hi there,
I remember reading something on this forum about how to test a boiler pump.
it's one of these Worcester 15-60 Pump Head 87161135940 Worcester 15-60 Pump Head 87161135940
the manual is http://www.bhspares.co.uk/wp-content/themes/RevampV3/manuals/Worcester%20Bosch/RD%20532i.pdf...