Motor running but not firing

Wearb · 23-01-2013 12:43pm #1

Can someone advise me please? An a RDB 2.2 burner mostly starts ok, but every now and then (some times after running ok for lots of days) the motor runs, but does not fire up. By the time I get to have a look, it has started working ok again. It does not lock out either and will happily stay running without firing. I thought that in circumstances like this that it should lockout after about 20 seconds or so. Every time I go to look at it, it is running ok, so I don't know where to look for fault. The pump pressure is OK and when burner runs it runs and heats perfectly.

Any ideas please? Should it lockout under those circumstances?

Wearb · 23-01-2013 12:50pm

BTW, just in case this is of any use to anybody; while recently fault finding on a grant 50/70 modular boiler, I discovered that the fault was that when the system got hot one of the HT leads (which was close to the electronic eye was expanding and covering the eye. When I unplugged the wire and replaced it after rotating it 180 degrees (so that the curved part was now facing away from the eye) it ran perfectly and 2 months later is still going fine.
Maybe something to watch out for. Might help someone.

To better explain: The wire was travelling in a curve from the transformer to the electrodes. When heated the wire lengthened (or softened) slightly, either way it allowed the curve to move out to obstruct the photocell.

Billy Bunting · 23-01-2013 1:25pm

Wearb wrote: »

the motor runs, but does not fire up. ?

Photocell.

Wearb · 23-01-2013 4:11pm

Billy Bunting wrote: »

Photocell.

Thanks for reply. Can a photo cell give intermittent trouble, i.e. work OK for days and then not work once or twice and then work OK again? Also can motor stay running without lock-out on a photocell fault? Anyway it will be an easy replacement to try.

Billy Bunting · 23-01-2013 5:11pm

The RDB photocell does have an issue that on occasions it will signal that it is seeing a flame its not usually intermitent but its quite common, when its persistent, if you disconnect it from the control box, run the burner, once ignition is established quickly reconnect the photocell, it will run until stat satisfied, that will normally prove the point and you can order the part.

Wearb · 23-01-2013 5:36pm

Billy Bunting wrote: »

The RDB photocell does have an issue that on occasions it will signal that it is seeing a flame its not usually intermitent but its quite common, when its persistent, if you disconnect it from the control box, run the burner, once ignition is established quickly reconnect the photocell, it will run until stat satisfied, that will normally prove the point and you can order the part.

If I can get the fault to replicate itself when I am present, then I will try that. I am still worried that it might be control box. I would expect a lockout on a fault such as you describe? Does the pump valve stay closed to prevent the nozzel spraying oil all over the combustion chamber, because the motor has continued to run without firing. Sorry for so many questions, but I am having trouble understanding the exact sequence of events to be expected with a photocell fault. Especially when the motor continues to run.

Billy Bunting · 23-01-2013 5:49pm

Solenoid valve isn't opened. This has been a fault discused here in the past. You sound like a person who does a bit on burner, a photocell change for €20 and see if the fault reacures, if it does then you have a spare photocell.

Wearb · 23-01-2013 6:07pm

Billy Bunting wrote: »

Solenoid valve isn't opened. This has been a fault discused here in the past. You sound like a person who does a bit on burner, a photocell change for €20 and see if the fault reacures, if it does then you have a spare photocell.

Thanks. I will do that. I have a photocell on an old spare burner that I rebuilt and keep for spares or emergency replacement.
I amazed that Riello haven't changed the control box set-up to lockout the burner on such a fault and not have the pump churning away under pressure. Cant be good for the pump.
Thanks again. I will post back eventually. I may leave it to see if the problem becomes more persistent. As it stands, I could make replacement and not know for over a week if that was the cause.

DGOBS · 23-01-2013 6:23pm

A faulty solenoid can also cause this constant pre-purge, as can the control box, and PE cell as stated above.

I have had this several times as a control box fault (dry solder??), especially when so intermittent

jimf · 23-01-2013 6:55pm

another but unlikely intermittent break down of voltage from motor to control box 53v white wire

Wearb · 23-01-2013 8:23pm

DGOBS wrote: »

A faulty solenoid can also cause this constant pre-purge, as can the control box, and PE cell as stated above.

