Vaillant boiler: works fine for radiator, but only sometimes for hot water

FreeBear

Brokenlynx said: Sorry if the above is a little vague or unfocussed in terms of the questions but in short, I'm looking for what I should be researching in the time between now and a potential boiler failure. 

First thing to look at is the routing of the gas pipe - It looks like it is currently 15mm. Any new boiler may well require  22mm pipe (possibly larger), so look at the practicalities of installing a new pipe all the way back to the meter.

A condensate pipe will need to be fitted - Preferably connected to a drain internally (from the sink perhaps). This may necessitate pulling some of the base units out. Alternatively, a hole could be drilled through the wall and the condensate pipe routed to a dedicated soakaway.

ThisIsWeird

...and don't use BG.

FreeBear

ThisIsWeird said:

...and don't use BG.

Or Eon - They'll flog you a WB boiler with a 5 year guarantee (although you can upgrade to a 7 or 10 year for an additional fee).

A local independent installer will be up to £1K cheaper and should be able to provide a 10/12 year warranty at no extra cost.