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Home > Archive > Heating and air conditioning > February 2006 > Intermittent ignition problem
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Intermittent ignition problem
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| Murdentech 2006-02-11, 10:21 am |
| Been away from this group for about 4 years, ( right after Vicki got
married).... seems you guys have been well entertained in the mean time.
Here is one of those pesky intermittent problems... GMC 80% downflow furnace
with spark to pilot ignition. Pilot always lights immediately, then
sometimes the gas valve fails to open or tries to open unsuccessfully...
(click, click, click) ...sensor seems to not be getting proper signal.
The board, sensor and gas valve have all been replaced... at the suggestion
of the Goodman distributor... ( I know, never ask the counter guys for help.
If they knew they wouldn't be behind the counter). Wires are all good and
tight, control voltage is good, spark and sensor wires are new. Additional
ground wire was installed, etc.
Anyway, the man I work with is 73 years old, been doing HVAC for over 50
years. He has forgotten more than the rest of us will ever know.
I finally went out with him to see the problem and scratch our collective
heads... (no jokes there, Paul).
The wires were not orderly inside the furnace, so I straightened them out,
making sure to separate the spark wire from the sensor wire.
That seemed to have helped the problem quite a bit... will see if it fails
again in the near future.
I am working on the possibility that the high voltage from the spark wire
may have been confusing the signal for the sensor... what do you guys think
of this actually being the culprit??
..... flame away and at least try to keep the sarcasm to reality.
Jeff Murden
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| Bubba 2006-02-11, 12:21 pm |
| Sounds like a "good" one, Jeff. Im guessing the board you replace is
the spark ignition module? Otherwise, it sounds like your are chasing
a "broken wire". Have fun with that. If its an older furnace, replace
the spark ignition wire and sensor wire. Make sure the sensor doesnt
have a crack in the procelain.
If that doesnt work, sell them a damn 90%er. Gas is too high for a
80%er anymore.
Oh yeah, dont forget...........
They need a new digital programmable thermostat (not the cheapo brand)
and a couple of those new fangeled @ductboosters. :-)
(You had to be around for a while to catch that last line)
Bubba
On Sat, 11 Feb 2006 13:37:33 GMT, "Murdentech" <j. murden @ insight
bb.com> wrote:
>Been away from this group for about 4 years, ( right after Vicki got
>married).... seems you guys have been well entertained in the mean time.
>
>
>Here is one of those pesky intermittent problems... GMC 80% downflow furnace
>with spark to pilot ignition. Pilot always lights immediately, then
>sometimes the gas valve fails to open or tries to open unsuccessfully...
>(click, click, click) ...sensor seems to not be getting proper signal.
>
>The board, sensor and gas valve have all been replaced... at the suggestion
>of the Goodman distributor... ( I know, never ask the counter guys for help.
>If they knew they wouldn't be behind the counter). Wires are all good and
>tight, control voltage is good, spark and sensor wires are new. Additional
>ground wire was installed, etc.
>
>Anyway, the man I work with is 73 years old, been doing HVAC for over 50
>years. He has forgotten more than the rest of us will ever know.
>
>I finally went out with him to see the problem and scratch our collective
>heads... (no jokes there, Paul).
>
>The wires were not orderly inside the furnace, so I straightened them out,
>making sure to separate the spark wire from the sensor wire.
>
>That seemed to have helped the problem quite a bit... will see if it fails
>again in the near future.
>
>I am working on the possibility that the high voltage from the spark wire
>may have been confusing the signal for the sensor... what do you guys think
>of this actually being the culprit??
>
>.... flame away and at least try to keep the sarcasm to reality.
>
>
>Jeff Murden
>
| |
| Cooltemp Industries 2006-02-11, 4:21 pm |
|
Murdentech wrote:
> The wires were not orderly inside the furnace, so I straightened them out,
> making sure to separate the spark wire from the sensor wire.