I have had this several times as a control box fault (dry solder??), especially when so intermittent

Thanks. I will go one step at a time starting with the cheapest part. Fingers crossed that I don't eventually replace the control box and still have a problem

Wearb · 23-01-2013 8:25pm

jimf wrote: »

another but unlikely intermittent break down of voltage from motor to control box 53v white wire

Thanks. It just gets better all the time.
I did get correct voltage on the white wire, but then it was running OK at THAT time.

shane0007 · 23-01-2013 9:33pm

If the fault happens, disconnect the photocell cable from the control box. If it goes to lock out, replace the photocell. If it continues to run, replace the coil. If it still continues to run, replace the control box.
The reason it does this is the control box knows it is getting a false signal from the photocell. At that stage of the ignition process, the control box is looking for darkness, i.e. no flame. If it does not confirm this, then it will keep the motor running, i.e. the fan, to blow out a flame that maybe established. It is a deliberate safety feature and not something that needs to be changed by Riello!

Wearb · 23-01-2013 10:06pm

shane0007 wrote: »

If the fault happens, disconnect the photocell cable from the control box. If it goes to lock out, replace the photocell. If it continues to run, replace the coil. If it still continues to run, replace the control box.
The reason it does this is the control box knows it is getting a false signal from the photocell. At that stage of the ignition process, the control box is looking for darkness, i.e. no flame. If it does not confirm this, then it will keep the motor running, i.e. the fan, to blow out a flame that maybe established. It is a deliberate safety feature and not something that needs to be changed by Riello!

Thanks. I will try that.
I don't understand how the control box knows its getting a false photocell reading, but that is for another day. I will try and get to this boiler when it is in one of its not firing humours.

shane0007 · 23-01-2013 10:11pm

It is measuring resistance via lux. It will depend on the fault of the photocell that determines the reaction of the control box. Some photocell faults will result the control box putting the burner into lock out.

Wearb · 24-01-2013 12:43am

shane0007 wrote: »

It is measuring resistance via lux. It will depend on the fault of the photocell that determines the reaction of the control box. Some photocell faults will result the control box putting the burner into lock out.

Thanks for that explanation. I didn't know that the photocell sent variable signals to control box. I thought it was either seeing light or not. Knowing that it returns results more complicated than on or off will be helpful in the future. Thanks for going to the trouble of explaining that to me.

Wearb · 29-01-2013 1:31pm

I have changed photocell, coil, control box and now pump. I don't expect the pump to solve the problem, but will see.

I still haven't gotten to the system when it has been faulty. Every time I called it was working. I would like to get a voltage reading on the white wire while it is misfiring.

Exact symptoms are: starts, fires up with flame established, about 10 seconds later flame goes out but motor keeps running, after about 10 seconds flame re-establishes and the whole cycle continues (until a few minutes before I arrive to check it, by which time it is running perfectly)

It has been most (but not always) problematic in the early morning, which leads me to believe it may be an air fuel mixture problem, but I have set it up according to the manual (used analyser). If still giving trouble, I will try it with a hollow nozzle (solid recommended) and set it up for that. After that I am out of ideas.
Would REALLY appreciate any suggestions.

jimf · 29-01-2013 1:40pm

what boiler is this fitted to is it balanced flued any chance of flugas recycling being the cause

Billy Bunting · 29-01-2013 1:50pm

Wearb wrote: »

Can someone advise me please? An a RDB 2.2 burner mostly starts ok, but every now and then (some times after running ok for lots of days) the motor runs, but does not fire up.

You are now changing the story......

Wearb wrote: »

Exact symptoms are: starts, fires up with flame established, about 10 seconds later flame goes out but motor keeps running, after about 10 seconds flame re-establishes and the whole cycle continues (until a few minutes before I arrive to check it, by which time it is running perfectly)

I agree with Jim, a little more presice information would help......

Wearb · 29-01-2013 2:03pm

jimf wrote: »

what boiler is this fitted to is it balanced flued any chance of flugas recycling being the cause

Balanced flue. Warmflow 70/90 boiler. Nothing changed in years that might cause this to be Flue gas recycling.

jimf · 29-01-2013 2:06pm

wearb

your last post could possibly indicate an overaired burner or fluegas recycling but if set up with fga and your happy with readings then it
should not be overaired

post your fga readings and pump pressure

jimf · 29-01-2013 2:09pm

Wearb wrote: »

Balanced flue. Warmflow 70/90 boiler. Nothing changed in years that might cause this to be Flue gas recycling.

again not enough info is it boilerhouse or what

Billy Bunting · 29-01-2013 2:09pm

Module, Utility or Boilerhouse model ?

