Boiler overheating problem

[Jpsmith]

Hello,

Any help on this would be greatly appreciated before I call out a professional, as I have tried every thing I can think of.
Basically I have a British Gas 330 condensing boiler and a y plan system. I have turned off the boiler, drained the system, refilled and removed air from all rads. When I turn the heating on the boiler heats up to 95 degrees very quickly then cuts out. Before cutting out it makes a lot of gurgling as if there is air trapped. The pump works and all radiators have no air. I have tried attaching hose to the lowest drainage valve on a radiator to try and release any air but this did nothing.
I am not sure what to try next
Thanks
James

 

[SimonG]

Bled the pump? Bled the coil?

 

[Jpsmith]

Hello I have bled the pump but not sure how to bleed the coil

 

[Aire]

The air/gurgling you hear before it cuts out is probably the water beginning to boil. Because the temp is rising so rapidly you clearly have very poor circulation. This can be caused by an airlock. Having drained down and filled back up, an airlock would be the first thing that comes to mind. But why did you drain down? Was you working on the system or did you drain down because you was having issues with air and believed this would cure it?

 

[Jpsmith]

Hello. I bled down to move a radiator to another close wall.

 

[Aire]

Hello. I bled down to move a radiator to another close wall.

Probably an airlock then, or it could be an ageing pump, it worked before when everything was fine but now you've added air into the system the pump may be to weak to force the air out, have you got a pic of your pump? And do you know how to tell if your pump is on its last legs?

 

[Jpsmith]

It is a mason cp53

 

[Jpsmith]

Sorry myson cp53 Not sure how to tell if it is it’s last legs

 

[king of pipes]

Air locked by the sound of it can be a pig to remove as above a weak pump will not help does it fill ok ? Did you lock open the 3 port when you filled and vented ? , turn the boiler thermostat down to minimum run the heating controls set to constant and try venting pump and radiators again place a container under the pump and loosen the chrome type nut you will get some spillage but should bear a slug of air travel around the system and hopefully eventually clear its self. Kop

 

[Jim09876]

Make sure your calling for HW only, use the fuse spur or pump control to pulsate the pump...10 secs on/10 secs off. Try this on different pump speeds etc. Can be something of a art to this and it can take the a while. Only once it’s returning round the HW circuit correctly...then open the heating circuit.

Dunno if I’m supposed to try help or not.

 

[Riley]

Course you can help Jim

 

[Last Plumber]

A domestic Circulator will not shift air by itself in a lot of cases.
Is this a sealed system or open vented?
Do you have solid floors downstairs?
Is the Boiler on the ground floor?
Just trying to visualize the set up a bit better!

 

[Darren Jackson]

There is a vent nipple inside the boiler on the flow pipe next to the overheat stat, but this will require the removal of the inner case seal and therefore it is illegal for a non GSR engineer to carry out this work. Best advice is to employ a local GSR to have a look once you have tried everything else and the problem still persists.

 

[Stu-B]

Could be the pump is spinning but the impeller blades are not turning.

 

[Jpsmith]

Hello,

Thanks for the replies. I took Jims advice and have now got flow and a couple of rads are heating up. I have tried the hot water but this doesn't seem to be working.
To give you an idea of house layout, it is a 3 storey house with the hot water cylinder and pump on the 1st floor with a condensing boiler on the bottom floor. It is an open vented system and there is a solid concrete floor slab down stairs with the pipe buried in it.
My next plan was to start turning rads off to try to get heat to the ones that are not coming on. I am hoping that this might help to sort the hot water problem but any advice oud be appreciated.
Thanks
James