Goodman gas valve not working

[Naaman]

I have a Goodman GMP100-3 furnace that will not fire up. It's been giving
me problems for a few weeks now but finally quit altogether. Early
symptoms were as follows: Draft induction motor would turn on - after a
few seconds, the HSI would glow - the gas valve would open and the gas
would fully ignite across all four orifices - after 20 seconds or so, the
main blower would turn on and immediately the gas valve would close and
flame would go out - after another 20-30 seconds the HSI would glow, valve
would open, gas ignite and furnace would run it's cycle without occurrence
until the next time the thermostat called for heat.

Later symptoms would be similar to the earlier ones (mentioned above) but
would include the gas valve closing even after the main blower was running
and flame had been burning for several seconds. Now the gas won't ignite
at all, even though I can hear the gas valve click.

After three tries, I got a single flash from the diagnostic LED (ignition
failure). So, I tried cleaning the flame sensor...didn't help - I tried
replacing the flame sensor...didn't help - I tried bypassing all the temp
sensors and connecting the gas valve directly to the control board's
purple wire (removed from 1st temp sensor [in series])...didn't help.

I'm getting 27 AC volts to the gas valve and am hearing the right (output
side of valve) solenoid click when the control board calls for gas.
However, I'm not hearing or feeling the left (inlet side of valve)
solenoid click. Almost seams like a week solenoid. Are both solenoids
supposed to open together? Why are there two solenoids? Is this for
safety....to make sure the valve closes....in case one valve sticks open?
I's there a way to test this valve further?

Any help would be appreciated.

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[Tony Hwang]

Hi,
Checked and cleaned flame sensor? Any trouble code on the control board?
You said valve is not working, I think not. It is shutting down
'coz something is not right in the chain of sequence in operation.

Very likely flame sensor just needs cleaning. Good rubbing with emery
cloth or cotton fabric will do. I think it is first thing to try. Or
the hi limit switch is stuck closed maybe but I doubt it. Check it with
multi meter. If it keeps this up/down cycle few times, it'll lock up. To
reset it turn the power to the furnace off, wait a little bit and turn
it back on. Otherwise it'll be in lock out state for couple hours.

[tra...@optonline.net]

I haven't debugged one of these myself, but it seems like you
have the basics covered. If the gas valve has the proper voltage on
it and the gas isn't flowing, then either it's a bad valve, pipe leading
to it is plugged, etc. It's not a sensor problem.

As to the part about two solenoids on the valve, is this perhaps
a two stage furnace?

[Tony Hwang]

Hi,
If it is 2 stage valve, 'stat can be configured as 1 or 2 stage
operation. For testing configure it as 1 stage and see what happens.
Valve is opening for sure that is why you get flames. It is not staying
open. Again nothing to lose, check and clean flame sensor. Again, no
trouble code?

[Steve]

replying to Naaman, Steve wrote:

Here is a source for the service manual for the Goodman GMP100-3:

http://www.hvacpartsshop.com/Goodman-Service-Manuals.aspx




--

[Naaman]

replying to Tony Hwang , Naaman wrote:

> dragon40 wrote:
>
> Hi,
> If it is 2 stage valve, 'stat can be configured as 1 or 2 stage
> operation. For testing configure it as 1 stage and see what happens.
> Valve is opening for sure that is why you get flames. It is not staying
> open. Again nothing to lose, check and clean flame sensor. Again, no
> trouble code?

It's a one stage valve (only two wires connected to valve [hot & ground])
but it appears to have two solenoids. Already tried cleaning the flame
sensor with steel wool. That didn't help so I replaced the flame sensor.
That didn't help either. The gas valve does click but no gas comes out.
Think I may take the valve apart and see if the passages are clogged. Will
update this thread in a couple days.

--

[Naaman]

replying to tra...@optonline.net , Naaman wrote:

> trader4 wrote:
>
> I haven't debugged one of these myself, but it seems like you
> have the basics covered. If the gas valve has the proper voltage on
> it and the gas isn't flowing, then either it's a bad valve, pipe leading
> to it is plugged, etc. It's not a sensor problem.
> As to the part about two solenoids on the valve, is this perhaps
> a two stage furnace?

Thanks for the reply. Ok, I found out why the one solenoid wasn't opening.
When I bypassed the sensors, I removed the jumper wire that bridged the M1
& P3 terminals, in order to make room for the test wire (circuit board
purple wire to M1 terminal). I then forgot to replace the jumper wire.
After putting the jumper wire back on, the flame is now working. However,
I'm still having the original problem of the gas valve closing about 3-5
seconds after the HSI turns off. I did clean the flame sensor and also
replaced it with a new one. I am getting 27 volts to the valve while the
valve is open and zero volts after it closes. So, it appears that the gas
valve is working properly but not sure why I'm loosing the 27 volts. After
3 cycles/tries, I'm getting a single flash on the circuit board, which
indicates "Ignition Failure". Maybe my new flame sensor is defective? I
may take it back, exchange it and try again.