Wearb · 29-01-2013 2:18pm

Billy Bunting wrote: »

Module, Utility or Boilerhouse model ?[/Quote

Not have readings to hand. But I know that pump at 8 bar and got best overall fg readings at 11.7 co2. Boiler house model. Good air vent on boiler house.

Excuse slow reply. I am using my tiny buttoned phone

jimf · 29-01-2013 2:36pm

Wearb wrote: »

Billy Bunting wrote: »

Module, Utility or Boilerhouse model ?[/Quote

Not have readings to hand. But I know that pump at 8 bar and got best overall fg readings at 11.7 co2. Boiler house model. Good air vent on boiler house.

Excuse slow reply. I am using my tiny buttoned phone

i know this might sound extreme but do you have a PROVEN spare burner to exchange if same problem persists then you know for sure its not a burner issue
and you have to start looking elsewhere to be honest you nearly have a new burner fitted already with the earlier mentioned parts

its jobs like this that make you sorry you didnt bring the sledge

Billy Bunting · 29-01-2013 3:27pm

Are you using the snorkle on the flue ??

Wearb · 29-01-2013 3:28pm

jimf wrote: »

Wearb wrote: »

i know this might sound extreme but do you have a PROVEN spare burner to exchange if same problem persists then you know for sure its not a burner issue
and you have to start looking elsewhere to be honest you nearly have a new burner fitted already with the earlier mentioned parts

its jobs like this that make you sorry you didnt bring the sledge

All those parts came off a working burner. If still giving trouble after pump change, I will put them all back on my burner and fit it to the system. It just might be a faulty feed from motor to control box.

What do you think of trying a hollow nozzle before I do that?

I really really would like to take a sledge to it. Especially if the pump solves the problem, because the owner was insisting that it was the pump from the start. He was basing this assumption on a neighbour having had a boiler problem that was fixed by a pump replacement. If pump solves it, my name is kaput there. Still, my first responsibility is to fix it and try and mend fences afterwards.

(in case that last statement (neighbours pump) leads you to suspect an oil contamination problem, the last delivery was 7 months ago and tank is still half full. Filters spotless, no water showing on paste)

.jacksparrow. · 29-01-2013 3:33pm

Wearb wrote: »

jimf wrote: »

All those parts came off a working burner. If still giving trouble after pump change, I will put them all back on my burner and fit it to the system. It just might be a faulty feed from motor to control box.

What do you think of trying a hollow nozzle before I do that?

I really really would like to take a sledge to it. Especially if the pump solves the problem, because the owner was insisting that it was the pump from the start. He was basing this assumption on a neighbour having had a boiler problem that was fixed by a pump replacement. If pump solves it, my name is kaput there. Still, my first responsibility is to fix it and try and mend fences afterwards.

(in case that last statement (neighbours pump) leads you to suspect an oil contamination problem, the last delivery was 7 months ago and tank is still half full. Filters spotless, no water showing on paste)

Ah the usual,the owner already has it solved so what's the need for you?that does my head in when they try tell you what's wrong before you even have a look.

Have you changed the control box?

Wearb · 29-01-2013 3:48pm

Billy Bunting wrote: »

Are you using the snorkel on the flue ??

SORRY the above question just made me realise that I previously answered incorrectly about it being a balanced flue (I must be going demented over it) It is a low level flue with air being drawn in through an air vent on the opposite side of the boiler house.

Also, perhaps I should mention that original setting on air adjuster was 6.5 when I first called and I have now set at 4.5 after using smoke pump and analyser. I didn't use analyser until using the smoke pump, but can only assume that there was way too much air originally, though it ran for 10 year at that setting. I had to turn the air down to almost 4 before I got staining on the smoke filter paper.
I did open the air chamber to check fan and proper functioning of air adjuster. One time found a feather in there that was causing all sorts of intermittent problems, but that was on a different boiler.

