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29. THE SAFETY VALVE
Fig. 27.
(a)
Drain off the central heating and domestic hot water systems.
(b)
Unscrew the safety valve from the feed and vent pipe taking
care not to distort the pipe.
(c)
Fit a new safety valve using an approved jointing compound.
(d) Open all the radiators and fill the system, venting as necessary.
The appliance is fitted with an automatic air vent on the heat
bank
30. THE DIVERTING VALVE
Fig. 30.
(a)
Drain down the central heating and domestic hot water
systems.
(b) Disconnect the diverting valve leads at the terminal strip. See
Fig.
11 .
Release the strain relief bush and carefully withdraw
the leads from the control box.
(c)
Loosen the top connection on the diverting valve and
disconnect the other end of the elbow. Take care not to mislay
the washer.
Fig. 30.
Domestic hot water pump
(d) Release completely the left hand heat exchanger union
connection taking care not to mislay the washer.
(e)
Release the remaining two union connections on the valve.
Carefully rotate the connector pipe between the diverting
valve and the heat exchanger to allow it to be drawn away
from the diverting valve.
(f)
Lift the valve upwards and to the left to separate it from the
pipes.
(g)
Fit the replacement diverting valve with the manual override
lever facing downwards.
(h) Reconnect the leads ensuring that the strain relief bush is
replaced. Refer to the electrical wiring diagram (Fig.
11)
to
ensure the correct connections have been made.
(i)
Open all radiator valves and refill the system, venting as
necessary. The appliance is fitted with an automatic air vent on
the heat bank.
(j)
Check that the system operates satisfactorily.
NOTE. It is possible with some diverting valves to replace the
operating mechanism only, leaving the valve body in·situ.
Consult the diverting valve manufacturers instructions for
further information.
Diverting valve
Pressure gauge
25
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