--

[Naaman]

replying to Tony Hwang , Naaman wrote:
> dragon40 wrote:
>

> Hi,
> If it is 2 stage valve, 'stat can be configured as 1 or 2 stage
> operation. For testing configure it as 1 stage and see what happens.
> Valve is opening for sure that is why you get flames. It is not staying
> open. Again nothing to lose, check and clean flame sensor. Again, no
> trouble code?

I did clean and finally replace the flame sensor. Valve still keeps
shutting off 3-5 seconds after HSI shuts off. I think I will return the
flame sensor and exchange it for another one. Thanks

--

[Tony Hwang]

Hi,
Sensor has very low o/p voltage, lot less than a volt. meter with mV or
miro volt range will see the o/p. Or 'scope.

[Tony Hwang]

Hmm,
Two sensor can't be bad. Sensor circuit may be. Or other safety feature
is shutting it down. There is a air pressure sensor monitoring draft
motor blower. Did you check this guy? Some times loose dirt flopping
up/down plugs up that plastic tubing.

[Naaman]

replying to Tony Hwang , Naaman wrote:
> dragon40 wrote:
>

> Hi,
> Checked and cleaned flame sensor? Any trouble code on the control board?
> You said valve is not working, I think not. It is shutting down
> 'coz something is not right in the chain of sequence in operation.
> Very likely flame sensor just needs cleaning. Good rubbing with emery
> cloth or cotton fabric will do. I think it is first thing to try. Or
> the hi limit switch is stuck closed maybe but I doubt it. Check it with
> multi meter. If it keeps this up/down cycle few times, it'll lock up. To
> reset it turn the power to the furnace off, wait a little bit and turn
> it back on. Otherwise it'll be in lock out state for couple hours.

As mentioned in my original post, I did clean and finally replace the
flame sensor. However, while installing the new sensor, my screws did
strip out when tightening them. Does this need a good connection (good
ground) to it's mounting surface? The flame sensor is slightly loose.

--

[Tony Hwang]

Hi,
Sure just like a thermocouple. Dealing with very low voltage(current)

[CRNG]

On Thu, 28 Nov 2013 19:44:02 +0000, Naaman
<caedfaa9ed1216d60e...@example.com> wrote in
<1667d$52979d02$cf3aab60$21...@news.flashnewsgroups.com> Re Goodman
gas valve not working:

>I have a Goodman GMP100-3 furnace that will not fire up. It's been giving
>me problems for a few weeks now but finally quit altogether. Early
>symptoms were as follows: Draft induction motor would turn on - after a
>few seconds, the HSI would glow - the gas valve would open and the gas
>would fully ignite across all four orifices - after 20 seconds or so, the
>main blower would turn on and immediately the gas valve would close and
>flame would go out - after another 20-30 seconds the HSI would glow, valve
>would open, gas ignite and furnace would run it's cycle without occurrence
>until the next time the thermostat called for heat.

Sounds like you may have a leak in your flame-tube (fire) box. This
is where the gas burns. Outside the flame tubes is where the air
flows, picking up the heat and bringing into the house distribution
ducts. There are sensors to detect leaks. Leaks would allow gas and
combustion products to leak into the ducts, so if a sensor thinks
there is a leak, it shuts the gas. If your unit is more than 10 year
old, this may be the problem.
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[tra...@optonline.net]

Why do you have him screwing with sensors, when he says he gets
voltage on the gas valve, it clicks, but no gas? That is not a sensor
problem. It's a problem with the gas valve, or blockage in the gas
line, etc.

[tra...@optonline.net]

Good grief. You had voltage at the gas valve. You heard it click, but
gas doesn't come out. That isn't a sensor problem. I suggest you get
a pro in.

[tra...@optonline.net]

On Thursday, November 28, 2013 11:19:04 PM UTC-5, Tony Hwang wrote:
> Naaman wrote:
>
> > replying to tra...@optonline.net , Naaman wrote:
>
> >> trader4 wrote:
>
> >>
>
> >> I haven't debugged one of these myself, but it seems like you have the
>
> >> basics covered. If the gas valve has the proper voltage on it and the
>
> >> gas isn't flowing, then either it's a bad valve, pipe leading to it is
>
> >> plugged, etc. It's not a sensor problem. As to the part about two
>
> >> solenoids on the valve, is this perhaps a two stage furnace?
>
> >
>
> >
>
> > Thanks for the reply. Ok, I found out why the one solenoid wasn't opening.
>
> > When I bypassed the sensors, I removed the jumper wire that bridged the M1
>
> > & P3 terminals, in order to make room for the test wire (circuit board
>
> > purple wire to M1 terminal). I then forgot to replace the jumper wire.
>
> > After putting the jumper wire back on, the flame is now working. However,
>
> > I'm still having the original problem of the gas valve closing about 3-5
>
> > seconds after the HSI turns off. I did clean the flame sensor and also
>
> > replaced it with a new one. I am getting 27 volts to the valve while the
>
> > valve is open and zero volts after it closes. So, it appears that the gas
>
> > valve is working properly but not sure why I'm loosing the 27 volts. After
>
> > 3 cycles/tries, I'm getting a single flash on the circuit board, which
>
> > indicates "Ignition Failure". Maybe my new flame sensor is defective? I
>
> > may take it back, exchange it and try again.
>
> >
>

Based on the new info, I agree it now looks like a sensor
or control issue.

