# Gas Control Valve



## Avant

My fireplace wont light.  I flip the switch and I am getting a spark but doesn't seem like there is any gas coming out.  I am pretty sure the control valve is dead.  It didn't work when we bought the house. 

I can't seem to find this exact part.  I find some that are similar but they all say 3.3" and mine says 3.5".  I am not sure the size makes a difference. 

attached is a picture of the control valve.  Can I just replace with the 3.3" or any others?  Thanks!


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## nealtw

I would think the specs on the label is all you need to match.


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## nealtw

https://www.robertshaw.com/Products/Heating/Gas-Valves/700-048/?cat=2147484264


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## frodo

most likely,  in all probability,  you have air in the line.

try this

turn on gas valve with the key provided....the valve should be with in 3'  of the fire box





 now.... push the button that says  "pilot"   hold it in..
at the same time, touch a flame to the pilot 





at first,  nothing will light, air is in the line,,
when the pilot lights up...release the button, turn the button to "ON"

you can now  turn it off, and use the ignighter button


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## Avant

I do not have a traditional gas valve where you can use the key.  

When I pop the bottom off I have a Gas line where I can shut off the gas with a inline lever.

Then on the gas valve it self there is a hole that says "pilot" but there is nothing in the actual hole.  It is just metal with no opening.  There is no pilot button to press or anything. 

I am getting a constant spark when I flip the switch, just no gas coming out to ignite.


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## nealtw

Avant said:


> I do not have a traditional gas valve where you can use the key.
> 
> When I pop the bottom off I have a Gas line where I can shut off the gas with a inline lever.
> 
> Then on the gas valve it self there is a hole that says "pilot" but there is nothing in the actual hole.  It is just metal with no opening.  There is no pilot button to press or anything.
> 
> I am getting a constant spark when I flip the switch, just no gas coming out to ignite.



found this might help with some tests but is for a unit with pilot.
[ame]https://www.youtube.com/watch?v=P_yoGKqFjOo[/ame]


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## Avant

Yea, My valve only has a on and off switch.  no thermocouple also. There was a screw that I took out and confirmed that gas is being feed to the valve, it just is not "turning on" to allow gas to go out to the fireplace.  So I am pretty sure the valve might be done. 

It could have air in the system but not a clue how to purge this one as there are no thermo or anything else.


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## Avant

Also, does it have to be 3.5"?  I found plenty of 3.3" that match all the other specs.


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## nealtw

Series Application Universal Model 
Factory Part Number 7000DERHC 
Pressure Regulation 3.5" WC Natural Gas 
Capacity 720,000 BTU 
Inlet Size 1" 
Electrical Rating 24V AC @ 60 Hz 
Comments High Capacity 
Outlet Size 1" 
Maximum Inlet Pressure 14" WC (1/2 PSI) 
this is from the site I posted above


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## Avant

Yep, those specs all match up.  Didn't think they were so much money.  Saw some for a bit cheaper but they were 3.3"


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## nealtw

I don't know enough about them to comment any further.:hide:


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## Avant

nealtw said:


> I don't know enough about them to comment any further.:hide:


I am in the same boat!  Hahaha


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## Avant

Turns out my valve is too old and they do not make it.  Found a replacement valve and will be here Friday.

Nealtw, 

As always, thanks for the help!


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## nealtw

Hope it works. wish I know more or someone else that knew more had showed up.


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## frodo

will you post a picture of he piping,  i want to see the valve,  and pilot light 

have you removed the regulator and Verified  gas to unit ?


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## Avant

frodo said:


> will you post a picture of he piping,  i want to see the valve,  and pilot light
> 
> have you removed the regulator and Verified  gas to unit ?



Yep, there is gas getting to the valve.  I confirmed that.  There was a vent screw i pulled out and when opening the gas line it actually comes out of the gas valve.  

The gas shut off valve is just a red lever inline on the gas line.

There is no pilot light at all on this system.  You flip a switch on the wall and the system provides a spark (like a taser)   So no pilot light.


