Riello cold start issues

mikeavery86

Hello all, I have a buderus g115 with riello 40 f3 that has a issue cold starting. I've changed the filter on pump, main filter, checked oil pressure, changed the nozzle, photocell, solenoid and valve, checked for contaminated oil all with no avail. On cold starts it takes numerous tries to get going. Once warm it runs fine. Any ideas?

STEVEusaPA

Is it air in the line? Only takes a slight vacuum leak. Riello's can be tricky to power bleed without either using a deviator switch or the flashlight trick.
Gravity/Lift? One pipe/two pipe?

Do you have a pump manifold with clear tubing you can attach and watch the fuel line for air?

Tom_133

I bet its the electrodes. I had the same thing at my place, and instead of changing any parts I called Riello, he told me electrodes, I said "bologna" he said mine were not getting hot enough. So I changed them and he was dead on.

mikeavery86

I have a tiger loop which should take out any air, all lines are tight and no leaks. Maybe I'll try the electrodes although it does sound strange. Anyone know the gap or settings for the new electrode installation?

HVACNUT

I dont think I've ever had to gap or adjust F3 electrodes.
If it's the OEM burner for the G115, factory air setting is usually too high but you need an analyzer to check that.

GW

4mm up, 4 mm spread and 1 mm forward

You sure it’s not draft? Too much and you won’t light. I would play with the barometric and put my hand on the burner gate to see if it helps kick it in

Also maybe try turning the pressure up a tad if you are really stuck. New burners are 175 or so. Older burners are 150 or so. Jack it up and drop the nozzle accordingly

Vac is good? Bypass installed? You have oil lol

If you’re still stumped, and if space allows, turn the burner sideways and flip the swifch, make sure it’s doing stuff. Sparking, try a new nozzle

mercedes

Hello

Maybe this will help page 11 for electrode spec.
https://inspectapedia.com/heat/Riello-40-Series-Oil-Burner-Manual.pdf

GW

Humph I guess incorrectly

2 to 2 -/2 forward wow my memory is really off

mikeavery86

Covering the air gate helps it start but it was running fine until recently, that's what has me stumped. Draft is good and full tank of oil. I dont have anything to test vacuum but pressure was preset at 150 so I bumped up to 160 and not any better. Not sure what the bypass is and it has a new nozzle.

SuperTech

I have had two problem Riello burners on Buderus boilers. Everything clean from the filter to the heat exchanger. One is a single pipe, the other a two pipe. Both burning clean and confirmed by combustion analysis. -.046" of draft in one and -.036" in the other. I don't remember over fire readings but they were both slightly positive. Both units will run fine for days, weeks even. Then the Riello locks out.
I was lucky enough to have the Buderus manual on site, but that just says see the Riello manual. Which was missing.

I'm wondering now if it could be the electrodes ...

STEVEusaPA

I guess we’ll need a full combustion report including over fire, breech numbers, air gate and head settings, smoke. But if you put your hand over the air gate and it fired up, then air/draft would be a good start.
I’ve only replaced electrodes once, and that was because I over tightened the screw and cracked them. Years ago in a class, the instructor took the electrodes, pointed them away from each other, about an inch and a half apart and the spark still jumped the gap. So unless the are cracked, I would say it is the least likely reason.
Also if you ever looked at the troubleshooting card, seems like 99% of the diagnostics end in "change the control box", so maybe check all wires/connections on the base plate. If it still does it, change the box. Unfortunately in America, Riello won’t let us have the troubleshooting tool that hooks to all components to check them.
One more thing, the combustion head has an orientation to it. If you removed the 2 screws on the head to change the nozzle (not the right way, btw) and flip it over, the hole doesn’t line up with the nozzle.

STEVEusaPA

SuperTech said:

I have had two problem Riello burners on Buderus boilers. Everything clean from the filter to the heat exchanger. One is a single pipe, the other a two pipe. Both burning clean and confirmed by combustion analysis. -.046" of draft in one and -.036" in the other. I don't remember over fire readings but they were both slightly positive. Both units will run fine for days, weeks even. Then the Riello locks out.

I was lucky enough to have the Buderus manual on site, but that just says see the Riello manual. Which was missing.



I'm wondering now if it could be the electrodes ...