> Hmm,
>
> Two sensor can't be bad.

Seems very unlikely.

Sensor circuit may be. Or other safety feature
>
> is shutting it down. There is a air pressure sensor monitoring draft
>
> motor blower. Did you check this guy? Some times loose dirt flopping
>
> up/down plugs up that plastic tubing.

That could be a possibility. He really needs a circuit diagram
to see what sensors are involved. Checking the vent pipes for
obstructions would be a simple thing to check too.

[bud--]

The service instructions, from Steve's post, appear to be:
http://www.hvacpartsshop.com/Gmph075-4%20Series.Pdf
You may already have them

According to the instructions 1 flash indicates "ignition failure",
which you said, with causes of
gas flow
gas pressure
gas valve
flame sensor

Since the burner lights, the gas related items shouldn't be the problem.

The flame rod needs to be in the flame. I think you want the outer cone
of the flame. With a loose mounting the rod could be out of position.

The flame needs to contact the burner - it can't lift off of the burner.

The instructions have a test for the flame sensor using a microameter,
reading a few microamps. This is a very low current, you may not have a
meter that measures that low. The flame rod likely uses "flame
rectification" - if ac is applied the current is higher in one direction.

If the flame current is in the specified range the controller is likely
the problem.

I didn't look at the circuit - don't know what other sensors are there
(like flame roll-out). Some of the other Goodman models will tell you
what sensor causes a failure - don't know about yours.

[mako...@yahoo.com]

>
> I didn't look at the circuit - don't know what other sensors are there
>
> (like flame roll-out). Some of the other Goodman models will tell you
>
> what sensor causes a failure - don't know about yours.

some flame sensor circuits need the furnace to be well grounded electrically because the circuit through the flame completes to the ground.

make sure your power feed ground is good and that the hot (black) and neutral (white) power wires are not reversed someplace.


Mark

[mako...@yahoo.com]

but on the on the hand, if the unit always trips off only AFTER THE BLOWER starts, then you might have a problem like rollout that one of the other sensors is tripping off

Mark

[Naaman]

replying to bud-- , Naaman wrote:

> null wrote:
>
> The service instructions, from Steve's post, appear to be:
> http://www.hvacpartsshop.com/Gmph075-4%20Series.Pdf
> You may already have them
> According to the instructions 1 flash indicates "ignition failure",
> which you said, with causes of
> gas flow
> gas pressure
> gas valve
> flame sensor
> Since the burner lights, the gas related items shouldn't be the problem.
> The flame rod needs to be in the flame. I think you want the outer cone
> of the flame. With a loose mounting the rod could be out of position.
> The flame needs to contact the burner - it can't lift off of the burner.
> The instructions have a test for the flame sensor using a microameter,
> reading a few microamps. This is a very low current, you may not have a
> meter that measures that low. The flame rod likely uses "flame
> rectification" - if ac is applied the current is higher in one direction.
> If the flame current is in the specified range the controller is likely
> the problem.
> I didn't look at the circuit - don't know what other sensors are there
> (like flame roll-out). Some of the other Goodman models will tell you
> what sensor causes a failure - don't know about yours.

It's WORKING!!! :-D After installing larger screws to fix the loose flame
sensor, I tested the sensor with the volt meter. I got zero micro-amps. So
I picked up a new control board, installed it and retested. I now have 3-4
micro-amps. Re-connected the flame sensor wire and fired it up. It's been
running for over 30 minutes now without a hitch. Thanks to everyone that
contributed your input. It would have been another cold night had I not
gotten help with this. Much appreciated! :-)

--

[Naaman]

replying to makolber , Naaman wrote:

> makolber wrote:
>
> but on the on the hand, if the unit always trips off only AFTER THE BLOWER
starts, then you might have a problem like rollout that one of the other
sensors is tripping off
> Mark

Thanks, Mark. I think I may have some roll-out now that I am more educated
on this issue. I didn't know that this wasn't normal until now. It looks
like it's been doing this for some time (couple years) now, seeing the
roll-out sensor just above the flame tubes has been bypassed by the
previous home owner. It only appears to be doing this on the third tube
from the left. I have uploaded a video to YouTube and will attach the link
here: http://www.youtube.com/watch?v=VmS0XD-Nojk&feature=em-upload_owner

How dangerous is this? The furnace is in my unfinished basement (concrete
walls & floor) on a concrete slab with nothing near it that could catch
fire. There is a sheet-metal heat shield between the flames and the gas
valve, draft inducer, sensors, etc. so no flames are able to come into
direct contact with anything else in the furnace.

--

[ducksoup1952]

replying to Naaman, ducksoup1952 wrote:
I enjoyed coming across this thread. I'm fighting a similar prob with a
Munchkin 399M-R2. Might be the flame rectification sensor and this is the
least expensive guess.

--
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[Tekkie®]

ducksoup1952 posted for all of us...

Datz nize

--
Tekkie