It's always recommended to separate the high tension lead from the
sensor wire.
Make sure the sensing tube from the pressure switch is trimmed so it
goes straight into the ventor, and doesn't form a trap. Moisture build
up in the tube will cause problems.( Most likely not your problem here
because you're getting a pilot, but just something else to be aware of
with the Goodmans.)
Check your ground all the way back to the panel.
If that fails, check for a constant 24 volts at the circuit board when
the valve is chattering. If you've got a steady 24 at the board, and not
at the valve, it's the wire leading to the valve from the board.
| |
|
| On Sat, 11 Feb 2006 13:37:33 GMT, "Murdentech" <j. murden @ insight
bb.com> wrote:
<SNIP>
>
>I am working on the possibility that the high voltage from the spark wire
>may have been confusing the signal for the sensor... what do you guys think
>of this actually being the culprit??
>
On a Protection Controls flame safeguard control, powering the
6,000V end point grounded transformer lead ,running parallel with the
U.V. signal wires (UV wires in its own emt) was causing the flame-pak
relay to pull/chatter in and out with no pilot flame!
This was a separate 1/2" emt for the UV. The silicone IG- wire is
outside of the emt approximately 1/2" apart, going down the wall of
this oven for about 40 ft.
Running another emt for the transformer lead and separating the
emts by 8+ inches stopped this.
Did I mention how much I really dislike Protection Controls?
-zero
| |
|
| Jeff,
One other thing on the Goodman.
Check the port on the inducer motor housing. Sometimes it gets
partially clogged with a whitish calcium buildup. Poke it out with a
wire if it is.
Otherwise, get a @port booster :-)
Bubba
On Sat, 11 Feb 2006 15:31:31 GMT, Bubba <<ReMoVe likealake@iname.com>>
wrote:
[color=darkred]
>Sounds like a "good" one, Jeff. Im guessing the board you replace is
>the spark ignition module? Otherwise, it sounds like your are chasing
>a "broken wire". Have fun with that. If its an older furnace, replace
>the spark ignition wire and sensor wire. Make sure the sensor doesnt
>have a crack in the procelain.
>If that doesnt work, sell them a damn 90%er. Gas is too high for a
>80%er anymore.
>Oh yeah, dont forget...........
>They need a new digital programmable thermostat (not the cheapo brand)
>and a couple of those new fangeled @ductboosters. :-)
>(You had to be around for a while to catch that last line)
>Bubba
>
>On Sat, 11 Feb 2006 13:37:33 GMT, "Murdentech" <j. murden @ insight
>bb.com> wrote:
>
| |
|
| I had an intermittent problem with a GMC unit sometime ago. The Molex
connector from the vestibule area through to the blower compartment was the
culprit. Check and see of corrosion has plagued the pins. Factory
recommended splicing the Molex out of the picture.
Zyp
"Murdentech" <j. murden @ insight bb.com> wrote in message
news:xMlHf.760651$x96.585201@attbi_s72...
> Been away from this group for about 4 years, ( right after Vicki got
> married).... seems you guys have been well entertained in the mean time.
>
>
> Here is one of those pesky intermittent problems... GMC 80% downflow
> furnace with spark to pilot ignition. Pilot always lights immediately,
> then sometimes the gas valve fails to open or tries to open
> unsuccessfully... (click, click, click) ...sensor seems to not be getting
> proper signal.
>
> The board, sensor and gas valve have all been replaced... at the
> suggestion of the Goodman distributor... ( I know, never ask the counter
> guys for help. If they knew they wouldn't be behind the counter). Wires
> are all good and tight, control voltage is good, spark and sensor wires
> are new. Additional ground wire was installed, etc.
>
> Anyway, the man I work with is 73 years old, been doing HVAC for over 50
> years. He has forgotten more than the rest of us will ever know.
>
> I finally went out with him to see the problem and scratch our collective
> heads... (no jokes there, Paul).
