Is this my boiler or the radiator valves

[tanker]

Hi guys,

Wonder if you could answer a question I'm having. I have a Sime Friendly Format 80E, I noticed that when putting the heating on this year the radiators aren't as getting as hot as they once were, what was noticed was that the radiators were hot at the top and cold towards the bottom. At first I suspected that I might have a sludge problem but the system is only about 5 years old so not sure this would be the case.

I did happen to look at my boiler and noticed that the boiler fired up for about a minute then went out for a minute or so (pump still running), it then fired up and went out, over and over again. All in all the boiler was only really heating the water in the system for about 50% of the time it was on. Do you guys with experience think I have an issue with the boiler or the radiators? Any advice would be appreicated.

If it helps the hot water appears to function properly.

T

 

[southernnrg]

sounds like a restricted flow issue, boiler getting up to temp too quick, what is your temp setting on the boiler set to?

 

[compheat]

Im not very familiar with this combi, but it sounds to me that the burner is coming on and not rectifying back to the pcb and just keeps on trying to relite the burner. or possibly the diverter valve sticking.

Others on this forum will soon put me right

 

[tanker]

Guys

Thanks for the advice, I was going to mention that the flow and return pipework leading from the boiler reduces to 15mm soon after leaving the boiler. I thought this might have been the issue but it worked well last year so can't see why it would suddenly be a problem?

I did notice that the time the boiler was on seemed to disminish as the system heated up, so you might be on the ball with the flow thing. Could this be true for the PCB issue as well?

 

[olejim]

It is a flow issue. Remove the rad which shows the worst of symptoms, and flush it, see what comes out of it. My money is on loads of rust, not sludge, my guess is you have cheap rads or somebody forgot to put inhibitor in the system. If they are cold at the bottom you cant be seriously thinking that the boiler has developed a malfunction.