Hi,
My oil-filled heating system isn't working. I have an external Grant combi-boiler, and suddenly, 3 days before Christmas, the heating stops working. I still have hot water, but the temperature is fluctuating. It will get properly hot, but then gets luke warm after about 2 seconds, before getting hotter again.
I have my boiler serviced and repaired regularly (can't get in touch with my usual plumber), and have had a new Grundfos heating pump probably a year ago. I had a new burner maybe 18months ago.

Does anyone have any suggestions, or does this sound like a classic case of something or other, and is it likely to be something I can fix?

bigstick, December 2008

if boiler fires for only a couple of seconds and the pipes get very hot normally this sugests pump problems,if hot water still works that may be running on gravity circulation hence you get hot water,if pump runs you may have a problem with port valve stuck closed the micro switch tells the boiler to fire but valve is stuck closed

bishop plmbing & heating (wiltshire), December 2008