>
> The wires were not orderly inside the furnace, so I straightened them out,
> making sure to separate the spark wire from the sensor wire.
>
> That seemed to have helped the problem quite a bit... will see if it fails
> again in the near future.
>
> I am working on the possibility that the high voltage from the spark wire
> may have been confusing the signal for the sensor... what do you guys
> think of this actually being the culprit??
>
> .... flame away and at least try to keep the sarcasm to reality.
>
>
> Jeff Murden
>
>
| |
| Cooltemp Industries 2006-02-11, 8:21 pm |
|
Zyp wrote:
> I had an intermittent problem with a GMC unit sometime ago. The Molex
> connector from the vestibule area through to the blower compartment was the
> culprit. Check and see of corrosion has plagued the pins. Factory
> recommended splicing the Molex out of the picture.
Me too.
I kept losing the 110.
One of the pins had partially pushed back out of the connector, instead
of mating with the incoming pin. (Ya, I know. It all sounds kinda'
porno! ) LOL
| |
| B-Hate-Me 2006-02-12, 8:21 am |
| Murdentech wrote:
> Been away from this group for about 4 years, ( right after Vicki got
> married).... seems you guys have been well entertained in the mean time.
>
>
> Here is one of those pesky intermittent problems... GMC 80% downflow furnace
> with spark to pilot ignition. Pilot always lights immediately, then
> sometimes the gas valve fails to open or tries to open unsuccessfully...
> (click, click, click) ...sensor seems to not be getting proper signal.
Is it a flame sensor or does it rectify or both?
| |
| Murdentech 2006-02-12, 9:21 am |
|
"B-Hate-Me" <trickdaddy@email.com> wrote in message
news:w5KdnVoogbsdvHLeRVn-vg@comcast.com...
> Murdentech wrote:
[color=darkred]
> Is it a flame sensor or does it rectify or both?
Well sir, I don't rightly know... the unit uses a standard 90 second trial
spark module to light the pilot, once the sensor sees pilot it opens up the
gas valve. Spark is continuous until pilot is established and proven, then
spark stops and main valve opens.
Typical setup with PV, MV and COM to control primary and secondary.
Frankly, Rectify is word I haven't heard in a while... refreshment would be
appreciated.
Jeff
| |
| Cooltemp Industries 2006-02-12, 1:21 pm |
|
Murdentech wrote:
> Frankly, Rectify is word I haven't heard in a while... refreshment would be
> appreciated.
An AC voltage is applied by the ignitor. A flame will conduct
electricity, but not very well. Consequently, voltage flows mostly in
one direction, from the ignitor to the flame sensor, but not back, hence
the term rectified, essentially a DC amperage. The sensor detects an
extremley low amperage, in millionths of an ampere, or microamps.
That's how it was explained to me.
If I'm wrong, I'm sure I'll hear about it! LOL
| |
| .p.jm@see_my_sig_for_address.com 2006-02-12, 1:21 pm |
| On Sun, 12 Mar 2006 11:46:38 -0500, Cooltemp Industries
<gbroderick@sunlife.com> wrote:
>
>
>Murdentech wrote:
>
>
>
>An AC voltage is applied by the ignitor. A flame will conduct
>electricity, but not very well. Consequently, voltage flows mostly in
>one direction, from the ignitor to the flame sensor, but not back, hence
>the term rectified, essentially a DC amperage. The sensor detects an
>extremley low amperage, in millionths of an ampere, or microamps.
>That's how it was explained to me.
>If I'm wrong, I'm sure I'll hear about it! LOL
Hey !
Hey now !!!!!
Take this shit to alt.hvac !!!!!!
Ummm.... wait a minute .....
Nevermind.
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| Murdentech 2006-02-12, 4:21 pm |
|
"Cooltemp Industries" <gbroderick@sunlife.com> wrote in message
news:4414506E.9040703@sunlife.com...
