strange furnace behavior, please help

Hi All,
My furnace stops before the set temperature is reached. I am in NJ where it is rather cold these days. I have been observing the furnace closely and this is what I saw.
NOTE: This only happens in the morning, I set the thermostat really down at night (55F). Day setting is 66F.
When thermostat kicks off the heat, my Lennox high efficiency (model G26) turns on the air intake pump (brings air in from outside of the house). After about 10 seconds, burners come on. Then 10-15 seconds after that - main fan comes on. After about 5 minutes, fan and the burners shut off but the fresh air intake fan keeps running and this fan runs forever unless I shut off things from the thermostart and restart. After I do this 3-4 times, things run fine all day.
When the system was working fine, burner and the air intake fan would stop first (after proper temp was attained) and 20 seconds later, main fan also would turn off.
Thermostat doesn't seem to be the culprit because I stood there to see if there is any click indicating a signal from it to the unit.
So, it seems that the problem happens only when the home temp is very low.
Any ideas or thoughts that would help me troubleshoot this would be highly appreciated.
Thanks in advance.
Ronie
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When a work lifts your spirits and inspires bold and noble thoughts in you, do not look for any other standard to judge by: the work is good, the product of a master craftsman. - -- La Bruyere
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Not....This is a discussion board. If accurate info can be obtained for a quick and inexpensive fix then why not ask? You'll never know unless you ask.
All this " competent* licensed, professionally trained " is for the most part bull. Many argue that only the " competent* licensed, professionally trained " individuals can safely accomplish a proper fix, when what they really mean to say is that I want your bussiness/money. .
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low.
trained
Wrong. Take a look at the NGs posted to. AHR and AHVAC.....the HVAC group is NOT a discussion group for homeowners, was never set up for that.

Really? Bullshit. If the guy was trained and knew what he was doing, there would indeed be no reason to ask, and there sure would not be a need for a local, state and federal level licence to do that work. All the inspectors could go home and call it a day.

Again, wrong. Every single one of us in the HVAC group, BTW, NOT a good representation of the AVERAGE tech, since the AVERAGE tech has no clue what Usenet is, much less how to use it, have and will continue to give advice when and where practical, and have given away more work in a years time than many make in a year, IF that is, you are the business owner, and not a tech working for a tight ass. Now, I dont know about you, or what you do, but you stop and consider this... We get to work on every unit ever made that is still around. Granted...the general operation is the same, but the controls are sometimes worlds apart...yet, we, are supposed to know everything there is about it. We all do a pretty fair job when we can see whats been monkeyed with and torn up and not wired correctly in the past. We can make things work that most people would give up on....we can find a way around any issue, and thats what we are supposed to do. Now...do that same work, blindfolded. That is what you are asking when you ask how to fix a Carrier gas unit that wont run with no other information. What model Carrier? What serial number? Hows it installed? Filtration? Service records? Condition of AC coil? Blower? RPM of blower? combustion gas temps? Heat rise? etc... Yes...to PROPERLY repair a unit, you better know. And chances are, those that will bitch the loudest that this is all bs, are the ones that know the least.

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Not wrong. The original poster posted the message to multiple groups. One of them was alt.home.repair. Anyone can ask for help on this group.

You seem to think that a "licensed" person can only effect a proper repair. Don't make me laugh.

Again you are wrong. All this info can be obtained without a license. All it take is a little research, common sense, and a willingness to commit to a task in a safe and orderly manner.
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homeowners,
Then cut the damn crossposting and cluttering up of our group. I know you are not posting from here, and I am not posting these replies from AHR...

there
a
inspectors
Oh I am not trying to insunuate that..since most trained monkeys can fuck up a unit, I see daily what the untrained can do..and its amazing... Here however, ONLY a licenced and insured person can BUY PARTS to repair the unit, and of course, if they get them online, and its not right, when someone like myself gets called for the sales inspection when they are selling the home, as required by most towns and jurisdictions here, we get to fix it right....finally.

of
in a

a
Granted...the
all
you
information.
gas
the
Wrong? Not even...how about you pop me a complete wiring diagram, and parts list for a BRH* York model. :) This isnt a joke...its proving to you that unless you are a dealer, or OWN the unit with a owners manual...(hint...I said COMPLETE) that you wont have it on the net.....tho I can get it on the net...

