Is this boiler "fault" normal - video

[chrisw99]

Does it only do it on HW or does it do it with the CH on too ? I certainly do not think that a powerflush has anything to do with it.

It does it with the CH on as well, but it just takes a hell of a lot longer to get to that situation as I have to wait for the whole system to heat up.

The video above was when I turned the CH on, 2 hrs after I'd had the boiler on for hot water.

The problem is, now BG have diagnosed the blockage in the DHW flow/return and recommended a £700 powerflush, they won't visit us again till we've had that done. Which is why I'm trying to find out if what is happening IS normal if there's a blockage in the DHW flow/return, as I don't want to have to spend loads of money to then find out a new boiler is required (which would probably include a flush, or more likely be a combi rendering the blocked DHW pipes useless).

The only thing I can say with any certainty as regards a pattern is
IF the boiler hasn't been on for more than 2-3 hrs , it fires up fine
IF the boiler has been on in the last 2-3 hrs, even if it's cooled, it takes many many attempts to light.

 

[picasso]

Get the ignition gas pressure checked, could also be blocked gas valve or faulty meter governor.

 

[ianmcd]

You do not need a power flush, you could possibly benefit from one who knows, but a power flush will not sort the problem that you have, BG are absolutely terrible for doing this and you will be £700 lighter and the fault will still be there, call their customer services department and tell them that you are contacting the boiler manufacturer for a fixed price repair, and that if they can repair it without a power flush then you will expect them to pay the bill, and if they cant repair it then you will go with the power flush, I havent seen your boiler but no way will a power flush fix that. BG engineers are under a lot of pressure to sell stuff that you do not need and power flushes are their favourite

 

[chrisw99]

You do not need a power flush, you could possibly benefit from one who knows, but a power flush will not sort the problem that you have, BG are absolutely terrible for doing this and you will be £700 lighter and the fault will still be there, call their customer services department and tell them that you are contacting the boiler manufacturer for a fixed price repair, and that if they can repair it without a power flush then you will expect them to pay the bill, and if they cant repair it then you will go with the power flush, I havent seen your boiler but no way will a power flush fix that. BG engineers are under a lot of pressure to sell stuff that you do not need and power flushes are their favourite

With the DHW flow blockage, surely the boiler manufacturer will likely fall back on me having to sort that out first? And if that's the problem, I'll be paying another fixed price to them for the same diagnosis (assuming they'd only fix boiler faults not clear system blockages?)

I guess I need to give it the 10-14 days the BG guy said the Fernox F5 will take to clear the blockage, if it clears it, first. It's only been 5 days. And then try and clear the blockage manually if I can.

And it may be my imagination, but I'm sure it's getting better slightly each day (based on the totally unscientific method of seeing how long it takes for my left hand to get hot when reaching up the pipe as far as I can with the right hand feeling the boiler output).

In fact, just got home from work and the boiler fired up first time. I've currently got the CH coming on from 1pm till 5pm when no ones in as the F5 needs the CH hot and flowing to work, so it's only been off 2 hours. Yesterday it did the cycling problem, today it worked.

 

[ianmcd]

its not a flow problem, its a rectification problem, I cant tell you more than that as site rules prevent it, BG do this constantly, they are an absolute nightmare.

 

[chrisw99]

its not a flow problem, its a rectification problem, I cant tell you more than that as site rules prevent it, BG do this constantly, they are an absolute nightmare.

Ok, interesting. Is there any way to rule out a flow problem 100% though? In the past, when the pipe at the boiler got hot, the pipe up at the cylinder used to get hot within a minute or two. I remember this from 15 years ago when the cylinder was replaced and we got an airlock, seeing how long the heat rose. Now the first maybe 12 inches of flow from the boiler are too hot to touch, but it takes a couple of minutes before the pipe 3 or 4 feet away is too hot to touch, and 5 or 6 before it's hot up at the cylinder.

If it was a rectification problem (whatever that is) and there was no flow problem whatsoever, would that cause the heat to move away from the boiler so slowly?

 

[ianmcd]

if it was a blockage then the burner would never stay lit for long, you said it eventually stays lit so it is not a flow problem, if it was a flow problem you would hear the boiler Kettling (sounding like a kettle boiling before cutting out )

 

[chrisw99]

if it was a blockage then the burner would never stay lit for long, you said it eventually stays lit so it is not a flow problem, if it was a flow problem you would hear the boiler Kettling (sounding like a kettle boiling before cutting out )

That's actually exactly what is happening (check my sequence of events post). When I say it stays lit I mean stays lit longer than 1 second, probably for 2-3 mins until kettling occurs and then cutting out because the flow temp has reached 60C. (in HW mode, in CH mode it stays lit a lot longer because the CH pump is pulling it away from the boiler)

BG engineers are under a lot of pressure to sell stuff that you do not need and power flushes are their favourite

To be fair to the BG engineer he recommended a powerflush but said "not with us, we're too expensive" and told me to shop around or hire the equipment and do it myself.

 

[ianmcd]

you never at any time have mentioned kettling

 

[chrisw99]

you never at any time have mentioned kettling

Please see post #12. Point 3...

 

[kidgreen61]

My advice would be to arrange the following words into a logical sentence:

Boiler, wall, from, skip,in remove, deposit, in.

 

[chrisw99]

My advice would be to arrange the following words into a logical sentence:

Boiler, wall, from, skip,in remove, deposit, in.

That's in my plan, the wall the boiler is on is in the garage and is damp and falling down, with an asbestos roof. I plan to get the whole garage rebuilt in a year or two which will involve replacing/relocating the boiler and most pipework. Simply can't afford it at the moment.

Until then, I need to keep this one going

 

[ianmcd]

Google or search on here for blocked cold feed

 

[chrisw99]

Google or search on here for blocked cold feed

I have read about that, but at weekend I opened up the drain cock and the F&E tank feed starting filling fast so I guess the cold feed is ok? Didn't want to leave it too long, the F&E tank has 15 years of gunk in it. In fact the first step in me figuring this out this coming weekend is cleaning out my F&E tank ready for a drain of the system. The water is black. And I guess I need to drain the Fernox F5 even though the BG guy said it can be left in forever. Don't really fancy all that dissolved sludge travelling around forever so going to do a couple of drain and refills.

 

[Dan Robinson]

I opened up the drain cock and the F&E tank feed starting filling fast so I guess the cold feed is ok

Means that two of the three ports are free. That is all.