In message . com, Agile
Services writes
The original poster seems to have a diverter valve which is starting to
fail. The boiler should switch on with about 2.5 litres per minute
flow.

The other posters have not given enough information but probably have
blocked secondary heat exchangers. Run a hot basin tap and if the
temperature gauge shows more than about 65 C then its partly blocked.
This usualy cycles on off every 15-20 secs or so.

If the temp stays below 65 C then there might be a problem with the
fan/venturi/aps. This cycles on/off much faster every 4-5 secs
typically but needs a competent CORGI engineer.

These boilers are sold at a very reasonable price and are perfectly
serviceable boilers but are bought by cowboys and the non registered
and usually badly fitted without cleaning the system.

What's this Tony, subscribed to uk.d-i-y now ?

Welcome on board

--
geoff