Alpha CB50 Boiler Hardware Replacement Manual

Instructions for replacing the electrically
operated automatic flow regulator with
the mechanical flow regulator valve

1. GENERAL

Ensure that the following instructions are carried out before replacement begins.
a. Isolate the electrical and gas supplies to the boiler and turn off the mains water supply.
b. Gain access behind the case and to the PCB as described in the Installation and Servicing instructions.
c. Connect a hose to the cylinder drain valve and drain the cylinder to outside.

2. REMOVE THE ELECTRICALLY OPERATED FLOW REGULATOR

a. Disconnect the flow regulator plug and socket located within the PCB enclosure. Unplug the wiring connectors
M1 and M13 from the PCB, see Fig. 2.
b. Remove the two white wires from the connectors M1 and M13. This can be achieved by pressing the tab in the
side of the plug and at the same time pulling the wire from its socket, see Fig. 2.
c. Remove the regulator's thermostat (located behind the DHW expansion vessel) and cable by removing the lower
front right hand side casing screw and sliding the thermostat to the right, releasing it from the retaining clip on the
cylinder, see Fig. 3.
d. Replace the connectors M1 and M13 into position on the PCB and re-assemble the control panel rear cover.
e. Secure the right hand side casing panel with the screw previously removed.
f. Disconnect the mains inlet valve and cylinder union connections from the regulator valve and remove the
regulator. Remove the filter from the regulator and retain, see Fig. 4.
NOTE: All parts removed must be returned to Alpha detailing the CB50 boiler serial number which is located
on the hinged control panel cover.
Alpha CB50 Boiler
Fig. 1 - Kit Contents
Union bend (A)