Grant Oil Boiler, Riello RDB1 burner, intermittent lockout

[reb78]

As above, I have a Grant boiler with an RDB1 Riello burner (have three actually.. but one is playing up).

It locks out intermittently. Pattern currently seems to be that it will come on, heat up the cottage to 18C when the stat cuts out and then it wont start. It has either locked at at the end of the last burn or start of the next one. Hard to know which.

So far:
- New nozzle fitted - old one looked fine tbh
- Have checked the boiler setup - pump pressure, flue gases and adjusted according to the manufacturers instructions for the nozzle, burner and boiler unit.
- The pump is about a year old so virtually new
- Boiler baffles all removed, internals cleaned and all sealed properly (its external but did have a leak before the flue from the access plate. Sealing hasn't altered the lockout)
- solenoid replaced
- photocell replaced
- oil flow seems good. Bit of gunk in the line so we disconnected both ends and blew through with a compressor
- tank was replaced last year, empty and clean so shouldnt be residual water or muck in the lines anyway

Plan tomorrow is to try the control box from an old working burner (same box as whats on there) and then try the capacitor

Stumped after that. I dont think it can be the connection between the motor and the pump as some suggest (on here and elsewhere) as it can run fine for a day or two or can cut out every time it tries to come on.

Happy to take ideas. A new burner is 'only' £330 and may be easier and cheaper at this rate!

 

[julianf]

Could be loads of things, but id guess at maybe a very slight air ingress that it can run though ok, but, when it turns off for a while, the air floats up (or whatever) and causes a failure on first ignition.

I mean its clutching at straws, and, yes, swapping the whole burner unit out for an identical would be interesting, as that would rule it out.

Used RDB1 burners used to be about £60 on ebay.

 

[reb78]

Could be loads of things, but id guess at maybe a very slight air ingress that it can run though ok, but, when it turns off for a while, the air floats up (or whatever) and causes a failure on first ignition.

I mean its clutching at straws, and, yes, swapping the whole burner unit out for an identical would be interesting, as that would rule it out.

Used RDB1 burners used to be about £60 on ebay.

Thats a good point I would certainly consider a used one. It doesnt have to be new.

I am clutching at straws too TBH. There isnt much more to replace on this one!

It does come off of the same tank connection as the other two boilers and our plumber has suggested as a theory that if two try to come on together do the struggle for fuel and therefore one cuts out. I went out earlier when I knew one had started up and the other was running. The tank feeds into a three port filter and that has two 10mm diameter lines coming off of it. One to this boiler and another to the other two boilers. I dont think it is this but its a fair thought.

 

[Dev]

Is it definitely ‘sparking’? Last time I had trouble with my burner that was the issue - the hissing/crackling of the igniter is distinctive when you know what to listen for.

 

[julianf]

Thats a good point I would certainly consider a used one. It doesnt have to be new.

I am clutching at straws too TBH. There isnt much more to replace on this one!

It does come off of the same tank connection as the other two boilers and our plumber has suggested as a theory that if two try to come on together do the struggle for fuel and therefore one cuts out. I went out earlier when I knew one had started up and the other was running. The tank feeds into a three port filter and that has two 10mm diameter lines coming off of it. One to this boiler and another to the other two boilers. I dont think it is this but its a fair thought.

If youve got a few boilers with the identical burner, just swap the whole burner between them and see if the fault follows the burner or stays at the location.

I mean its probably less than 20 mins work?

 

[reb78]

If youve got a few boilers with the identical burner, just swap the whole burner between them and see if the fault follows the burner or stays at the location.

I mean its probably less than 20 mins work?

I hadnt thought of that. But yes, one is identical...! The other is a fair bit bigger.

 

[reb78]

Is it definitely ‘sparking’? Last time I had trouble with my burner that was the issue - the hissing/crackling of the igniter is distinctive when you know what to listen for.

Yes, it will fire up fine when you are stood by it.

 

[Onoff]

I've had a duff capacitor before.

The most intermittent operation issues were down to the 2 6202 2RS bearings. There's one either end of the motor but I don't think they're shown on the GA.

 

[Onoff]

My trials:

Oil Boiler Locking Out

Typical! ?? A couple of weeks after cleaning and power flushing the CH system then adding inhibitor, the boiler today is periodically locking out. As in you wonder why the place is cold and have to go and press the red reset button on the Riello burner. Only just noticed the problem tonight. - Oi...

forum.buildhub.org.uk

 

[reb78]

I've had a duff capacitor before.

The most intermittent operation issues were down to the 2 6202 2RS bearings. There's one either end of the motor but I don't think they're shown on the GA.

View attachment 426627

What were the symptoms of the capacitor?

