Furnace turns on & off repeatedly before finally turning on for good.


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Old 10-09-09, 12:36 AM
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Furnace turns on & off repeatedly before finally turning on for good.

1. San Francisco Bay area - average temp prob. about 70
2. 1927 wood frame
3. old Holland air conditioner heater installed in the '70s, but has had an electronic ignitor put on it, not a regular pilot.
A friend just replaced a honeywell VR8304M 3509gas valve 'cause a friend thought that was the problem...
4. Natural gas
7. Programmable Thermostat.

So.... sometime over the last year, I'd hear what sounded to me like the furnace was "trying" to start. I'd hear it fire up and then stop about 20 seconds later. Eventually, after 3-4 of these cycles, it would go on and it was fine.

Eventually though, it just stopped working altogether. So this friend who is a handyman changed the gas valve... it still didn't work so he took it to the parts distributor for them to test it or something.... brought it back and still had to work on it a while to get it to work... but now it starts again, but goes through the same on and off type of cycle before it finally starts.... although I think now it starts and stops about 5 times before finally staying on.

I also went into the basement to see what was happening, and notice that the ignitor makes all kinds of clicking noises for a while, before it actually ignites and a big whoosh of fire comes out the front of the furnace (well, a few inches of flame do) and then it shuts off and the ignitor starts to click again. I also noticed that between all the starts and stops I do smell some gas... not a lot, but I'd rather not smell any!

I'll add that I also removed the thermostat myself and just hooked to wires up to each other because the thermostat numbers were flashing and unreadable and I wanted to eliminate it as a source of the problem... but the problem is still there - it goes through the same on and off routine and eventually starts up.

Any suggestions would be most welcome! Thanks.
 

Last edited by ensatina; 10-09-09 at 12:40 AM. Reason: clarity
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Old 10-09-09, 02:31 AM
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You don't need a handyman for this job. Call a service contractor to check this problem.
 
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Old 10-09-09, 04:46 AM
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At apprx 35yrs of age its time for a new system, with all the rebates and tax credits now is the time. You will be more comfortable and reduce your energy costs.

before it actually ignites and a big whoosh of fire comes out the front of the furnace (well, a few inches of flame do) and then it shuts off and the ignitor starts to click again. I also noticed that between all the starts and stops I do smell some gas... not a lot, but I'd rather not smell any!
Do you really think thats safe
 
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Old 10-11-09, 02:19 PM
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Was not looking for the obvious replies I received...

Yes, obviously the smell of gas is not safe so that is why - though I didn't state it - I turned off the power to my heater since prior to posting my question. I'm not stupid. If anything I'm being overly cautious.

I also know my furnace is old and that I "should" replace it - but as with many people -this is not a good time to do so financially... it has asbestos and all, and will be a very pricey undertaking - even with tax credits and rebates.

And, just telling me to get a service contractor to do this rather than a handyman doesn't tell me much at all.

I was really hoping someone could tell me what they think might actually be causing the problem I'm describing so that I can then make an educated decision....

(I now also have to wonder if a guy had asked this question instead of me, if someone out there might have ventured a few guesses and given some real information....)

Anyone out there willing to lend a hand?
 
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Old 10-12-09, 07:37 AM
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You may have dirty burner(s) causing delayed ignition, explaing fire flash out the front. And of which when you get that delayed wawawaWOOF!, when the burner finally is set off, that might put out the pilot light sometimes. (Like how Red Adair used to put out oil wel fires with that same principle using dynamite or whatever. The old "fight fire, with fire", adage.) And you smell the gas due to delayed ignition as well. You can try to DIY clean the burners if you can, and see if that cures it. .

If ever though you have issues with flames being snuffed out or even flicker only when the blower comes on, get the pro in there fast, as you could have a possible life-threatening condition with a cracked heat exchanger and CO gas!
 
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Old 10-12-09, 09:09 AM
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I agree with everything "ecman" said, cleaning the burners would be the first place to start. My recomendation would be to contact a good local HVAC contractor and have them do annual maintenance on the sysytem. This would correct your problem as well as identify any other issues there may be, as it seems your looking to try to make this system last a little longer its your best option.

For the record, I had no idea if you were a man or a woman and wouldn't have cared. Seems like its your hang up
 
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Old 10-12-09, 10:47 AM
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My guess is that it's probably not a burner problem, although cleaning and inspecting the burners is good routine maitenance if it hasn't been done in more than two or three years.

It sounds like you have a Honeywell intermittent pilot ignition control system retrofitted on you furnace. These tend to be excellent systems ----I've had one on my gas furance since 1985.

These have a circuit that electronically verifies that the pilot has been lit. When that is verified, the main burner gas is turned on. If that signal fails, it shut the main burner off.

It sounds like you aren't getting that signal reliably, or it's not being detected properly by the ignition control module.

The odds are that the module is bad, but it could also be a dirty pilot burner or defective wiring, bad ground or something else.

I'd look for a good repairman who can analyze and correct this problem rather than attempt to sell you a new furnace.

You should also have him do the routine cleaning and maintenence work need on the equipment, and inspect the heat exchangers to make sure they are still good.
 
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Old 10-12-09, 12:42 PM
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Thank you ecman51, dun11, and SeattlePioneer!

Finally some info I can sink my teeth into!

I will definitely check into all of these suggestions and report back (though it might be a while as I'm going out of town... )

dunn11 - I've actually never gone there (the man-woman thing)... but after receiving the first two posts almost immediately and hearing nothing beyond that for several days I was discouraged, and pondered what to do next and continued to wish someone else would answer but no one did - and as I wondered why, it was a question that crept into my mind. After all, it's not as if its never happened before! But perhaps it would have been better to have left it out of my post - I hope *I* didn't offend anyone.
 
