Boiler keeps cutting out!

[Daveafsmith]

Hi everyone. Basically I have an old ikon 40 50 ci boiler. It recently started cutting out after 10minutes of heat. I thought it may be the pump so that has been changed. Still hasn't stopped it though. When it fire up it heats up the rad closest to the boiler for about 7 mins but no others(apart from a few days ago where it heated all of them up for 5 mins). When it has cut out it wont fire back on until its cooled down. I am thinking maybe a blockage? Or an air lock. Any help greatly received.

 

[Vee]

Sounds like circulation issue. So yes could be blockage or airlock. Any signs of pumping over into header? Or is it sealed?

 

[Daveafsmith]

Hi mate and thanks for your reply. I have drained the system down this evening. Refilled with some inhibitor and let it refill. Still no joy. Excuse my ignorance but what does pumping over into the header mean? There is a retro fitted piece of pipe work that goes lower than the rest of the pipework which I have mains jetted out this evening as well and the water was filthy but that still hasn't sorted it out. It's an open vented system. I really don't want to buy a new boiler as I think this is a good one when it works. Not actually that much that can go wrong with it really

 

[Ric2013]

Pumping over means water is forced up the open vent which finishes over the top of the feed and expansion cistern (or header tank) and dribbles into this cistern.

There is a retro fitted piece of pipe work that goes lower than the rest of the pipework

I don't follow.

 

[Daveafsmith]

No sign of that mate. Basically the guy who owned my house before me converted the garage in to a bedroom, installed a stupid fan thing that runs off the heating. The pipes for this are in the floor. So naturally the sediment will sit here. I blasted the pipes for this bit through this evening and still no joy. I have replaced the pump already so its either a circulation issue or the thermostat? Weirdly it's only the rad nearest the boiler that heats up before it stops.

 

[Ric2013]

You don't have a one-pipe system, by any chance? Could you previously turn off any one radiator without affecting the other radiators?

 

[Daveafsmith]

There is a flow and return at the boiler and there are a couple of loops which are dual piped..... the boiler won't even turn on for ages now. I am debating the pcb......

 

[Vee]

What controls set up do you have, i.e valves etc? Could be stuck valve only partially opening?

 

[Daveafsmith]

It's the standard 15 year old 3 way valve with a slider on one side. Controlled by the main heating controls. The boiler fired today but same issues. I will look into replacing this though. It's up on the list.

 

[Daveafsmith]

So. I drained it all down again. And she. I filled it back up I seemed to get a lot .ore air out of this time. Fired it up and it does again. Am I over complicating This? Could it just be the thermo cut out? The pipes do seem got but very hard to judge.

 

[Gary80gas]

what happens when you set it to just heat the hot water only?

 

[Daveafsmith]

Just waiting for it to fire up again once the temperature has come down
Today I have removed and flushed all the down stairs rads. One was particularly nasty. The rest were not too bad. Is it worth doing all the upstairs ones as well? Figured all the cheap would sit at the bottom.

 

[Ric2013]

It's what we used to do before someone realised there was money in selling us all powerflush machines. May not be quite as effective as a powerflush, but if you're happy to do it, do it.

 

[Daveafsmith]

what happens when you set it to just heat the hot water only?

It fired up. The rads got hot????? Then it died again.