted to the pipe tail ends.
9. Open the valves and fill the system as described in
Section 2 - Pre-Installation Requirements.
Flow Switch (Flowsure/F)
1. Close the mains water isolation valve to boiler.
2. Close the domestic service cock on the mains inlet
pipework of the boiler.
3. Drain the residual water from the hot water
pipework.
4. Undo the electrical plug retaining screw on rear of
control box lid and disconnect electrical plug.
5. Disconnect the flow switch electrical lead from the
connection plug, taking note of the wire positions.
6. Undo the nut connecting the flow switch to domestic
service cock pipework.
7. Undo the nut connecting the flow switch to water to
water heat exchanger pipework.
8. Pull the nuts back and extract the flow switch.
9. Fit new flow switch and new fibre washers in the
reverse order, ensuring the flow switch head is
inclined at least 15° above horizontal and will not
foul the top casing panel. The direction flow
indicator on the flow switch head should point in
the direction of the water to water heat exchanger.
10. Open the domestic service cock and mains water
isolation valve, turn on hot water tap, check
connections are sound.
