Riello 40 F5. Flame

Oilfool

I just serviced my burner last night and have been using the same nozzle and electrodes for years. I haven't done an efficiency test yet or verified pump pressure, but for some reason I wanted to check the flame shape and quality this time and I noticed that around the outside of the flame I could see droplets of fuel hitting the back of the combustion chamber. Is this normal? Nozzle is a Delavan .85x80B per the Burnham/riello combo kit install sheet. Any thoughts would be appreciated.

Jamie Hall

No -- the fuel should all be atomized and burn cleanly. Sounds to me as though you need -- at the least -- a new nozzle (they don't last forever) and probably some other work. And the whole thing needs to be set up with the proper combustion test instruments -- draughts, O2, CO2, temperature, smoke. It really can't be done properly by eye

Oilfool

I should clarify as rereading my post might give the wrong impression. I serviced the burner last night with new spin on filter, pump screen and nozzle. Checked electrode /nozzle measurements. I had just happened to want to verify that the flame was a good color and shape and noticed the fuel droplets. Last combustion test was last year with same spec components.

Grallert

It's really important to check the combustion after a nozzle change. Even though you are buying a new nozzle the actual firing rate can/will vary ever so slightly. If you opened up an inspection port to view the flame you could be introducing excess air to the mix. But no you shouldn't be seeing those droplets.

Oilfool

Ok. I'll perform a combustion check. Any ideas what would cause those droplets spray on the combustion wall? Should there be a gasket on the flame inspection window? Burnham V8 boiler. No gasket on there now, or since I've serviced it. Thanks

Grallert

There might have at one time been a thin gasket, I forget now. But even opening up that port will throw off the numbers in a lot of cases. Try it when you're doing the combustion analysis. You'll need a digital analyser for this but run the analyser with the port closed and run again with it open. you should see a change in the numbers. You'll want to do the final set up with that port closed.

Oilfool

I understand all that. But no air leak would cause those fuel droplets. I need to verify pump pressure

captainco

Brand new nozzles can be bad. Might have to change again. Yes it is possible your pump pressure is messed up. Without a combustion test it is impossible to guess the actual problem. Air in the system can cause pulsating and impingement until all the air is gone. Bleeding the pump does not get rid of all the air.

Oilfool

Ok. I let it run for about an hour after service so I'd hope all the air is out.

STEVEusaPA

How did you change your nozzle? Did you remove the one set screw, pull the nozzle assembly away from the head and change it? If so, it's possible you didn't tighten it (don't over tighten it) or you didn't put it back together properly.
-or-
Did you remove the 2 screws holding the end cone (head)? If you removed the 2 screws holding the end cone, it's possible to put the end cone back on incorrectly. There is an orientation to it. The wrong way makes the nozzle off-center. Oil will impinge on the end cone and cause a problem similar to yours.
I showed that to a Riello instructor who never knew that. Mostly because almost everyone loosens the set screw and not the 2 screws holding the head to the assembly.
So I would pull the nozzle assembly back out, take a look at it from the end cone, and make sure the nozzle is centered thru the hole.
After that, I would make sure you have properly bled (by properly bled I mean 'power bled') the fuel pump, and checked the pump for pressure and vacuum, and with the power off, ohm out the coil. If none of those work, it's time to bring in someone very familiar with Riello.

Oilfool

I'll recheck my nozzle placement and pump pressure and write back. Yeah I normally bleed by jumping 5&6 and bleeding from the bleeder port and remove the set screw for nozzle assembly. Do you know what coil resistance reading should be nominally?

STEVEusaPA

--Power off--
Terminals 2 & 8, 1.3 ohms +- for the coil.
Terminals 1 & 2, 1215-1485 ohms +- for the coil (going to the valve).
I'd also check the pump piston/plunger to see if it operates freely.

--Power on--
With 5 & 6 jumped out, you should read 42-52 volts AC across 3 & 7.
That's all I remember without going to my cheat sheet...and I only remember them because I had to look them up last week.

Oilfool

Thanks for the values. Do you happen to know the bleeder thread size off the top of your head? I can't find my riello adapter and I know while I'm at work I can grab something from one of my engine diesel fuel pressure kits or drawer of fittings and adapters.

STEVEusaPA

7/16"

Oilfool

Isn't it metric though?

STEVEusaPA

not the bleeder, or nobody told my 7/16" box wrench. The nut under it that often looses is, but just use an adjustable.

Oilfool

Huh. Are you sure your just saying the hex on the bleeder is 7/16" which is basically 11mm as well. But the female threads on the pump I'm pretty certain are a metric thread and that's what I need to know to adapt a gauge from 1/8" npt to it. It's no bother if your not sure.

STEVEusaPA

Oh, don't know that. I just have vacuum/pressure gauges with the metric adapters.

Oilfool

No worries. Thanks for the help.

HVACNUT

Good advice from @STEVEusaPA. Back when I was a pup, Ive busted numerous assembly brackets (the little graphite bar that centers the assembly in the blast tube) before I realized I didn't have to remove the turbulator to replace the nozzle.
Also check the assembly itself. A compression fitting joins the nozzle line to the bulkhead fitting. Loose?
You dont have a bleeder valve on the pump?
The old Mectrons didn't come with one but the 40 series has them. Just remove the plug to prime the pump, then reinstall.
I know Riello specs an 80 degree for the Burham, but almost religiously, I use a 60 degree on all Riello's. Not recommending, just saying.

Oilfool

Thanks. Yeah the 40 has a bleeder and that's where I pressure bleed it. Why do you use a 60 on the riello?

HVACNUT

> @Oilfool said:
> Thanks. Yeah the 40 has a bleeder and that's where I pressure bleed it. Why do you use a 60 on the riello?

I just always found I got better combustion readings with 60 degree nozzles. I change patterns between A, B, and W depending on the boiler. I do use a 70 in a Buderus G215-4, and an 80 with Biasi.
Again, thats just me and I dont want to lead you. 30+ years of T&E, I've made some of my own revisions to my Riello OEM burner guide. Some of there lab tested air settings are waaay off.

Oilfool

The riello manual specifies a type W nozzle. I thought about trying one out at some point, but always stuck wth the B thst burnham recommend