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-   -   Can a standing pilot use electronic ignition? (http://www.diychatroom.com/f17/can-standing-pilot-use-electronic-ignition-164682/)

richapple 11-25-2012 07:08 PM

Can a standing pilot use electronic ignition?
 
Can a standing pilot in a gas furnace light itself automatically (with the clicks of electronic ignition)? But then be a normal standing pilot and just stay on all the time once lit?

Or is a standing pilot always the type you have to light with a match?

____________________

I'm going to be a little unforum-like and add way too much, but anyone knowing the answer to the above, please feel free to answer just that without reading any of my blah blah below.

I have always assumed the pilot on my 23 year old York forced air furnace is an intermittent pilot that lights when the thermostat says "go time" because it does light itself automatically and is not the type of pilot one needs to light with a match (while perhaps turning a knob while holding down a red button with one's nose, etc.).

I did some fiddling with the thermocouple to get it to come on this year (after having the summer/fall off), and unlike 10 years or so ago when I first met the thermocouple, there was nothing clear about what I did (like 10 years ago when the thermocouple had slipped down so it was no longer in the pilot flame at all).

My concern is that until today, anytime I've turned the thermostat all the way down and gone to the heater to see what I can do (after it failed to start heating and shut itself down), that pilot light is out. Now it merrily stays burning, even after it has been off for a time with the thermostat way down, or when it has failed to start up again and the thermocouple has informed the entire system that there is no flame, so shut down all the gas.

If the problem is in the heater "brain" or whatever is supposed to kick in on shutdown and turn off all the gas including the pilot (in other words, my pilot is supposed to be an intermittent pilot), then it seems that the pilot continuing to burn could be part of a vicious cycle that keeps the thermocouple hot when it thinks it's cold, so when it is supposed to measure an increase in heat, it concludes "there is no flame 'cuz it's no warmer here than it has been".

Evidence to support the above (which of course I've completely made up and obviously I'm not an HVAC person in the least) is that if I turn down the thermostat and turn off the heater (knob on heater from On to Off) and wait 15 minutes until the pilot area is all cool, then when I turn the furnace back to On and put the thermostat up - voila - heat!

If a standing pilot does always need to be lit with a match (and mine is supposed to be intermittent), then I figure that continuing gas to the pilot is a bad thing and I'm in over my head for fixing it. Otherwise I'm thinking replacing the thermocouple might be worth a shot.

Thanks...

NiNe O 11-25-2012 07:12 PM

http://www.hvacpartsoutlet.com/image...l/LH680005.jpg

not quite what you asked for, but close

richapple 11-25-2012 07:22 PM

Hmmm... 'kay - a picture is worth a thousand words and all, but is that what this is? An electronic ignition to light a standing pilot the first time?

NiNe O 11-25-2012 07:31 PM

it's an electronic ignition that lights a standing pilot everytime. like I said, not quite, but close.

Missouri Bound 11-25-2012 07:45 PM

Rich.....a couple of things.

A standing pilot gets lit once and stays lit, whether the furnace runs or not. As long as the gas is turned on to the furnace, the pilot is lit.
An intermittent pilot is a bit more difficult to explain. IF your pilot is intermittent, or electronic ignition, what happens is that when you turn the thermostat up the pilot gas valve opens and an ignition source comes into play to ignite the pilot. After that happens the thermocouple is there to prove the pilot flame, and then the main gas valve will open allowing the burners to fire.
They are two different things. The type of gas valve is completely different in the two applications. If your standing pilot goes out by itself it has a problem, either gas pressure or sometimes a draft will blow it out. Any type of ignition system for a standing pilot would still require the user to manually operate the gas valve. What Nino posted is not for a standing pilot assembly.

carmon 11-25-2012 08:00 PM

I think you are talking about an auto re lite.... they are not something you would install on your furnace.... your furnace should work as is...if it does not you need to repair it not modify it......:eek:

richapple 11-25-2012 08:03 PM

Thanks, Missouri Bound,

I do think my pilot is not the "standing pilot" type, but is of the intermittent type. From your reply and the other (NiNe )) reply my take-away so far is that no, not needing to be lit by a match does not confirm for sure that my pilot light is indeed an intermittent pilot.

My history with it and how I'm pretty sure I've seen it function (from back to when I first fixed the thermocouple position and more recently when I just kind of touched the thermocouple even though I didn't seem to move it at all) is that when the thermostat says "warm enough" and the heat and blowers shut off for a while, that pilot light has also been out.

My concern now is that the pilot light is staying on (and lit, which is a good thing if there's gas there) even when the heat and blowers are off, or even when the heat and blowers failed to come on. (What is clearly intermittent is my thermocouple.)

Your reply does suggest a whole new problem (that my pilot is a standing pilot that uses something other than a match to be initially lit, and it's a problem that over the years I've observed it being "out"), but again, though I haven't eliminated the possibility, I'm still thinking my pilot is of the intermittent type. (Or maybe your reply does eliminate the possibility of my having a standing pilot, since I think you refer to "user manually operate the gas valve," and in my case, no, I turn on the entire furnace (Off to On) with the thermostat down, then it is when I turn the thermostat up and trigger the furnace coming to life, that is when the pilot lights.

