Glowworm fuelsaver- RGI has given up

[halton1957]

Hello folks, Hope someone can help with a diagnosis, My RGI is beaten but will carry out repair if I can identify the fault.
The boiler is Glowworm Fuelsaver 35f.

Briefly, It fires up normally and runs for 33 secs. then shuts down. After approx 90secs it fires up again and repeats the same cycle again.


He has fitted - new thermostat assembly.
new air pressure switch.
new Gas control valve assembly & solenoids

He has tested- Over heat cut out - OK

He says that when the fan shuts down there is still 240v at the PCB contacts supplying the fan, but cannot check at the fan as boiler is room sealed.

All the external timers/ room thermostats are OK and calling for heat.

HELP! It's getting colder.

 

[ScottishGasMan]

You need to get a different RGI, someone possible more experienced in fault finding. Boilers don't come an awful lot simpler than these.

 

[ScottishGasMan]

I don't mean to sound overly negative, but you simply cannot diagnose the fault on the via the internet, the checks and tests required mean working on the boiler which unless you know what your doing could lead to the boiler becoming very dangerous.

Also be careful how much you spend having someone attempt to repair it, these boilers are old obsolete models, with some unavailable spares, don't want to spend £££ only to find out the bit that's actually faulty is not available.

 

[TCCHeating]

He doesn't seem to have looked at the first thing I would have checked. Which is not part of the boiler, but a seperate component. As scottishgasman said, simple boiler, and simple fault finding. Get a new rgi with more experience

 

[Dan Robinson]

+1

I doubt it is a boiler problem from the sounds of it.

 

[gas112]

If the pump stopped on a fuel saver or was running slow the boiler would sound like someone is hitting it with a hammer as its low water content and would quickly boil.

 

[halton1957]

Thanks Scottishgasman, Yes I realise his limitations, I am a retired aircraft engineer which does not allow me to repair my boiler,
I quesstioned his decisions (diplomatically) and kept out of the way while he worked.
It has now cost me quite a lot of money to get nowhere ,it's Friday so nobody will do anything till Monday. So I'm hoping for a little relevant advice on the symptoms of the problem. The last thing I need is another RGI going through the same procedures

 

[gas112]

When it stops and he is getting 240v at pcb pins for fan can you still hear the fan spinning or not

 

[halton1957]

Thanks all, The pump is definitely running and sounds normal to me.

Gas 112, thanks for your input, Can't hear or feel the fan but pump is very close (and running on) as the fan should I believe.

 

[TCCHeating]

Feel the flow pipe from the boiler. When the boiler cuts off does it cool quickly?

 

[halton1957]

I realise the problems with spares etc on an old boiler but it's in good nick generally and a new boiler would involve upgrading gas supply from half inch to 3 quarters, it's under a concrete floor from front to back of house with no real alternative route for pipework. It's the wrong time of year to be without heat, but I guess it's colder further north.

 

[gas112]

Power leaving board to fan so next step would be is power being received at fan if so and fan not spinning then its the fan.

Been a while since i worked on one but pretty certain they work with case off so it will go through all the sequence for testing if power is at the fan and if its workingor not

obviously a job an rgi should be doing and only run in short bursts .

If fan doesnt make the air pressure switch then no power will go to gas valve

 

[Dan Robinson]

Doh. Misread the OP. Didn't realise the fan was still getting power.


Apologies.

 

[TCCHeating]

Doh. Misread the OP. Didn't realise the fan was still getting power.


Apologies.

I saw that but took it with a pinch of salt. Thats what the engineer said but is he right?

 

[halton1957]

Doh. Misread the OP. Didn't realise the fan was still getting power.


Apologies.

I saw that but took it with a pinch of salt. Thats what the engineer said but is he right?

As far as I can say, yes, he had his multimeter probes in the pcb connector. Obviously it wouldn't have been wise for me to interfere then. But I saw 240v reading.