Riello RDB burner lockout (Firebird combi)

[Stevie187]

Hi all,

The burner keeps locking out on my boiler with increasing frequency to the point it can be every few minutes.

So I thought it was locking out when working but it's seems it gets up to temperature shuts off and this can happen the first time or any number of times.

Quiet buzzing
Louder buzzing
Click constant red light lockout

Reset it goes through the procedure I hear the motor spin then the big whoosh and back to normal, until the next time it starts up again sometimes it whooshes straight away no buzzing, sometimes it buzzes then starts, most of the time now it buzzes then locks out no spinning up of motor.

Cad cell out cleaned tested resistance seems within specs but have ordered new one anyway as the shroud is cracked near the sensor.

Tested resistance on solenoid and got about 30ohms I think across different combinations of the leads.

Could it be the capacitor? I haven't got the means to test that but heard it can cause similar faults. I wish I understood the noises and what they translated to, I think the loud buzzing sounds like HT perhaps the electrodes getting energised but the boiler then not firing? I don't know any help greatly appreciated.

Thanks
Steve

 

[SJB060685]

It could be the capacitor yes. A faulty cap can cause a lag in start or noises that you hear and then start, it can also cause the motor to stall. I would whip pump off and check for tight spots, also check motor shaft for tight spots, bearings could be bad. Also like I said check cap value, should be 70% or more of original value. I must add if it's the motor bearings or cap you could burn motor out while constantly trying to run.

 

[Stevie187]

Thank you so much for the reply thing is it can run fine for hours then refuse to spin up. I have been watching some YouTube videos on the Riello boiler I understand better now the cycle. So definitely sometimes the motor fails to run and when it fails it locks out. Looking at the service history of the boiler it had a new pump about a year ago. but I guess neither here nor there. I ordered cell off Amazon but the caps I can't get prime delivery on and seem expensive for a cap are their local stores I can get them?
[automerge]1575664013[/automerge]
Just had another look at Amazon and I can get some capacitors for nominal amounts, are they start or run capacitors?
[automerge]1575664138[/automerge]
I'm thinking start...

 

[SimonG]

A decent oil engineer will sort it no problem.

After all a decent engineer isn't just for christmas.

 

[SJB060685]

I totally agree SimonG, a good engineer is for life. However the OP sounds like he has a basic understanding, which is more than I can say for some who actually work on these things and this is basic day one stuff. From what he's said and like I said above it's most likely the pump sticking, motor bearings seizing or the cap and it will only take 5-10 minutes to check. Having said that it is worth having a good engineer at hand so when the not so basic happens you aren't left scratching your head lol

 

[Stevie187]

Thanks for that Simon! If I can swap a capacitor out and it fixes the problem then I will take that all day long! Plus I will struggle to get one out tomorrow.

Can I go up in value to a 5uf cap they seem in more Abundance than 4,5s I think they are used on washing machines. I'm pretty sure with starter caps you can have a 10% difference.

 

[SimonG]

I totally agree SimonG, a good engineer is for life. However the OP sounds like he has a basic understanding, which is more than I can say for some who actually work on these things and this is basic day one stuff. From what he's said and like I said above it's most likely the pump sticking, motor bearings seizing or the cap and it will only take 5-10 minutes to check. Having said that it is worth having a good engineer at hand so when the not so basic happens you aren't left scratching your head lol

Sometimes a basic understanding can be dangerous. After all it's a combustion appliance.

 

[SJB060685]

That is true. My old man once said a little understanding is more dangerous than no understanding.

 

[Stevie187]

You are very true a little understanding is a lot more dangerous. I'm sensible though if it's not the cap or other easily changeable device I will leave it to a pro. I would never mess with anything that has the potential to mess up the afr ratio or something like that and rich it out soot up the flues and gas my family out or lean it out and melt the boiler and blow them up! I have a good understanding of physics/electronics and know my own limits.

 

[Best]

Hello Steve,
Afraid I have to agree with the above posts and say it could be a number of things and really should have a full service including a check on condition of the mechanical parts.
Replacing a capacitor with identical type for anyone competent enough is perhaps worth a try.
But there might be something else causing that to fail, or some other part altogether. The motor or oil pump but that requires analyser set up.

 

[SimonG]

You are very true a little understanding is a lot more dangerous. I'm sensible though if it's not the cap or other easily changeable device I will leave it to a pro. I would never mess with anything that has the potential to mess up the afr ratio or something like that and rich it out soot up the flues and gas my family out or lean it out and melt the boiler and blow them up! I have a good understanding of physics/electronics and know my own limits.

Doesn't matter what understanding you have. I'd you don't do it for a living then leave it alone.

 

[Stevie187]

Doesn't matter what understanding you have. I'd you don't do it for a living then leave it alone.

So you wouldn't advise an end user to change a capacitor?

 

[SJB060685]

We could help you locate the offending part but once that part has been changed then the burner needs to be set up properly, using a flue gas analyser etc. That is to ensure both running efficiently but by no means least safely. Remember what I've said, call an engineer out and tell him the above.

Edit as only just seen above post. Do not increase the capacitance value of cap. This can cause the motor winding to burn out, amongst other problems

 

[Stevie187]

No I appreciate that but there's no way changing a faulty capacitor is going to have changed the combustion to the amount that the boiler would need re setting up.

 

[SimonG]

I'm not trying to be patronising or clever. At the end of the day it's a combustion appliance, if not looked after properly they can kill.

 

[Stevie187]

Well we agree on something