Riello delayed ignition

iix

Having an issue with a riello F5 in a peerless wbv4. Eliminated the jack and air shutter due to leaking seals and now I'm having issues with delayed ignition.

Compared nozzle, air and pump pressure vs peerless's oem specs
1.0 60W delavan nozzle
155 psi on the pump
2.5 on the turbulator

Burner running I have:
Draft @ breech -.03
Draft OF -.01

Checked prepurge timing at ~12.5sec.
Set the burner at 12% co2 and the delayed ignition is very apparent. I had to cut the air back to almost 13% co2 to get to light every start.

Anyone have any suggestions? At this point I'm thinking about lowering the draft slightly but the damper is wide open as it is.

Robert O'Brien

Electrode gap good?

STEVEusaPA

The electrode gap really doesn't matter if the porcelins are intact on a Riello. Different transformer on a Riello. Was just at a Riello class on Wednesday taught by well-known Riello guru Joe Sacco. He had the electrodes pointing away from each other and the spark jumps the gap and won't ground to the head or sides.
The problem started when you removed the jack. So...
If you did the proper checks for incoming voltage, motor voltage and ohms on primary and secondary coils, I would think its these 3 things either separately or together:
1. Too much air from air band open too far.
2. Too much over fire draft
3. Improper adjustment of the turbulator. If you move the turbulator toward a higher number, the burner will not be as sensitive to negative draft in the combustion zone.
And you're sure you have the right nozzle? Also, and this doesn't matter as much with the Riello, but was the cover on when you were testing and adjusting?
When you cut the air, did you still have true zero smoke?

I don't understand the delayed ignition. Either it lights immediately, or it goes back into pre purge. If you heard spark but no flame....then flame, I would double check both ohms readings for the coil, and check the plunger in the pump.

Robert O'Brien

Too close together or too far forward will most definitely cause ignition problems

iix

I can't say for sure it was the air shutter being removed that directly lead to the issues. Last service was month ago, boiler vacuumed, nozzle, filter, and strainer were replaced and the jack removed at that time. I was called back out for intermittent lockouts (3 times since service).

Nozzle was correct and the electrode gap was good. Combustion was checked with the cover on. I didn't take a look at the voltage at the burner. With the air band open more the burner would either not light or take 1-2 seconds after the solenoid opened. Pressure was fine every time the valve opened and with the delayed ignition there was smoke so there was fuel in the chamber.

The draft regulator was already set pretty far open. I'm thinking occasional excess draft is the source of the lockouts but something else has to be going on if I cant get it to light with the air band at the correct point.

I'll get back over there and try adjusting the turbulator forward and see if that improves things.

rick in Alaska

I haven't had any delayed ignitions on a Riello, but I do know they like positive pressure in the firebox. I wouldn't think a -01 would cause issues though.
Does the pressure pop right up, or come on sluggish?
Might be possible the primary control has a weak spark at times. You might try changing it and see what happens.
Rick

aircooled81

I had three or four peerless purefire (natural gas though) delayed ignition over the coaurse of a year (within warranty).
I found there were two causes for the same problem. The problem was the ignitor was supposed to provide an imidiate constant arc dudring the firing stage, at first I had thought the tic-tic-tic was normal ignition. Come to find out the arc is supposed to be constant and imidiate.
Two parts most common to have failed, the ignition board (not putting out the required voltage) or the ignitor and cord (no visual signs of defect though).

If that's any help?

dav

On a riello with a buderus with delayed ignition I jack the pressure up and it fires every time. I think you said you were firing at 1.55 psi with a 1 gal/he nozzle. That puts you at 1.25
You could try upping pressure to 190 and down size nozzle to .9 that will fire you at 1.24 gph. Then check combustion. 

STEVEusaPA

@dav the post is almost 4 1/2 years old...