You remember both breech draft readings but not the overfire? Those breech readings may be too high. Overfire draft is most important.
For me, if it’s not a component, and the oil line is fine, it’s usually air/draft.

mikeavery86

Ok I'm going to look it all over again and make sure I didn't miss anything by mistake. I appreciate all the input and quick responses. I'll be back with an update in the morning. Thanks again

SuperTech

I only remember the one I saw today. +.143"-+.156". I set the barometric dampers on both boilers. The larger one always had lower draft.
I'm not completely sure what the optimal over fire draft should be. That's what I was looking in the Buderus manual for. No cell service at this house so looking online wasn't an option. I was taught that the over fire should always be slightly positive, but I'm sure there are specific settings. What do you usually set them to? CO2 and O2 were right around 5-5.5% O2 and 11.50-12% CO2.

GW

If you install a tiger you need to install the teensy bypass plug that comes with the Riello. You stick it in the return port, with a teensy Allen wrench

SuperTech

> @GW said:
> If you install a tiger you need to install the teensy bypass plug that comes with the Riello. You stick it in the return port, with a teensy Allen wrench

I'd prefer to see the tiger loop ultra on all Riello burners. Only one of the two I'm having trouble with have a Garber filter. I'd actually like to see all oil equipment have the Ultra, but it's hard to convince a customer that it offers benefits unless they are having issues.
Gary what is your thoughts on over fire settings on Riello/Buderus equipment?

STEVEusaPA

The manual shows the opposite of what I know for other boiler/burner combos. Says 0 to -.03 at the breech, and 0 to slightly positive, based on breech draft (chimney fired).
https://www.bosch-climate.us/files/2011_08_26_Riello_Burners_Specification_on_Buderus_G115_US_US.pdf

Tom_133

Guys,

I really think he has the same problem I did. Mine started acting up in the spring, I was getting warm days it would be off all day then it would try to fire cold, it would and kick, puke, slap the barometric open and close and clang, smoke then it would get rolling and be fine all night as it got cold it started more. I was convinced I needed a tiger loop, I reasoned "its 10 years running fine, now I have a leak?" Thats why I called Riello.
Super glad I did or I would have done just what he did. The tips of my electrodes were not even that bad, the only thing I noticed with my electrodes was they were much longer than normal ones on the shelf, I had to special order them. I have the same setup as this guy maybe his are much longer as well.

Just saying, it stumped me and I DID NOT agree with it, and it fixed it perfectly. Its also the only thing he hasn't tried.

SuperTech

I'm going to see if I can get back over to the customer I was at yesterday to replace the electrodes. I'm pretty sure I've heard about this issue before and I believe I made a mistake when I replaced the control. I'll report back with results.

STEVEusaPA

Tom_133 said:

Guys,

I really think he has the same problem I did. Mine started acting up in the spring, I was getting warm days it would be off all day then it would try to fire cold, it would and kick, puke, slap the barometric open and close and clang, smoke then it would get rolling and be fine all night as it got cold it started more. I was convinced I needed a tiger loop, I reasoned "its 10 years running fine, now I have a leak?" Thats why I called Riello.
Super glad I did or I would have done just what he did. The tips of my electrodes were not even that bad, the only thing I noticed with my electrodes was they were much longer than normal ones on the shelf, I had to special order them. I have the same setup as this guy maybe his are much longer as well.

Just saying, it stumped me and I DID NOT agree with it, and it fixed it perfectly. Its also the only thing he hasn't tried.

Could've fixed your issue inadvertently as you opened every thing up and put it back together, possible affecting another component, setting or wiring.
Considering the control only sparks for something like 3/10 of a second, I don't see how the electrodes, and the electrodes alone, would've been responsible for the cold start issue you experienced, or the fix for the issue.
Hey I could be wrong...and it is 'fixed'...

STEVEusaPA

SuperTech said:

I'm going to see if I can get back over to the customer I was at yesterday to replace the electrodes. I'm pretty sure I've heard about this issue before and I believe I made a mistake when I replaced the control. I'll report back with results.

I'd wait for the call back, unless you are putting the old control back on.

Tom_133

STEVEusaPA,

Right there with you, I don't know exactly why it fixed it.

Riello mentioned the electrodes not getting proper spark and that why it was coughing and puking. Its a Riello problem, for whatever reason. Lets hope it works for this guy too.

