I think there is something wrong with my thermostate, as the heating was coming on and off at it's own pleasure! Now it is flashing -//- and I have no heating, but have hot water?

KC, November 2012

Is the electrical supply to your boiler OK? If it's being interrupted, that caould cause the cycling you are seeting. get someone who knows enough about electrics to do it safely, to have a look.

trevor, November 2012

Did a search for "Worcester Bosch 37cdi fault indication"

Found an instruciton manual and a servicing guide. See

http://www.acwilgar.co.uk/user-manual-for-greenstar-cdi.pdf

and

http://www.theplumbstore.com/downloads/dl/file/id/1331/installation_and_servicing_instructions_for_greenstar_cdi_part_1_of_2.pdf

plus

http://www.theplumbstore.com/downloads/dl/file/id/1332/installation_and_servicing_instructions_for_greenstar_cdi_part_2_of_2.pdf

Read the first PDF (http://www.acwilgar.co.uk/user-manual-for-greenstar-cdi.pdf) and you will see, on page 13:

• The boiler runs for 15 minutes at minimum heating output to fill the condensate trap, the display alternates between “-II-” and the central heating flow temperature. This occurs every time the mains supply has been interrupted.

Switch on, leave for at least 15 minutes and see if the teperature comes up to normal after the safety cycle has completed.

Anon, November 2012