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38
REPLACEMENT OF PARTS
Manual No. 405/0101
REPLACEMENT OF PARTS - PAGE 38
9.21
TO REPLACE THE SAFETY VALVE
Refer to Fig. 44.
1.
Gain general access as described in section 9.1,
paragraph 1.
2.
Remove the screw securing the control box, see Fig. 25
and lower the control box.
3.
Drain the system.
Note:
When the system is drained, filled or vented, the
manual lever on the right hand side of the diverter valve,
see Fig. 27, must be moved to the 'MAN OPEN' (top)
position. Return it to its original position after the system
has been filled and vented.
4.
Remove the pressure sensor capillary from the safety
valve body.
5.
Disconnect the flexible pipe at the opposite end to the
expansion vessel. This is a hand screwed connection
with an 'O' ring seal.
6.
Undo the left hand pump union.
7.
Undo the union underneath the by-pass valve.
Fig. 44
8.
Undo the 28 mm system return connection below the boiler.
9.
Undo the 15 mm safety valve discharge connection below the boiler.
10.
Remove the backnut and washer securing the system return pipe to the manifold bracket and withdraw the pipe
complete with the safety valve attached.
11.
Undo the union and remove the safety valve from the pipe.
12.
Fit a new safety valve and reassemble with new sealing washers.
13.
Fill the system and vent the boiler as described in section 3.16, paragraphs 2 to 5. Check the safety valve connections
for water soundness.
14.
Reassemble the boiler as described in section 9.2, paragraphs 5 to 9.
15.
Refer to the Lighting Instructions, section 8 and light the boiler.
9.22
TO REPLACE THE BY-PASS VALVE
Ensure that the system is drained.
The by-pass valve is positioned to the left of the pump. The valve is pre-set for each particular model, ensure the boiler
model is quoted when ordering a spare.
1.
Gain general access as described in section 9.1, paragraph 1.
2.
Drain the system.
Note:
When the system is drained, filled or vented, the manual lever on the right hand side of the diverter valve, see
Fig. 27, must be moved to the 'MAN OPEN' (top) position. Return it to its original position after the system has been
filled and vented.
3.
To gain access to the rear by-pass valve union, the pump may have to be removed. Refer to section 9.18, paragraphs
2, 4 and 5. However, it is possible to access the union using a long stemmed spanner.
4.
Undo the union below the by-pass valve, then undo the union securing the 15 mm pipe on the back of the valve to the
main heat exchanger pipe. Take care not to twist the pipework. Remove the valve and transfer the 15 mm pipe to the
new valve using a new washer.
5.
Fit the new valve, using a new washer at the bottom connection.
Note:
The spare by-pass valve is pre-set and
must not
be adjusted.
6.
Reconnect the wires to the pump - Brown to L, Blue to N and Green/Yellow to , then replace the pump using two new
sealing washers.
7.
Fill and vent the boiler as described in section 3.16, paragraphs 2 to 5. Check the unions for water soundness.
8.
Reassemble the boiler as described in section 9.2, paragraphs 5 to 9.
9.
Refer to the Lighting Instructions, section 8 and light the boiler.
