Plate Heat Exchanger
Fig. 68
Rubber Seal
Sensing Pipes
Manifold
Microswitch
Bracket
Grub Screws
DHW Pressure
Differential Valve
Fig. 69
Diaphragm
Diaphragm
Spring
Plastic Disc
Pushrod
Fig. 70
12.0CHANGING COMPONENTS
12.20Plate Heat Exchanger (Fig. 68)
1.Drain the primary circuit.
2.While supporting the heat exchanger undo the screws securing it to the brass manifolds.
3.Withdraw the heat exchanger upwards and to the left of the gas valve, taking care not to damage any wires or controls.
Seals
4.There are four rubber seals between the manifolds and heat exchanger which may need replacement.
5.Ease the seals out of the manifold. Replace carefully, ensuring that when the seal is inserted into the manifold it is parallel and pushed fully in.
6.When fitting the new heat exchanger note that the left hand location stud is offset towards the centre more than the right hand one.
7.Reassemble in reverse order.
12.21Diverter Valve Assembly (Fig. 69)
The diverter valve assembly comprises of a central heating pressure differential valve and a domestic hot water pressure differential valve. These are connected to a manifold which is joined to the plate heat exchanger.
DHW Pressure Differential Valve (Fig. 70)
1.Drain the primary circuit.
2.Undo the screw securing the microswitch bracket to the valve (Fig. 69).
3.Disconnect the two sensing pipes and slacken the grub screws securing the valve to the diverter manifold.
4.Draw the valve away from the diverter manifold. The valve may now be replaced or split to examine the diaphragm.
5.To examine the diaphragm hold the valve body securely and carefully remove the six screws. The diaphragm spring will force apart the two halves of the valve.
6.Remove the plastic disc and pushrod assembly. Carefully examine the diaphragm and replace it if there is any damage.
7.Reassemble in reverse order.
36 | Publication No. 5111811 |