Never said otherwise. Many states do not require, nor have a licence OTHER than the EPA refrigerant licence to do HVAC work. You will see these states switch over shortly to licenced status as the EPA continues to increase the limitations on what you can, and cant do. We also get to read about all the people that think they were doing the simple stuff too...normally it starts like: Local man killed while attempting repair on furnace... Pros get hurt as well, it comes with the job, but the chances of us burning your home down due to a gas valve pressure that was set wrong, or the failure to install the correct size nozzle is slim to none, AND, if on that slim chance it happens, we are insured to take care of it.
Keep in mind, that I was licenced in two of the more strict states, CA and NC. Where you are, it might not matter, but the point of the entire discussion is, that IF you dont know what you are doing, leave it alone, since....contrary to what you MAY think incorrectly, you wont get the full story on correct repairs over the net, and EVEN on the slight chance you do...can you afford to go buy the materials needed to correctly do the repair, or will it be cheaper to simply pay the man? Normally, its much cheaper to pay the man...(I love this part of our tax season....as I know EXACTLY what I have in tools on the vans...all of them)
Now...if you look at the postings you and I have here, I dont fully disagree with you, but I do think that perhaps you are a bit misguided in your logic. Also, I notice that you completely ignored the fact that I said we give stuff away....stop and think about this before you try to flame back: I own the company. I also love this work. I dont get out EVERY day and work, as there is an office to run, other techs to check on, jobs to bid, permits to pull (cant do that without a licence here either) and such. If you go to work, and put in say...15 hours, you dont just expect, but you demand that your employeer pay you for that day. My guys understand that there is a time and a place to simply tell the people...Have a good day, and thanks for calling us...oh..the bill? There isnt one. That means......they MIGHT have worked for free..isnt that strange? Isnt that odd? Isnt that just freaking incredible that some pro just came into your home, spent a hour or two getting you heat again, and said...no charge? It happens...deal with it.
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One other item is needed
The willingness of others in the field to not hoard or otherwise inhibit the knowledge (schematics ect) of the device involved.

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Then you can take that up with the States Licence Board..and my insurance company...and the makers of the products, that clearly state that a non trained person NOT install or work on the unit.

OTHER
states
the
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when did you last change the filter ?????????????????
ronie wrote:

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The only way the filter would be a problem is if the furnace is shutting off on high temp limit --not enough air getting thru the heat exchanger. Then the furnace surely would not run correctly when the circulating air is warmer.
It sounds like it might be some kind of problem in the control circuitry (call a mechanic), but I noticed a posting here earlier where the pvc intake/vent pipes were freezing up. I am sure this will cause strange behavior at the furnace when it happens, so it might be worth inspecting the vent plumbing the next time this happens. I would expect freeze-up only to be a possibility at very low temperatures, colder than NJ, but who knows?

low.
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where
closely
down
fan
restart.
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sounds like you have a sicking relay.
jb books books mechanical kookamunga
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From original Poster:
Another thing I noticed I last night is that couple of rooms in the house are not getting much air. If I touch the vents, they are warm but can;t feel any flow. I wonder if this is somehow causing premature furnace shutoff.
PS: to Steve @ Noon-Air Heating and A/C - I will call a professional but I had some time since the furnace does work.
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Then you are gonna love this question...when was the last time you had it serviced? Meaning, the AC too if equipped?
Gonna be puting pics on the site soon of what we pulled out of a coil and blower that really made life fun for a couple a while back..
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CBhvac wrote:

Was it well done or still medium rare????
Bob
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There is a safety switch./contol that will shut the gas off if the furnace temp goes above a preset level. If you only experience this problem when calling for the 55 to 66 temperature increase then you would expect longer fire time and a possible overtemp problem to arise is something else is in error. (dirty filter ect)

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snipped-for-privacy@mucks.net wrote:

duhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
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would that be the combustion blower relay? Tony D.

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I generally keep stuff well maintained but doublechecked filter is clean air in/out flows freely ducts clean (professionally cleaned 2 years ago) blower fan - squeaky clean.
Here is what I DID find - there was this knob attached to a flap inside the vent that was slightly turned and thus blocking the vent a little bit. I think this is leftover part of an old style humidifier. Part of the vent that was blocked is responsible for carrying about 65-70% of the air from the furnace. I just corrected it about 10 minutes ago. Another thing I did on the thermostat is to disable the Intelligent adaptive system for temperature control on Honeywell Chronotherm III thermostat. Unlikely that it has anything to do with the problem though.
Will post again in couple of days to let you all know if air flow was indeed the problem.
Many thanks for all your help.
Ronie
Anthony Diodati wrote:

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Hi snipped-for-privacy@mucks.net, hope you are having a nice day
On 30-Jan-04 At About 13:44:28, snipped-for-privacy@mucks.net wrote to All Subject: Re: strange furnace behavior, please help
t> From: snipped-for-privacy@mucks.net
t> On Sat, 31 Jan 2004 01:06:34 GMT, richard p dawson <rpdawson@ wrote:
t> No...In the most part I know some of you won't divulge info because t> you rather make a buck off of it.
I won't make any money off of you since I am probably not in your area. I don't give out any info due to the fact that it may cause damage to your property or even kill you if you misunderstand the info and do it wrong. also, there are so many different units and control schemes that it isn't possible for me to know what you have. it is also due to the fact that I don't know what that last tech or you did to it that may bypass safety features.
-=> HvacTech2 <=-
.. "It's a small world, but I wouldn't want to have to paint it."- s.w.
___ TagDude 0.92+[DM] +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ spam protection measure, Please remove the 33 to send e-mail
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