Glowworm fuelsaver- RGI has given up

[halton1957]

Do you mean a blocked feed pipe from boiler to pump?

No I mean the usually 15mm pipe feeding water from the F&E tank into the >>>>

I guess a Myson aerjec is the separator you refer to?

Yes that one!

If a magnet sticks to where this feed enters it you know it will be chocka with crud.

Thanks for that Slugbaby, A fairly powerful magnet sticks anywhere on the Aerjec, I guess take it out and fit new is better than trying to clean it out?
What is the reasoning behind that test? Oxides from the rads?


Added later- Magnet also sticks to the pipework in that general area, especially the horizontal runs - More crud?

Added next day-Drained down and took pump head off again, inside all black, I think its made like that. No sign of rust but haven't removed shut off v/vs.

Spent a few hours removing shelves and door of compartment to allow good access for unsoldering air seperator, provided the plumber is happy for me to do so. I know I didn't like putting things back together when someone else had dismantled them.

 

[Slugbabydotcom]

Where the feed enters the system; that section of water is relatively static. This is where the black crud usually settles. The black crud aka Magnetite as the name suggests is magnetic. It is what occurs when iron tries to rust but there's not enough oxygen.
Seems like your system is seriously crudded up. Ideally it's time to rip the lot out and start again if the magnet sticks to other sections of the pipe. But at the least a powerflush and a Magnaclean. Replacing the affected section should hopefully give you time to save up in the meantime.
It's not impossible that there could be another blockage somewhere and the next suspects are the inlet or outlet port of your pump, a low section of pipe or a source of air ingress such as a leaking rad valve that stops leaking when your system is on.

 

[DanTheGas]

Hi. Going to jump in on this.....

A) You should not be able to stop your pump with your finger! That is a pump with no torque and it needs replacing.
B) Magnetic pull indicates iron oxide; hence the "stick" of a magnet.... This is sludge and a system of this age; will have sludge.
C) if you have a de-aerator; don't replace, remove and pipe up as a close coupled H configuration; the system is old, don't complicate things.
D) A fan can stop when hot; as the boiler temp raises, the coil expands along with the core and all the other metals and can expose weakness in the windings which pull apart and the fan stops.


Change your pump, then fan.... In all honesty; you need a new boiler... Completely irrespective of gas supply difficulty, don't waste more than a £100 on this boiler; its uneconomical, by doing all this you are prolonging the inevitable.

 

[halton1957]

Hi Slugbaby, you were up early, or was it to bed late? Anyway thanks for your input. Bearing in mind what Dan has posted this morning, the easiest thing to eliminate is the pump so I guess doing that before sweating out the air seperator is the way to go?

 

[Agile]

From what you have said you have removed the pump head but not done the finger test, see FAQ.

Tony

 

[halton1957]

From what you have said you have removed the pump head but not done the finger test, see FAQ.

Tony

Hi Tony, thanks for your reply, Looked at the specs of the pump. It's Grundfos alpha (not 2) 15-60 130mm. It says automatically variable - could that be why my finger stopped it?
What FAQ do you mean please.

Later- found FAQ.
Pump was easy to stop- bad sign?

 

[breadnbutter]

i been to these were the fan runs for 2 mins and dies, then restarts 3 mins later, it was the fan windings. replaced fan. fixed.
not excactly saying thats the fualt on yours, but mentioning 240 to fan,not rotating.plus it running for short time, and no over heating,pump,tank ,rads bled.
the fan is a strong possibility.
obsolete parts now. hard to find. fleebay maybe.

get r.g.i out to fit,for your safety.

 

[Agile]

Nothing you have said yet indicated that the boiler may not just be working correctly and switching off because it has reached the set stat temperature.

We have only just learnt that you have a smart pump.

Can you set the pump so that it pumps harder?

Tony

 

[gas112]

Yes he has he said 240v coming out of board for fan an fan is not spinning

 

[Agile]

But the next post he said there was still steam coming out of the flue!

 

[halton1957]

Nothing you have said yet indicated that the boiler may not just be working correctly and switching off because it has reached the set stat temperature.

We have only just learnt that you have a smart pump.

Can you set the pump so that it pumps harder?

Tony

Hi Tony, Pump is at max.

 

[halton1957]

Yes he has he said 240v coming out of board for fan an fan is not spinning

RGI said 240v, & fan not spinning. I'm not so sure.

 

[halton1957]

But the next post he said there was still steam coming out of the flue!

I did think this was the case but difficult to get outside at the right moment, could have been residual steam rather than fan blowing it.

Got a second RGI coming this afternoon, hope he can throw more light on the situation.

 

[Agile]

It is difficult to compare these things.

I usually say that a man would be able to stop the fan with a finger but most women would not!

But for me a main indicator of the flow through the system is the temperature differential across the boiler.

More than 11 degrees would usually indicate a lack of flow on a non condensing boiler.

What you said about the fan was confusing! A sure way to know if a fan is working is the flow of air out of the flue!

Tony

 

[halton1957]

It is difficult to compare these things.

I usually say that a man would be able to stop the fan with a finger but most women would not!

But for me a main indicator of the flow through the system is the temperature differential across the boiler.

More than 11 degrees would usually indicate a lack of flow on a non condensing boiler.

What you said about the fan was confusing! A sure way to know if a fan is working is the flow of air out of the flue!

Tony

I appreciate what you're saying, but when I first talked about the fan I had little idea about the sequence of things. Now that I have listened carefully to things happening, I'm sure it goes like this.External timer & roomstat calling for heat, Power on, Boiler stat at max, pump at max, pump runs, fan runs, sparks, pilot lights, main burners light, all Ok for 90sec from cold, 30 sec if warm, fan stops, flames die down and become lazy and fully out in about 3 sec, pump continues running, after 3-4 mins the sequence repeats.
The pipework, pump etc get warm after 3-4 cycles of that. If it's left to it's own devices it will continue to cycle and after 3-4 hours the rads are very warm but not hot.
As said another RGI coming today so will report back.
To save people referring to past posts. The Boiler T/stat, Air pressure switch, and Gas valve complete assembly inc solenoids have been replaced. The overheat cut off has been tested & found OK. None of these changed anything. The boiler is still doing exactly as it was at start of problems.

Hope this helps.