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## frodo

os it have a little door on the burner rod

that is to adjust air fuel mix, 


the new log lighter installed,  is it natural gas or propane.

the orafice is inside where that door is


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## Avant

So i got a new valve.  it fires up but then shuts off after a few seconds.  the ignition module sales "ignition lockout"  I am guessing a bad electrode?


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## frodo

The lockout feature shuts off all gas at the valve should pilot ignition fail to occur after a period of 60 seconds

since you do not have a pilot ,,,the valve is saying the pilot is not lite.a safety feature, it is shutting the valve off.

you either need to install a pilot
or bypass the safety feature
or get a valve with out the lock out

what is the name brand of the valve and the part number


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## nealtw

thermocouple tells the control the you have a flame


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## Avant

The valve is a :
1/2" X 1/2" 24v Direct Spark Gas Valve (170,000 BTU)
SKU: 722-051Brand: Robertshaw

It ignites and flame goes for about 5 seconds then the lock out happens. 

The part that actually sparks (like a taser) has the electrode built on it.  

Looks like this.


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## nealtw

You will have a thermopile. he talks about them at 300 on this video.
[ame]https://www.youtube.com/watch?v=dRjX5m0zHUU[/ame]


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## Avant

yea i dont have one anywhere.  just that flame sensor.


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## nealtw

Well it reads the heat and tells the controller to keep supplying gas, does your controller have a place for two wires and did the old one have a place for two wires?


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## Avant

yea it has the wires hooked up.  just measure resistance and it should be .7 or higher. ill do that today.


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## frodo

your thermo coupling may not be in the pilot flame enough

if you would post pictures,  it sure would be a whole lot easier to help.


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## Avant

Here are the images.


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## nealtw

You missing something , I would get in touch with some one like this and see if they can figure out what you need.
https://www.fire-parts.com/collections/thermocouples-thermopiles


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## frodo

Avant said:


> Here are the images.





i do not see anything,,,no picture ame thru   blank page


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## nealtw

frodo said:


> i do not see anything,,,no picture ame thru   blank page



He has a bracket over the plate with holes for the gas. It has the starter like the one in post 21 with the wire attached and that is all, no thermocouple or Thermopile.

There is one screw missing on the bracket so I think He is missing another part to the bracket too.


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## frodo

if you do not have a thermo coupling ,your valve will not work


your pictures did not upload,  i am tired of guessing,   pleas up load pictures.  

or i can not help you


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## nealtw

Something funky about these pictures, These I can see but others I can not. I thought I might re load them but I can not down load them.


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## Avant

frodo said:


> if you do not have a thermo coupling ,your valve will not work
> 
> 
> your pictures did not upload,  i am tired of guessing,   pleas up load pictures.
> 
> or i can not help you



The pictures are up.  Not sure why you can't see them.

It does not have a thermo coupling.  It has a flame sensor.  There is a Fenwal Ignition Control Module.  When the switch is flipped to turn on the fireplace, the ignition module then gives power to the flame sensor/igniter as well as the gas control valve.  The gas control valve then opens and sends gas up to the fire place where the igniter sparks and starts the fire.

The flame sensor should send a signal back to the ignition control module saying "yes there is flame, keep the gas going" but instead the flame shuts off after about 10 seconds.

My guess is that the flame sensor electrode is faulty and is not sending a signal back to the ignition module.  The module is going into lockout mode as a safety as it is not detecting that there is a flame so it shuts the gas valve off.

The screw is missing cause i was in the process of taking the flame sensor out.


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## Avant

Weird, I am uploading the pictures with google photos.  Try them now.


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## nealtw

Avant said:


> Weird, I am uploading the pictures with google photos.  Try them now.



Maybe frodo will see them now I have lost them.


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## Avant




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## Avant

nealtw said:


> Maybe frodo will see them now I have lost them.



Ok uploaded with different client.  Try now.  post above this one should work.


