conversion from LP to Nat Gas

[John Dirks Jr]

Hi Gents,

I picked up a cast iron free standing vented fireplace that I want to use for a porch enclosure project.  Empire Comfort Systems CIBV-30-20 

  https://www.manualslib.com/manual/47436/Empire-Comfort-Systems-Pmn.html?page=22#manual

It's currently setup for LP and I want to convert it to Nat Gas.  What are the chances I can get away with drilling the burner orifice and pilot orifice?   With a little luck, might this get the job done?   Tracking down a conversion kit for this thing has been a bit challenging.   

[Bill Kibbel]

Did you try contacting Empire Comfort? (Empire Stove Co.) I'm pretty sure they're still around.

Also contact Northern Propane Products.  I got some gas light parts there - not the right brand, but it worked.

 

[John Dirks Jr]

I could see those two suppliers online but verifying if parts were exactly what I needed was questionable.  I'll contact them by phone and see if I have better luck that way.

Thanks

[Les]

Hey John, I agree with Bill, but would have no problem broaching the orifice.  You know what I learned from your post?  I spell orifice wrong 99% of the time!

 

[John Dirks Jr]

I called Northern Propane.  The gal on the phone was very helpful.  I gave her the model number and she said she'll make a call and get back to me.  She got back to me in about 5 minutes.  Although Empire does not currently stock the kit I want for that model, they are making one for me.  Orifices, parts to modify the gas valve and written instructions are on the way.   $86   I'm happy because the instructions for installation and flame adjustment will be helpful I think.

[John Dirks Jr]

Here is the flame on the stove after being converted from LPG to NG.  This is the lowest setting and it’s still too hot in my opinion.  
 

The instructions for the conversion kit mention adjusting the air shutter but this unit has no such adjustment capability, at least not the way the instructions describe.  Also the manual for this model fireplace says the flame should be more orange, and not blue.  
 
If this burner has no air shutter adjustment , how do I make the flame more orange?  Incidentally, I think an orange flame will be cooler.  
 
If they gave me an orifice that is too large, could that make the flame blue?  What about my gas line pressure, could that be the problem?

Do you have any suggestions which might help me adjust this flame to a more orange color like the manual says it should be?  I want to make it look more natural, and hopefully cool it down just a little.  
 

thanks

[Jim Katen]

That looks like a nicely balanced gas flame. Perhaps when you put the ceramic logs in place, the flames will cool as they impinge on the ceramic? 

[John Dirks Jr]

Yes it does look nice for maximum combustion and efficiency.  But the ambiance is lacking and it gets hotter than it should, even on the low setting.  When the logs are on, the shape of the flames change but they still stay blue, with a tiny tip of orange.  

[John Dirks Jr]

The draft hood is 6” from the gypsum wallboard which is more than compliant with clearance to combustibles listed for this unit.  Even then, the wall temp gets to 160 degrees.   That’s borderline right?

[John Dirks Jr]

Top of the draft hood where the vent pipe connects is in the 350 degree range. 

[Marc]

Reduce the gas pressure maybe?  It's how I control the heat when I'm boiling crawfish on an outside burner.

[John Kogel]

Hello John. Maybe you need less gas pressure with more air to get the yellow flame.

[John Dirks Jr]

Whats the effect differences between changing the gas pressure and actual volume being delivered to the burner?  I assume a smaller orifice would not reduce pressure, but it would reduce volume.  Am I right?
 

About the valve under the stove that raises and lowers the flame. Is it changing pressure or volume to accomplish this?

[Marc]

The orifice influences air/fuel ratio. The pressure influences the size of the fire.

Edited October 18, 2019 by Marc

[John Dirks Jr]

Do you think if I reduce the orifice size the flame will move toward the orange color?  I see no installed method for increasing or decreasing air to the burner.  It’s manufactured without adjustable air shutter.  

