What's likely starting to go when multiple retries before the intermittent pilot lights?

Jim_NY

Home office in the basement, so know the sounds in order: call for heat, clicky-sparky sounding igniter starts pilot, hear pilot burn during the delay while it is is sensed, then main burners come on. Few minutes ago, heard at least five retries before it seemed like the pilot came on.

The S8610U controller status LED was double blinking, which label says means "retry" and then after burners were running displayed a long pulse followed by 6 flashes which label says means 6 uA flame current (and says should be > 1).

So. If it's not a one time thing: dirty pilot tubing, failing pilot sensor, failing gas valve, or ??

If it continues, really would like to have an idea before calling for service, as the last time there was a deficiency in the sequence leading to the main burners, it was unpleasant. (The alternating electricians and plumbers from the HVAC contractor just kept replacing parts and controls until finally on the third day without heat, "the" guy was called in, and it was running 10 minutes later.)

JohnNY

Did you get a pilot at all?

Big Ed_4

run a grounding wire from the pilot assembly to the ground on the control.

wmgeorge

What brand and how old is the unit?

Jim_NY

> Did you get a pilot at all?
Yes. After the fifth retry (from a cold system). Subsequent to that, just cycled off once on pressure, and then right back on, first try. After that was away from the boiler during the night, but heat was received as expected. Will be listening when get back, but it's a relatively warm day.

>What brand and how old is the unit?
Bryant Dunkirk PSB41 Series 30+ yo. And about 8-10 years ago, as mentioned above when - to my ear - only the main burner wouldn't run, most things were replaced over three days (Honeywell S8610U controller, VR8345M4302 gas valve, all or part of the burner assembly, and thermostat and transformer and maybe even the LWCO).

Not the case here or anytime recently, but probably should note that the relay on the gas valve occasionally has been known to chatter, mostly at the beginning of the last couple of heating seasons.

>run a grounding wire from the pilot assembly to the ground on the control
Ah, sounds like something common.

unclejohn

May just be a dirty pilot or sensor. Not sure what your talking about when you say relay on the gas valve. Can you post a picture   

Jim_NY

> May just be a dirty pilot or sensor
Well, that area has not been cleaned for some time.
> relay on the gas valve ?
Just mentioned it for full disclosure. Have not heard chattering since Oct, so possibly not in play here. Don't think anything is visible from the outside of the valve, and relay was just a presumption. Not an electronics tech or EE, or qualified to service a gas valve, but relays and solenoid type components are the only ones that I've ever heard associated with sounds like buzzing and chattering.

mattmia2

Did the chatter happen with both the old and new gas valve?(I think this probably is some other problem, if it happened with the old and new gas valve, probably a bad connection or contact in the control wring somewhere. The gas valve has a solenoid that opens a small supply of gas that controls the larger supply of gas so it isn't called a solenoid valve, those are direct acting on the valve or diaphragm but it is electrically a solenoid.)

Are you getting a pilot flame when it fails to light the main burner? What did the tech that actually fixed it do? Is it a single flame rod and spark electrode combined or are there 2 metal probes in to the flame?

wmgeorge

You can clean the flame sensor or rod with very fine sandpaper like a 600 grit, or finer sometimes the surface gets a little crusty especially if combustion air is from inside the building. After 30 years grounding to burners might need help. There is a very minute low current flow from the flame to the rod, it gets a ground through the flame.

Jim_NY

Just want to be clear:
For the current, so-far one-time observed in-person problem - to my ear - the pilot did not ignite. And no chattering.
For the 10 years-ago problem - whether relevant or not - to my ear - the pilot lit, but the main burner did not.
>Did the chatter happen with both the old and new gas valve...electrode
Only the "new" valve, only after about 6-8 years of use, and pretty much only at the beginning of the season. The manual's diagram shows a single electrode requiring contact with "3/8-1/2" of flame.
> What did the tech that actually fixed it [previous-problem] do?
No clue. After the earlier techs replaced parts and it still didn't work, THE guy got down on the floor with a previous tech, looking into the burner area, and ten minutes later it was running. (Couldn't pay much attention as was running back-and-forth to attend cold elderly people.)
> very fine sandpaper... low current flow...crusty...inside air
I can see from the label that anything above 1 micro-Amp is "good" - that's low, alright. And yes inside air. Unknown if the wiring was replaced at that previous service.