Thats interesting as those bearing are CHEAP! (even for a brand). Where abouts are they on the diagram (I am being dumb perhaps and have had wine now)?

 

[reb78]

My trials:

Oil Boiler Locking Out

Typical! ?? A couple of weeks after cleaning and power flushing the CH system then adding inhibitor, the boiler today is periodically locking out. As in you wonder why the place is cold and have to go and press the red reset button on the Riello burner. Only just noticed the problem tonight. - Oi...

forum.buildhub.org.uk

I read this every time I get a lockout! :-)

 

[JOEPRO]

As above, I have a Grant boiler with an RDB1 Riello burner (have three actually.. but one is playing up).

It locks out intermittently. Pattern currently seems to be that it will come on, heat up the cottage to 18C when the stat cuts out and then it wont start. It has either locked at at the end of the last burn or start of the next one. Hard to know which.

So far:
- New nozzle fitted - old one looked fine tbh
- Have checked the boiler setup - pump pressure, flue gases and adjusted according to the manufacturers instructions for the nozzle, burner and boiler unit.
- The pump is about a year old so virtually new
- Boiler baffles all removed, internals cleaned and all sealed properly (its external but did have a leak before the flue from the access plate. Sealing hasn't altered the lockout)
- solenoid replaced
- photocell replaced
- oil flow seems good. Bit of gunk in the line so we disconnected both ends and blew through with a compressor
- tank was replaced last year, empty and clean so shouldnt be residual water or muck in the lines anyway

Plan tomorrow is to try the control box from an old working burner (same box as whats on there) and then try the capacitor

Stumped after that. I dont think it can be the connection between the motor and the pump as some suggest (on here and elsewhere) as it can run fine for a day or two or can cut out every time it tries to come on.

Happy to take ideas. A new burner is 'only' £330 and may be easier and cheaper at this rate!

Is it on a condensing oil boiler or standard boiler?

The reason I ask is the plastic condensate traps on condensing boiler's can give alot of trouble and also cause lockout! Stainless is the way to go for them

 

[Onoff]

What were the symptoms of the capacitor?

Thats interesting as those bearing are CHEAP! (even for a brand). Where abouts are they on the diagram (I am being dumb perhaps and have had wine now)?

Test the capacitor and it reads obviously low.

Just realised I didn't take any photos but it's fairly obvious.

Here's a curveball.....the air intake where the fan is, whip the cover off and check that's not full of fluff as it doesn't take much to jam the fan. 4 crosshead screws. TURN THE POWER OFF to the boiler.

 

[Onoff]

You have to take the fan off. Be real careful. I pulled mine off and bent it somehow. It thereafter had a ting, ting, ting noise so I had to "tweak" it a bit. I've also managed to twist the fan on the shaft so the grub screw isn't on the flat but tight on the shaft. That and strip the hex in the grub screw that holds it on. Must sort that sometime.

You can buy a special removal tool:

Genuine RIELLO Oil Burner Fan Blade & bearing Remover - Boiler Technicians Tool | eBay

Genuine RIELLO Boiler and Burner. This tool makes removing the fan from riello oil burners a simple, easy and easy job to complete. Fan Blade must be removed to work on motor, bearings and to clean all RIELLO burners.

www.ebay.co.uk

 

[Misterg]

and then try the capacitor

I had the capacitor fail on ours - symptom was random non-starts.

New cap fixed it; old one tested low.

 

[reb78]

Is it on a condensing oil boiler or standard boiler?

The reason I ask is the plastic condensate traps on condensing boiler's can give alot of trouble and also cause lockout! Stainless is the way to go for them

Standard.

These are abour 23 yrs old and should still be going strong.

 

[reb78]

Test the capacitor and it reads obviously low.

Just realised I didn't take any photos but it's fairly obvious.

Here's a curveball.....the air intake where the fan is, whip the cover off and check that's not full of fluff as it doesn't take much to jam the fan. 4 crosshead screws. TURN THE POWER OFF to the boiler.

Will do.

How do we test the capacitor? I have had ones on other machines that are obviously gone i.e. look like they have blown up! Would or run at all of the capacitor had gone?

 

[reb78]

I had the capacitor fail on ours - symptom was random non-starts.

New cap fixed it; old one tested low.

Thanks. Same as above. How do I test it?

 

[angellonewolf]

capactor tester to see if its giving the right value as stated on the capactor

or as most are so cheap just change it

 

[reb78]

capactor tester to see if its giving the right value as stated on the capactor

or as most are so cheap just change it

I have a spare - its second hand but rhought to be good (whole beleived to be working burner but not setup for this boiler otherwise would.bung it in)