>
>
> Murdentech wrote:
>
>
>
> An AC voltage is applied by the ignitor. A flame will conduct electricity,
> but not very well. Consequently, voltage flows mostly in one direction,
> from the ignitor to the flame sensor, but not back, hence the term
> rectified, essentially a DC amperage. The sensor detects an extremley low
> amperage, in millionths of an ampere, or microamps.
> That's how it was explained to me.
> If I'm wrong, I'm sure I'll hear about it! LOL
>
Makes sense as you described it... the voltage is thus rectified by the
flame. On the system in question it is a simple spark module, don't know it
there is rectification or not, but will talk to Dick Dugdeon about this and
share the thought....
Seems logical as I've always wondered how a simple sensor gets it's
millivolt signal, unlike a thermocouple that generates it's own.
Hasn't failed in the past two days since I separated the High voltage wire
and sensor wire.
Jeff
| |
| gofish@gonefishin.net 2006-02-13, 12:21 am |
| "Murdentech" wrote:
>
>"Cooltemp Industries" <gbroderick@sunlife.com> wrote in message
>news:4414506E.9040703@sunlife.com...
>
>Makes sense as you described it... the voltage is thus rectified by the
>flame. On the system in question it is a simple spark module, don't know it
>there is rectification or not, but will talk to Dick Dugdeon about this and
>share the thought....
>
>Seems logical as I've always wondered how a simple sensor gets it's
>millivolt signal, unlike a thermocouple that generates it's own.
>
>Hasn't failed in the past two days since I separated the High voltage wire
>and sensor wire.
>
>Jeff
>
>
there's others, this is a nice place to start.
http://tinyurl.com/5ewvm
| |
|
| A most recent development - is the natural gas supplied from Oklahoma /
Texas wells tend to have a considerable amount of sulfur. Apparently even
after scrubbing the gas by the utility to remove sulfur, enough sulfur
collects on the sensor to interfere with flame rectification. You can clean
using oxide sandcloth, but doing so tends to remove a protective coating the
Mfg. placed on the sensor. Usually it is recommended to replace the sensor
if that's the problem. But in a pinch, sanding works.
Zyp
<gofish@gonefishin.net> wrote in message
news:nf00v1t6190iet0vqtpbskd1of9d97t247@4ax.com...
> "Murdentech" wrote:
>
>
> there's others, this is a nice place to start.
>
> http://tinyurl.com/5ewvm
| |
| Tekkie® 2006-02-13, 8:21 pm |
| posted for all of us...
I don't top post - see either inline or at bottom.
> On Sun, 12 Mar 2006 11:46:38 -0500, Cooltemp Industries
> <gbroderick@sunlife.com> wrote:
>
>
> Hey !
>
> Hey now !!!!!
>
> Take this shit to alt.hvac !!!!!!
>
> Ummm.... wait a minute .....
>
>
> Nevermind.
>
>
>
>
I wuz startn to catch on when they said rectumfried
--
My boss said I was dumb and apathetic.
I said I don't know and I don't care...
Tekkie
| |
| Tekkie® 2006-02-13, 8:21 pm |
| Zyp posted for all of us...
I don't top post - see either inline or at bottom.
> A most recent development - is the natural gas supplied from Oklahoma /
> Texas wells tend to have a considerable amount of sulfur. Apparently even
> after scrubbing the gas by the utility to remove sulfur, enough sulfur
> collects on the sensor to interfere with flame rectification. You can clean
> using oxide sandcloth, but doing so tends to remove a protective coating the
> Mfg. placed on the sensor. Usually it is recommended to replace the sensor
> if that's the problem. But in a pinch, sanding works.
>
> Zyp
>
> <gofish@gonefishin.net> wrote in message
> news:nf00v1t6190iet0vqtpbskd1of9d97t247@4ax.com...
>
>
>
And I just thought it was that beer/egg combo I had...
--
My boss said I was dumb and apathetic.
I said I don't know and I don't care...
Tekkie
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