GW

I try for meg o2 or o3. Anything higher it’s gonna get fussy

mikeavery86

Ok so follow up, I pulled everything apart to double check the electrodes which were gapped within spec. I decided to put a new valve stem in because the nozzle seemed to have excessive fuel on it like the valve wasn't closing properly. Checked all fittings to make sure no leaks and manually bled the air even though it has the tiger loop using the flashlight to photocell trick. Fired it up this morning and fired right up first try and stayed running! Going to do another cold start tonight to see if it's still good. Thinking the valve stem was defective and letting fuel out and displacing with air causing cold start issue. Not sure if there is a proper orientation when installing the valve stem but I installed with the inlet holes facing up and down instead of the original side to side. I appreciate everyone's input here. Also electode tips were different lengths but adjusted properly, not sure how these are replaced, only as a pair or maybe by single. Should have taken a picture.

SuperTech

Unfortunately for me I was only able to get the short electrodes, like the ones that I have in the Riello rescue box. After I put the long electrodes back on when I went to restart it and it just seemed like the burner motor would run forever without the burner lighting or locking out. I eventually got it to fire and every time I tested it after that it would fire up within twenty seconds.
My plan is to try to obtain the long electrodes today so hopefully I can see if that takes care of this issue.

Grallert

What GW said.
Also maybe try turning the pressure up a tad if you are really stuck. New burners are 175 or so. Older burners are 150 or so. Jack it up and drop the nozzle accordingly
Of course this would be done with an analyzer in place. Because that boiler has no Fiber combustion chamber it will struggle on a truly cold start meaning no indirect water heater. You mentioned that you could at one point get it to start by partially cover the air shutter. That gave the chamber a chance to warm a bit. Sometime on a truly cold start the chamber will condence adding moisture to the fire and extinguishing the flame.
Try Increasing the pump pressure a bit, again with an analyzer in place.

HVACNUT

> @SuperTech said:
> I eventually got it to fire and every time I tested it after that it would fire up within twenty seconds.

Theres a 10 second pre purge and a 5 second trial for ignition. If your fires at 20 seconds, theres other issues besides the air and turbulator adjustments (hint, hint).

dav

If it is a riello f3 and a buderus g115 ws4 or g115 /28 . Set the pump pressure to 190 use a .65 60 nozzle. Make sure the blast tube insertion depth. This will burn at .90 you. Turbulator setting at 3. Air setting at about 5.25 +/-
Chimney vent.
Slightly overtired boiler.
It WILL save you oil.
All of my test are done with combustion analyzer.
Co2 at 13%
O2 at 4%
0 smoke
Co at 24 ppm
Turning up pressure stopped poor light off.
Electrode setting at 1/4 inch for 60 Hertz system

Dave

dav

Blast tube insertion depth 6 inches.

STEVEusaPA

Air tube, not blast tube.

dav

Also, further, I do not believe the flame is ever extinguished but outside forces, for example draft or condensation. When the pump pressure is.lower, the flame is not a bright and the cad cell does not see it properly, so the control shuts the oil supply down. Just my observations.
I, also performed tests on this boiler, and measured oil used. Upfiring this boiler does use less oil.
Dave

EBEBRATT-Ed

Replace it with a Carlin or a Beckett.

DunSpannerin

You guys get your riello burner issues sorted?
Here's my take on Riello RB2.2 failing to fire/failing to continue firing when cold. Control box then PE sensor replaced. Unit removed from boiler. Wire L1, N to prepared power cord, turn on at switch. Burner does 8-10 prep, fires momentarily, then drops out. disconnect PE at plug on control box, switch on again, burner fires for around 5 secs (which is correct operation), burner drops out again due to PE disconnected (correct operation). Remove PE cell from burner housing, leave plug at other end disconnected, face LDR to light. Turn on power switch again, wait for initial firing, then plug PE plug back onto control box, all the while facing the LDR (light dependent resistor cell) at the light. Unit now continues to run.
Put everything back where it belongs, remove control box cover, point hot air gun at 80°C into board area, warm up, also warm up PE cell. Unit now fires as it should.
Fault, IMO is thermal drift from ancient circuit board, old carbon resistors, wire jumpers, ancient, probably 1960's. (not one IC).
Remedy: Dump unit, buy better quality.