no code showing,but the boiler fires up then shuts down at 86 degrees, it then fires again at around 70 degrees.the flow pipe gets warm for about 2 ft but not flowing,return stays cold as do all rads.pump is working and the pump impeller is ok.hot water side is ok.any ideas on this problem.thanks.

ken.

ken, December 2008

thanks,will purge the system but found no air last time,no valves on the system,apart from boiler isolating valves.will let you know results.
ken.

ken, December 2008

you either have lots of air,need purge and water or valves closed,for example zone valves.

old guy, December 2008