9.3.3 Flow and return sensors
There is one sensor on the flow (red wires) and one sensor on the return
(blue wires).
1. After noting the position of each sensors, prise the sensor clip off the
pipe and disconnect the plug.
2. Connect the plug to the new sensor and ease the clip onto the pipe
in its original position.
9.3.4 Safety overheat thermostat
1. Pull the two spade connections off the safety overheat thermostat.
2. Remove the screws securing the thermostat to the mounting plate
on the flow pipe and remove it.
3. Fit the new safety overheat thermostat to the mounting plate with the
two screw previously removed.
4. Connect the two spade connections to the safety overheat thermo
stat ensuring that they are pushed fully on.
9.3.5
DHW temperature sensor (NTC)
1. Turn off the mains cold water supply tap and draw off the residual
domestic hot water.
2. Ease the retaining tab on the sensor away and disconnect the elec
trical plug.
3. Unscrew the sensor from the plate heat exchanger manifold. Exam
ine the sealing washer, replacing if necessary.
4. Reassemble in reverse order with the new sensor. The plug will only
fit one way.
9.3.6 Pressure Gauge
1. Drain the primary circuit and undo the nut on the pressure gauge ca
pillary.
2. Ease the two retaining tabs holding the pressure gauge bracket
away and remove the bracket.
3. Remove the gauge assembly.
4. Examine the sealing washer on the pressure gauge capillary, re
place if necessary.
5. Reassemble in reverse order with the new pressure gauge.
Fig.57 Remove flow and return sensors
Fig.58 Removing safety overheat thermo
stat
Fig.59 Remove DHW temperature sensor
9 Maintenance
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