Re: Carrier Furnace Ignition Lockout - why?

> Hi all,
> Got a furnace problem that has me running in circles. Perhaps some
> quick advice can point me in the right direction at least. We have a
> Carrier furnace, older that 5 years old, and this year is has been
> failing to ignite, flashing error code 14 (ignition lockout) causing
> it to wait 3 hours before the next attempt. FYI here is the code
> legend:
> #14 default= ignition lockout, control will reset after 3 hours. Refer
> to #34.
> #34 default= ignition proving fault. Check for gas valve turned off,
> oxide build up on flame sensor, main shut valve turned off, Green wire
> must be connected to furnace sheet metal, proper flame sense microamps
> (.5 micro amps DC minimum), inadequit flame carry over or rough
> ignition, low inlet gas pressure.
> Now, a little history:
> 1) Four years ago we had a crawlspace dug out and the project and the
> project went poorly, causing the basement to be exposed to excessive
> dust and moisture for much of that winter.
> 2) This winter we began having trouble with the thermostat. The
> backlight would not light, it would display gibberish, and sometimes
> not display anything. Shortly thereafter we noticed that this
> behavior happened at the same time the furnace had the ignition
> lockout.
> 3) We called an independent contractor and described the problems.
> The tech wasn't aware or (or wasn't concerned with) the codes and was
> only concerned with the thermostat. He indeed found and straightened
> some bent pins and we could notice a tighter fit when we closed the
> cover of the stat. He figured that solved the problem, and he never
> even looked at the furnace itself.
> 4) A month later the lockout recurred, and the contractor sent another
> guy on the callback. The furnace had restarted by then so he didn't
> see the codes, and I don't think we mentioned them when we made the
> emergency call. Anyway, he was certain it was an overheating issue
> and when he went in he found the coil was *very* dirty (from the
> crawlspace project) and had to scrape it with cleaning solution.
> 5) Now, another month later, the problem has returned.
> I don't know which direction to take this. I don't want to keep bring
> techs out who don't fix the root cause (whatever it is). Before I
> invest in another call, perhaps someone could tell me:
> - Could this problem really be caused by a defective stat or dirty
> coil? The stat HAS been loose and the coil HAS been dirty, but the
> error codes don't mention these, and don't seem to allude to them.
> For that matter, if the ignition is locked out, will it cause the stat
> to act funky when I use it? I don't want to pay for another scraping,
> or a new coil, if I don't have to.
> - If I call the techs back, after I make sure they are aware of the
> codes, what directions should I give them?
> - Is there anything I can check on my own fairly easily before
> resorting to another callback?
> Thanks for any advice,
> -Larry

> ltravi...@gmail.com wrote:

> > Hi all,
> > Got a furnace problem that has me running in circles. =A0Perhaps some
> > quick advice can point me in the right direction at least. =A0We have a
> > Carrier furnace, older that 5 years old, and this year is has been
> > failing to ignite, flashing error code 14 (ignition lockout) causing
> > it to wait 3 hours before the next attempt. =A0FYI here is the code
> > legend:
> > #14 default=3D ignition lockout, control will reset after 3 hours. Refer=

> > to #34.
> > #34 default=3D ignition proving fault. Check for gas valve turned off,
> > oxide build up on flame sensor, main shut valve turned off, Green wire
> > must be connected to furnace sheet metal, proper flame sense microamps
> > (.5 micro amps DC minimum), inadequit flame carry over or rough
> > ignition, low inlet gas pressure.
> > Now, a little history:
> > 1) Four years ago we had a crawlspace dug out and the project and the
> > project went poorly, causing the basement to be exposed to excessive
> > dust and moisture for much of that winter.
> > 2) This winter we began having trouble with the thermostat. =A0The
> > backlight would not light, it would display gibberish, and sometimes
> > not display anything. =A0Shortly thereafter we noticed that this
> > behavior happened =A0at the same time the furnace had the ignition
> > lockout.
> > 3) We called an independent contractor and described the problems.
> > The tech wasn't aware or (or wasn't concerned with) the codes and was
> > only concerned with the thermostat. =A0He indeed found and straightened
> > some bent pins and we could notice a tighter fit when we closed the
> > cover of the stat. =A0He figured that solved the problem, and he never
> > even looked at the furnace itself.
> > 4) A month later the lockout recurred, and the contractor sent another
> > guy on the callback. =A0The furnace had restarted by then so he didn't
> > see the codes, and I don't think we mentioned them when we made the
> > emergency call. =A0Anyway, he was certain it was an overheating issue
> > and when he went in he found the coil was *very* dirty (from the
> > crawlspace project) and had to scrape it with cleaning solution.
> > 5) Now, another month later, the problem has returned.
> > I don't know which direction to take this. =A0I don't want to keep bring=

> > techs out who don't fix the root cause (whatever it is). =A0Before I
> > invest in another call, perhaps someone could tell me:
> > - Could this problem really be caused by a defective stat or dirty
> > coil? =A0The stat HAS been loose and the coil HAS been dirty, but the
> > error codes don't mention these, and don't seem to allude to them.
> > For that matter, if the ignition is locked out, will it cause the stat
> > to act funky when I use it? =A0I don't want to pay for another scraping,=

> > or a new coil, if I don't have to.
> > - If I call the techs back, after I make sure they are aware of the
> > codes, what directions should I give them?
> > - Is there anything I can check on my own fairly easily before
> > resorting to another callback?
> > Thanks for any advice,
> > -Larry

> Larry;
> 1. =A0The furnace has been subjected to abuse. =A0[Hence the dirty coil ca=