So yeah, I am convinced I have an intermittent pilot, and now I just wonder why it stays on sometimes.

richapple 11-25-2012 08:07 PM

Carmon - thanks, and no no no, I would not try to customize this. The most elaborate thing I might try is to replace the thermocouple, but only with the exact one the unit needs. And being that it's 23 years old, they might get me on planned obsolescence. -- Thanks!

carmon 11-25-2012 08:18 PM

you should be able to get a thermocouple ..... its worth a try.....:thumbsup:

Missouri Bound 11-25-2012 08:35 PM

Can you take a picture...and post a model # ? It should be easy to figure out with those two things.:yes:

richapple 11-25-2012 09:22 PM

2 Attachment(s)
The furnace is a York PIECD12N04901, and I found no info at the York site or just searching for that model number.

The photos are both of the pilot light when it has remained on after the heater/blowers have turned off. The "with flash" is probably easier to see what is there, but know that the pilot light was actually on though overwhelmed by the camera flash.

The "no flash" one shows the pilot flame, and from what I've read it would be better if adjusted to not be solid blue, but blue with a yellow tip. When I take the pieces apart to see about replacing the thermocouple I will try to figure out what to turn to adjust the pilot a bit.

The thermocouple is out of view, behind that plate just to the left of the pilot light. It looks like others I've seen on-line, with kind of a larger diameter cylinder base and then a metal rod sticking up into the pilot flame from that. Kind of like a simple wand type soldering iron.

New info since I first started this thread is that since doing my full shut down and letting the pilot area cool, the heater has worked and with the temps coming down (well, beach town south of San Francisco in California, so not as cold as lots of other places!) the thermostat on/off has continued to work, and though most times between furnace on times I've gone into the garage and seen that the pilot is on (like just now with the photos), there have been a few times that the pilot is not lit. And yes, with the next thermostat trigger it gets lit.

techpappy 11-25-2012 10:25 PM

Here's my theory...you do have an intermittent pilot and it initially lights upon cold start up however the pilot valve is leaking causing the pilot to stay lit when it should actually shut off THEN when thermostat calls for next heating cycle the control senses pilot is still on but, out of sequence and does not allow re light ..need new gas valve or pilot valve depending if separate or combination valve .

carmon 11-26-2012 12:19 AM

Quote:

Originally Posted by techpappy (Post 1060494)
Here's my theory...you do have an intermittent pilot and it initially lights upon cold start up however the pilot valve is leaking causing the pilot to stay lit when it should actually shut off THEN when thermostat calls for next heating cycle the control senses pilot is still on but, out of sequence and does not allow re light ..need new gas valve or pilot valve depending if separate or combination valve .

that is very possible......i must agree..well done....

richapple 11-26-2012 01:15 AM

I agree that techpappy is probably pretty close to what is happening, and the key thing (and obviously the bad thing/dangerous thing) is that the valve that should be shutting off the gas to the pilot (I think it is a combination valve on mine) is not shutting it off sometimes. That's what I was trying to say when I was babbling about the "heater brain" in the long second half of my original post (not sending the signal to shut off the pilot). So yeah, it's a "gas leak" in terms of gas coming out when/where it shouldn't, but it's not a like an incomplete valve closure and a tiny bit is leaking - the pilot is simply staying on, full.

So somewhere either the trigger to the pilot gas valve is not happening each and every time, or it is and the valve is not responding and shutting off the gas.

My take at the moment is that either of those two things being the case is not quite so dangerous, but if it was that the trigger was happening and the valve was closing, but then it was not closing completely and it was letting a tiny bit of gas leak out (which wouldn't appear as the full pilot light when I look at it), then it could just as easily close completely (enough for the flame to go out), but then start leaking that tiny bit. And if that was the case I would think there would be a big noise (as in explosion and a messy garage going up in flames) when the thermostat next started up the normal process by clickety clickety "lighting" the pilot.

As for the pilot already being on and the next heating cycle getting confused because the pilot is already on, I'd think so if that happened every time (or, uh, didn't happen - meaning the heater didn't come on every time the pilot has remained on). But most often, at least tonight, even with the pilot behaving like a standing pilot and already being on, the heater/blowers have been coming on. I think the intermittent problem of them not coming on every once in a while is due to the flakiness of the thermocouple. So I'd add to techpappy's no doubt correct "need new valve" a "need new thermocouple". (The internets seem to indicate the life span of a gas furnace to be 16 to 20 years, possibly longer if routinely cleaned and serviced - which my 23 or 24 year old one has, uh, not been.)

While I'm a big DIY'er for most things, I have to admit that I'll probably balk at moving forward with this one on my own. Finding the part (combination valve) already seems less than possible, and if I could find the exact one, it would likely be a couple/few hundred dollars, which is quite a bit to put out there when it's not a 100% guarantee to fix the problem.

In the mean time I will probably shut it completely down when I'm gone all day at work and stuff. No sense taking a risk AND wasting the gas.

av-geek 11-26-2012 02:06 PM

Do you remember hearing a TICK...TICK...TICK.. noise coming from the furnace at the start of the call for heat cycle? My parents 25 year old Bryant furnace has the same style intermittant pilot light as Nine-o posted. If you remember hearing that noise, then you most definitely have an intermittant pilot. Also, you could look for a "glow bar" Most newer furnaces use those instead of spark igniters. You should see an object that looks like a small oven heating element glowing orange in front the pilot right at the call for heat, when the pilot ignites....that would confirm intermittant pilot too


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