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Old 10-12-09, 10:22 PM
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Update

Hi all,
I checked with my handyman and here is all the work that was done on the furnace before reporting the problem here. This also address the suggestions everyone gave:

- pilot burner: first thing my handyman did was clean it... (although since it still isn't working, I may give it a cleaning too just in case.)

- ignition module: replaced and tested. Problem persists.

- faulty wiring:fixed the bad ground, also tested without thermostat.

When everything he initially did didn't work, he took the Electronic control module, ignitor and new gas control valve for testing at APD on a flow bench. That is when the grounding problem was identified and corrected, and everything was reinstalled into the furnace.

- heat exchanger: I'm going to have Pacific Gas and Electric out on Thursday to look at it and the rest of the system... if I'm lucky I'll get someone who knows what they're doing... if not then I'll break down and get a heating specialist.

My hunch is that I had two problems...one's been fixed, one hasn't. I think the bad ground may have been what stopped it all together because it turns on again now, but the on and off problem is a separate problem... just wish I knew what is going on... plus it's getting colder and a storm is coming in tonight!

Any other suggestions are welcome. Thanks all!
 
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Old 10-14-09, 05:23 AM
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I apologize for my brief and incomplete answer to your problem. The reason I suggested a contractor had nothing to do with being male or female as I am sure your "handyman" is a man. The reason was because the symptoms you described indicated a possible dangerous situation that needed to be addressed by a qualified professional. Contractors carry insurance bonds that cover them in liability cases. Handymen do not have liability coverage.

Trying to help someone online with a problem such as you are experiencing is a liability problem for me or anyone else on here that spend some of our free time trying to help others. I try to help where I can but if the problem is dangerous such as this it is best for me to advise you to hire a professional that can do the job properly.

Again my apologies for the brief reply.
 
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Old 10-14-09, 07:39 AM
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Same problem with a twist

Same problem with a twist:

My condo has a mid2late 80's Janitrol - from what I understand it's as cheap as cheap gets.

My furnace will turn on and off the same way as described by ensantina, but only when the heat is being triggered by the programmable timer. It will not play this game when I go to the thermostat and bypass the programming and turn up the heat to 80 - in this case the furnace will ignite, blower will turn on and stay on.

The catch is, I just replaced my thermostat and the same problem persists. So that rules that out.


Any ideas?


Thanks,
Chris
 
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Old 10-14-09, 08:01 AM
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Can't necessarily rule out the thermostat even then. Maybe you can, but I can't, if I do not know when the first stat was put in, and if that first stat ran trouble free for a long time, befire giving you the trouble. And that the replacement stat is exactly the same one that has exact same wiring and same jumper wire in it and same dip switches, etc.

So far you have told us everything to lead one to believe the stat is the cause. It is either that, or you have one heck of a coincidence playing games with you.

It does this everytime you do it?: You can turn up the heat to 80, and every single time it works fine. But does not run fine on programmed heat?
 
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Old 10-14-09, 10:03 AM
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The original thermostat was a Honeywell. It was there since I moved in which was this past March. Back then the issue did not exist.

The replacement is a Rite Temp. When I put it in last night, I tested the fan, cooling and heating (by turning it up to 80) and it worked fine. This morning at 6am it was the same situation with the furnace going on and off for like 10 - 15 minutes. Since I have gas, I have a jumper in place for that and another jumper in place for HVAC Single Power.

The wiring is indeed new because I moved the stat away from direct morning sunlight into the hallway, closer to the HVAC return. (However the problem did start happening when the stat was in the original spot so I don't think it's a matter of the location.) I double checked the wiring to make sure that W, Y, R and G are where they should be on both ends.

Tonight I will reprogram the stat to turn the heat on right in front me so I can witness anything awry.
 
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Old 10-15-09, 01:23 AM
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Motown HVAC -

Thanks for the explanation. I can understand the liability issue... (for one, I'm a risk manager...) but after all, couldn't you bring up the liability issue with a lot of the problems described here - especially given that you know little about the person on the other end and what they're going to do with the info you give?

That said, what I'm really curious to know what it was in my description that sent up those red flags!

(...and for what it's worth, I wasn't referring to my handyman's sex! )
 
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Old 10-15-09, 05:02 AM
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before it actually ignites and a big whoosh of fire comes out the front of the furnace (well, a few inches of flame do) and then it shuts off and the ignitor starts to click again. I also noticed that between all the starts and stops I do smell some gas... not a lot, but I'd rather not smell any!
Also from some of the symptoms you describe there is a possability of a cracked heat exchanger. A cracked heat exchanger = carbon monoxide in the living space, carbon monoxide in the living space = death.

Though I and others don't doubt your hanymans skills, if he has to take suspect parts to be tested somewhere else he is in over head. You are literally playing with fire, sorry.
 
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Old 10-15-09, 07:48 AM
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You said you are using jumpers. Are you jumpering the pressure switch?

Do you know that in jsus the last couple days, where I have worked on furnaces, I came across writing from our furnace man that said the secondary(secondary heat exchanger -which is the condensing lower heat exchanger) was replaced? He found cracked secondary heat exchangers.

It is typical when a problem first develops regarding the internal venting of the furnace, that the pressure switch can either work, work for only short periods of time, or not at all. These are really really sensitive to slight changes in vacuum. Problems can range from the pressure switch being bad, to a backup of condensate drain water, to a bad vacuum hose/loose, to a blockage right in the nipple that comes out of the ventor fan that the pressure switch's vacuum tube is connected to, or a clogged combustion intake screen (some furnaces have that -most do not), any blockage in the intake or exhaust piping, to even cracks in either of the 2 heat exchangers.
 
 

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