Pump Head; Pressure Relief Valve - Viessmann VITODENS 200 WB2A Installation & Servicing Instructions Manual

9 Replacement of Parts

9.19 Pump Head

c)
Unscrew the four recessed hexagon screws and withdraw the pump head.
d)
Remove the single screw securing the electrical connection cover. Remove
and transfer electrical connections to the new pump and reassemble in reverse
order ensuring that the pump is adjusted to maximum speed (II).
e)
Connect the filling loop, open the CH flow and return valves and re-pressurise
the system to design pressure using the filling loop valves and venting as
necessary. Check all connections for soundness, and then disconnect the
filling loop.
f)
Finally, ensure that the outer casing is secured in position and carry out an
ignition and control check.

9.20 Pressure Relief Valve

a)
Gain access by following step 9.1(b).
b)
Isolate the central heating circuit by closing the flow and return valves. Drain
the appliance using the drain point situated underneath the appliance at the
bottom right hand side.
c)
Disconnect the pressure relief valve outlet connection and unscrew the union
behind the pressure relief valve and the coupling to the left of the valve
between it and the by-pass pipe.
d)
Replace the pressure relief valve and reassemble in reverse order.
e)
Connect the filling loop, open the CH flow and return valves and re-pressurise the
system to design pressure using the filling loop valves and venting as necessary.
Check all connections for soundness and then disconnect the filling loop.
f)
Finally, ensure that the outer casing is secured in position warm up the system
and check for water leaks.
Supplied By www.heating spares.co Tel. 0161 620 6677
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