> the heating unit to 'overheat.'] =A0Change your filter more often, tighten=

> any return air duct leakage, and that wouldn't have happened. =A0Have more=

> annual inspections [as opposed to having a tech only look when there "is" =

> problem in the future.]
> 2. =A0Your ignition lock out is from flame proving failure. =A0Likely the =

> sensor has become fouled and needs a replacement [like a $15 part or less.=

> 3. =A0It's likely from reading your story that you will experience other
> problems as well. It is *unlikely* you have a failed firebox [heat
> exchanger] since the fusible link [provided by the mfg.] hasn't failed or
> there hasn't been a flame rollout event 'yet.' =A0[Depending on model.] =

> because of the abuse from the past, it's likely you have a clogged indoor
> blower motor and clogged blower as well, [evident since the evaporator coi=

> was clogged.] =A0So look forward to a indoor motor replacement soon.
> 4. =A0It's likely you have some supply / return duct repair ahead as well,=

> there was some crawl space work, generally speaking, other trades tend to
> not respect ductwork like you'd think they should.
> --
> Zyp- Hide quoted text -
> - Show quoted text -

>> ltravi...@gmail.com wrote:

>>> Hi all,
>>> Got a furnace problem that has me running in circles. Perhaps some
>>> quick advice can point me in the right direction at least. We have a
>>> Carrier furnace, older that 5 years old, and this year is has been
>>> failing to ignite, flashing error code 14 (ignition lockout) causing
>>> it to wait 3 hours before the next attempt. FYI here is the code
>>> legend:
>>> #14 default= ignition lockout, control will reset after 3 hours.
>>> Refer to #34.
>>> #34 default= ignition proving fault. Check for gas valve turned off,
>>> oxide build up on flame sensor, main shut valve turned off, Green
>>> wire must be connected to furnace sheet metal, proper flame sense
>>> microamps (.5 micro amps DC minimum), inadequit flame carry over or
>>> rough ignition, low inlet gas pressure.
>>> Now, a little history:
>>> 1) Four years ago we had a crawlspace dug out and the project and
>>> the project went poorly, causing the basement to be exposed to
>>> excessive dust and moisture for much of that winter.
>>> 2) This winter we began having trouble with the thermostat. The
>>> backlight would not light, it would display gibberish, and sometimes
>>> not display anything. Shortly thereafter we noticed that this
>>> behavior happened at the same time the furnace had the ignition
>>> lockout.
>>> 3) We called an independent contractor and described the problems.
>>> The tech wasn't aware or (or wasn't concerned with) the codes and
>>> was only concerned with the thermostat. He indeed found and
>>> straightened some bent pins and we could notice a tighter fit when
>>> we closed the cover of the stat. He figured that solved the
>>> problem, and he never even looked at the furnace itself.
>>> 4) A month later the lockout recurred, and the contractor sent
>>> another guy on the callback. The furnace had restarted by then so
>>> he didn't see the codes, and I don't think we mentioned them when
>>> we made the emergency call. Anyway, he was certain it was an
>>> overheating issue and when he went in he found the coil was *very*
>>> dirty (from the crawlspace project) and had to scrape it with
>>> cleaning solution. 5) Now, another month later, the problem has
>>> returned.
>>> I don't know which direction to take this. I don't want to keep
>>> bring techs out who don't fix the root cause (whatever it is).
>>> Before I invest in another call, perhaps someone could tell me:
>>> - Could this problem really be caused by a defective stat or dirty
>>> coil? The stat HAS been loose and the coil HAS been dirty, but the
>>> error codes don't mention these, and don't seem to allude to them.
>>> For that matter, if the ignition is locked out, will it cause the
>>> stat to act funky when I use it? I don't want to pay for another
>>> scraping, or a new coil, if I don't have to.
>>> - If I call the techs back, after I make sure they are aware of the
>>> codes, what directions should I give them?
>>> - Is there anything I can check on my own fairly easily before
>>> resorting to another callback?
>>> Thanks for any advice,
>>> -Larry

>> Larry;
>> 1. The furnace has been subjected to abuse. [Hence the dirty coil
>> causes the heating unit to 'overheat.'] Change your filter more
>> often, tighten up any return air duct leakage, and that wouldn't
>> have happened. Have more annual inspections [as opposed to having a
>> tech only look when there "is" a problem in the future.]
>> 2. Your ignition lock out is from flame proving failure. Likely the
>> flame sensor has become fouled and needs a replacement [like a $15
>> part or less.]
>> 3. It's likely from reading your story that you will experience other
>> problems as well. It is *unlikely* you have a failed firebox [heat
>> exchanger] since the fusible link [provided by the mfg.] hasn't
>> failed or there hasn't been a flame rollout event 'yet.' [Depending
>> on model.] But because of the abuse from the past, it's likely you
>> have a clogged indoor blower motor and clogged blower as well,
>> [evident since the evaporator coil was clogged.] So look forward to
>> a indoor motor replacement soon.
>> 4. It's likely you have some supply / return duct repair ahead as
>> well, if there was some crawl space work, generally speaking, other
>> trades tend to not respect ductwork like you'd think they should.
>> --
>> Zyp- Hide quoted text -
>> - Show quoted text -

> Thanks for the advice Zyp. Indeed I make no excuses for the neglect
> the furnace has had, and accept the consequences. I will replace the
> sensor immediately and have an inspection done since the cooling
> season is not far away. One last question: why does my thermostat
> acting the way it does? When there is a lockout, does the furnace
> send a corrupt control signal to it and cause its display to go
> haywire or is the thermostat poor and cannot interpret what the
> furnace is trying to tell it?
> thanks again,
> Larry