Wearb · 29-01-2013 3:55pm

.jacksparrow. wrote: »

Wearb wrote: »

Ah the usual,the owner already has it solved so what's the need for you?that does my head in when they try tell you what's wrong before you even have a look.

Have you changed the control box?

Yep. Motor and electrodes are all that have not been replaced now.

.jacksparrow. · 29-01-2013 3:56pm

Wearb wrote: »

.jacksparrow. wrote: »

Yep. Motor and electrodes are all that have not been replaced now.

Have you checked inside the boiler?could be getting blowback.

Wearb · 29-01-2013 4:01pm

.jacksparrow. wrote: »

Wearb wrote: »

Have you checked inside the boiler?could be getting blowback.

Yes. It was almost spotless, though not serviced for many years. Perhaps so clean as a result of it getting way too much air for years.

jimf · 29-01-2013 4:30pm

Wearb wrote: »

.jacksparrow. wrote: »

Yes. It was almost spotless, though not serviced for many years. Perhaps so clean as a result of it getting way too much air for years.

be careful overairing is one of the main causes of high co

what area are u operating from good spread of lads posting here maybe your living close to someone who might be willing to help you on site

maybe pump but ive never come across one acting this way when you have your gauge fitted is pump giving a good steady 8 bar reading with no fluctuations up or down any possibility of air being drawn in via perforated fuel line only guessing now myself

jimf · 29-01-2013 4:52pm

sorry but when i say im only guessing now myself i didnt mean to insinuate you are only guessing it looked bad when i read back my own post

Wearb · 29-01-2013 4:55pm

jimf wrote: »

Wearb wrote: »

be careful overairing is one of the main causes of high co

what area are u operating from good spread of lads posting here maybe your living close to someone who might be willing to help you on site

maybe pump but ive never come across one acting this way when you have your gauge fitted is pump giving a good steady 8 bar reading with no fluctuations up or down any possibility of air being drawn in via perforated fuel line only guessing now myself

I have the flue gasses working within recommended parameters, but I must recheck them to be sure to be sure. I need to be able to fix this myself. I know local lads who will help if I fail to fix it, but I will not call on them until I have exhausted all options, which may eventually mean fitting a working burner that I have been taking parts off. I am sure you understand this.
Yes nice steady 8 bar on pump. No sign of any moisture on fuel line. Bottom of oil tank is at least 15 inches above boiler, so any air leaks would probably result in oil leak when not running.

Wearb · 29-01-2013 5:06pm

jimf wrote: »

sorry but when i say im only guessing now myself i didnt mean to insinuate you are only guessing it looked bad when i read back my own post

I didn't take it up wrongly. I know you are all trying your best to help me.

I will post everything I did when I get it sorted, even if I haven't identified the exact problem.

jimf · 29-01-2013 5:13pm

at least you had the balls to come on and ask for help all the lads on here are very helpful and will never judge you only help where possible and believe me there are some brilliant tips to be picked up if you go back over old posts when you have time and have this problem put to bed

Billy Bunting · 29-01-2013 5:16pm

Wearb wrote: »

I didn't take it up wrongly. I know you are all trying your best to help me.

I will post everything I did when I get it sorted, even if I haven't identified the exact problem.

If you have a few pics of the boiler / house, vents / flue it would help us in seeing just whats in front of you.

Wearb · 29-01-2013 5:28pm

Only have a few photos. Will take other ones next time I call.

Dtp79 · 29-01-2013 5:49pm

Wearb wrote: »

Only have a few photos. Will take other ones next time I call.

Did you check the capacitor? I had a similar problem before and it was a temperamental capacitor

Wearb · 29-01-2013 8:46pm

Dtp79 wrote: »

Did you check the capacitor? I had a similar problem before and it was a temperamental capacitor

Thanks for input. Don't think it can be a capacitor problem, because there has never been a problem with motor starting.

Dtp79 · 29-01-2013 8:56pm

Wearb wrote: »

Thanks for input. Don't think it can be a capacitor problem, because there has never been a problem with motor starting.

That's what I thought when it happened to me. Didn't make sense back then and still dosent make sense but it did the trick!!

Wearb · 29-01-2013 9:27pm

Dtp79 wrote: »

That's what I thought when it happened to me. Didn't make sense back then and still dosent make sense but it did the trick!!

