central heating ideal boxer combi problems

[4656steven]

hope someone can help
i have an ideal boxer combi boiler 5 years old i emptied the system flushed it through filled it up with clean water and now i only have hot water the heating system does not work.
The boiler heats up for about 30 seconds the temprature guage shoots up then the boiler shuts off the heating, there is slushing noises coming from the top of the boiler there is no heat coming through the pipes this suggests trapped air but i have checked all radiators and the pump there is no trapped air there am i missing something. (i have tried bleeding the system twice) please help with any advise would be appreciated
Thanx
Steve.

 

[cider]

obviously air lock in boiler itself may be auto vent in boiler stuck but you need to take front off to get in which you may not fancy doing. best bet is to keep running boiler in heating mode but switch demand off before or immeadiately after it fires up by turning stat down not turning complete boiler off. this will stop boiler overheating but hopefully will get the pump to run on for a minute or so. this might shift it .

 

[4656steven]

Thanx for that cider i have tried what you have suggested.
What does the autovent looklike and how do i get it to open please.

Thanx in advance
Steve.

 

[shambolic]

I am sure the Boxer is the same as an Europa which has the (in)famous diverter valve thats in potterton 80s too the valve sticks(more of a wax capsule type thermostat in operation) not allowing the heat to go down the rads.
Bit of a job to replace, sorry

 

[shambolic]

try this from a few years back
//www.diynot.com/forums/viewtopic.php?t=72490

 

[4656steven]

ok chaps thanx for the advise so far
heres where im at i have bled the system again and refilled it this time there is no air blockage in the boiler.
So its either the diverter or the pump there is a smal buzzing noise from the pump when its on but can't be sure its pumping around when the boiler shoots up in temp the outlet pipe gets hot but only for about 4 inches from under the boiler, not sure how i check either to be sure ?
does anyone know how much i should be looking at to get in a heating engineer and replace either the diverter or the pump ?

Thanx in advance
Steve.