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## nealtw

Avant said:


> The pictures are up.  Not sure why you can't see them.
> 
> It does not have a thermo coupling.  It has a flame sensor.  There is a Fenwal Ignition Control Module.  When the switch is flipped to turn on the fireplace, the ignition module then gives power to the flame sensor/igniter as well as the gas control valve.  The gas control valve then opens and sends gas up to the fire place where the igniter sparks and starts the fire.
> 
> The flame sensor should send a signal back to the ignition control module saying "yes there is flame, keep the gas going" but instead the flame shuts off after about 10 seconds.
> 
> My guess is that the flame sensor electrode is faulty and is not sending a signal back to the ignition module.  The module is going into lockout mode as a safety as it is not detecting that there is a flame so it shuts the gas valve off.
> 
> The screw is missing cause i was in the process of taking the flame sensor out.



Hmm, if I scroll down from where I am posting this I get the photos.

You are calling it a flame sensor, I did not see that, it looked to me you had the same as in post above that you posted.

The flame sensor is the thermopile and it has 2 wires going to the control; valve. All I see is the sparker and ground rod.


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## nealtw

Avant said:


> Ok uploaded with different client.  Try now.  post above this one should work.



Yes that works.


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## Avant

nealtw said:


> Hmm, if I scroll down from where I am posting this I get the photos.
> 
> You are calling it a flame sensor, I did not see that, it looked to me you had the same as in post above that you posted.
> 
> The flame sensor is the thermopile and it has 2 wires going to the control; valve. All I see is the sparker and ground rod.



Yea, this sensor only has the one 12v wire going to it.  No other wire that goes back to the ignition module.


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## nealtw

Avant said:


> Yea, this sensor only has the one 12v wire going to it.  No other wire that goes back to the ignition module.



That not a sensor , it is just a spark plug.
Does this fireplace have a name model number or anything. when was the house built.


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## Avant

House was built in 1997.  Not sure the brand of fireplace. 

Found the Schematic. I am missing what looks like a ground from that "spark plug" back to the module






But mine is wired like this.


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## nealtw

Avant said:


> House was built in 1997.  Not sure the brand of fireplace.
> 
> Found the Schematic. I am missing what looks like a ground from that "spark plug" back to the module
> 
> 
> 
> 
> 
> But mine is wired like this.



That unit provides the high voltage spark, nothing to do with what you are missing.


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## nealtw

Watch this again and pay attention when he gets to the thermopile. The heat of the fire produces some mini volts and tells the controller to stay open. That is what you haven't got.
[ame]https://www.youtube.com/watch?v=dRjX5m0zHUU[/ame]


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## Avant

Totally get what it does.  Just don't see any place that it would plug/screw into on the gas valve or module.


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## Avant

Found my fire place.  FMIDVF36. 

Here is how it is wired.


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## nealtw

give these guys a call or send them the pictures
http://www.fmiproducts.com/


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## Avant

Ok. I just fixed this stupid thing.  Took the flame sensor out.  Cleaned it.  Then also disconnected the ignition module for a few minutes to clear the ingition lockout code.  Plugged it all back and and BOOM.  Works like a charm now!

Thanks all for the help!  Its working great now!


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## Snoonyb

And they say, housekeeping is a lost art.


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## frodo

do you see a difference in the flame placement here

adjust the sensor to be in the flame more


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## nealtw

Avant said:


> Ok. I just fixed this stupid thing.  Took the flame sensor out.  Cleaned it.  Then also disconnected the ignition module for a few minutes to clear the ingition lockout code.  Plugged it all back and and BOOM.  Works like a charm now!
> 
> Thanks all for the help!  Its working great now!



Good for you, I guess I was going the wrong direction.


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## Avant

No worries.  Just glad people are here to help. 

Next project is my 500Sq ft putting green in the back yard


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## nealtw

Avant said:


> No worries.  Just glad people are here to help.
> 
> Next project is my 500Sq ft putting green in the back yard



Green side up, feed it lots of beer, it will come up half cut:trophy:


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