Well you just never know. I am almost willing to try some pagan ritual at this stage.

Dtp79 · 29-01-2013 9:43pm

Wearb wrote: »

Well you just never know. I am almost willing to try some pagan ritual at this stage.

Ye I tried the ritual before the capacitor and it didn't work

Wearb · 30-01-2013 1:59pm

I think I have gotten to the bottom of my problem. I should have taken a hammer to the customer, but I need to keep him and perhaps get recommendations from him. Time will tell if this has sorted it.

Started this morning to dismantle the boiler (I decided to start from scratch again) Taking off the top boiler cover, I noticed a home made cover gasket made from fibre glass. It was a good job as such jobs goes. The original was starting to fail but was OK and I had decided to leave its replacement to the next service. I had told the customer this on my first visit when I checked everything and expected everything to be the same as I left it.

I removed this improvised gasket and found most of the old one down on top of the top baffle plates. I asked him why he didn't mention this "handy-work" to me and he said that he didn't think that doing what he did would make any difference to the burner as he had been only fixing the gasket on the boiler. At this stage I was almost splitting my tongue. But calmly explained to him the problems his action had caused. Anyway I have fixed up everything in there and hopefully that will be the cure.
I suppose if I had run a second analyser test I might have discovered this, but I thought after sorting that out first time that nothing would have changed there. You live and learn.

Thank you all for your help. It helped me maintain confidence (which was shaken) in my work. I will post here if this has not sorted out the problem.

.jacksparrow. · 30-01-2013 2:28pm

Wearb wrote: »

I think I have gotten to the bottom of my problem. I should have taken a hammer to the customer, but I need to keep him and perhaps get recommendations from him. Time will tell if this has sorted it.

Started this morning to dismantle the boiler (I decided to start from scratch again) Taking off the top boiler cover, I noticed a home made cover gasket made from fibre glass. It was a good job as such jobs goes. The original was starting to fail but was OK and I had decided to leave its replacement to the next service. I had told the customer this on my first visit when I checked everything and expected everything to be the same as I left it.

I removed this improvised gasket and found most of the old one down on top of the top baffle plates. I asked him why he didn't mention this "handy-work" to me and he said that he didn't think that doing what he did would make any difference to the burner as he had been only fixing the gasket on the boiler. At this stage I was almost splitting my tongue. But calmly explained to him the problems his action had caused. Anyway I have fixed up everything in there and hopefully that will be the cure.
I suppose if I had run a second analyser test I might have discovered this, but I thought after sorting that out first time that nothing would have changed there. You live and learn.

Thank you all for your help. It helped me maintain confidence (which was shaken) in my work. I will post here if this has not sorted out the problem.

So it was blowback?

Wearb · 30-01-2013 2:44pm

.jacksparrow. wrote: »

So it was blowback?

Seems like it was, but oh so inconsistent. Never misfired in my presence.

.jacksparrow. · 30-01-2013 3:39pm

Wearb wrote: »

Seems like it was, but oh so inconsistent. Never misfired in my presence.

Glad you got it sorted,I hate those ones that have you doubting yourself,but once you keep at it it pays off.

One thing I learned is never believe or take for granted something the owner might or might not have done.

Have you seen the previous page?all your quotes are saying I wrote them and vice versa.

Anyway hopefully that's it but as you know you can never be sure,all that is left is the bill!

jimf · 30-01-2013 3:52pm

dont you just love some customers

well done at least now you know your cut out for the job of making all that easy money i wish

Wearb · 30-01-2013 4:44pm

.jacksparrow. wrote: »

Glad you got it sorted,I hate those ones that have you doubting yourself,but once you keep at it it pays off.

One thing I learned is never believe or take for granted something the owner might or might not have done.

Have you seen the previous page?all your quotes are saying I wrote them and vice versa.

Anyway hopefully that's it but as you know you can never be sure,all that is left is the bill!

How do you charge for such a job. Certainly can't charge my regular rates. But still it's better to be earning something.

.jacksparrow. · 30-01-2013 4:51pm

Wearb wrote: »

How do you charge for such a job. Certainly can't charge my regular rates. But still it's better to be earning something.

Can you take back the parts you changed?

Motor running but not firing

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