[Jim Katen]

10 hours ago, John Dirks Jr said:

Whats the effect differences between changing the gas pressure and actual volume being delivered to the burner?  I assume a smaller orifice would not reduce pressure, but it would reduce volume.  Am I right?

I don't know much about fluid dynamics, but it seems to me that you want to have a way to "dial in" the flame, not make incremental changes. I'd look at installing a needle valve upstream of the burner. 

[BADAIR]

from linked manual

Air Shutter Adjustment

An air shutter adjusting screw is located on the exterior, bottom

of the inner body. Screw air shutter adjusting screw IN to close

air shutter top (increase yellow flame). Screw air shutter adjusting

screw OUT to open air shutter top (decrease yellow flame).

If main burner flame pattern is incorrect, as shown in Figure 19

• See Troubleshooting, page 21

[John Dirks Jr]

46 minutes ago, BADAIR said:

from linked manual

Air Shutter Adjustment

An air shutter adjusting screw is located on the exterior, bottom

of the inner body. Screw air shutter adjusting screw IN to close

air shutter top (increase yellow flame). Screw air shutter adjusting

screw OUT to open air shutter top (decrease yellow flame).

If main burner flame pattern is incorrect, as shown in Figure 19

• See Troubleshooting, page 21

I read that too.  But this unit has no such adjusting screw or air shutter.  When I open it back up I’ll take some more pictures and post them. 

[John Dirks Jr]

On 10/18/2019 at 11:28 PM, Jim Katen said:

I don't know much about fluid dynamics, but it seems to me that you want to have a way to "dial in" the flame, not make incremental changes. I'd look at installing a needle valve upstream of the burner. 

Hi Jim.  This needle valve idea you speak of, I might be giving this a try.  I really think the problem can be solved by cooling the flame.  It’s almost entirely blue now which I know is an efficient burn, and something you would want in a heat exchanger of a furnace.   But in a free standing fireplace which is intended to be ornamental for visual pleasure, the flame should not be fully blue like it is.   As a matter of fact, the operators manual even states such.  It shows a graphic showing “blue flame, incorrect ”. “Yellow flame, correct”.

So, will installation of a needle valve allow me to make the flame yellow, and thus cool it down?   I mean, that’s solving multiple problems.  Cools it down to prevent triggering the high limit from cutting it off and making the flame more yellow for more aesthetic appeal.  

Where exactly within the gas delivery lines would I install such needle valve?  

[Chad Fabry]

To make the flame yellow, you have to have incomplete combustion which means a fuel-rich mixture. 

[John Dirks Jr]

1 hour ago, Chad Fabry said:

To make the flame yellow, you have to have incomplete combustion which means a fuel-rich mixture. 

Ok. If there were an air shutter on this burner, I close it to reduce air and make the mixture richer.  Correct?

There is no air shutter on this burner.  I suppose I can try and fabricate an air shutter of sorts to limit air into the end of the burner.  

[John Dirks Jr]

Actually this flame looks ok I think.  It gets more yellow to it after it’s going for a while.  
 

By checking with my FLIR thermal cam I can tell the temp at the face of the ECO limit switch.  I checked and waited nearby until the stove cut of.  Take temp at switch and it’s 190 degrees.  I think this is supposed to be 350 degree limit switch by the numbers on it.  So it shouldn’t cut out at 190 right?   I’m gonna order a new one and see what happens. 

[John Dirks Jr]

Apparently it’s not the ECO switch cutting the gas valve.  It’s the thermopile.   mv output too low.  I got on this trail after trying to lite the pilot this last time around.  I couldn’t keep it lit.  Checked thermopile voltage and it’s at least 150 mv low. 

[John Dirks Jr]

I got a thermopile for $10 on amazon and put it in.  The mv output was better than my original part but I still could not get the pilot to stay on.  More troubleshooting and I discovered the wire connector for the vent safety switch connection at the back of the gas valve was bad.  Some soldering and a new shrink wrap and we're in business.

 

[ejager]

This has been a most enlightening thread! Glad you got it working!