Weber Summit Too Hot? NG to Propane conversion


 

CJDeeg

New member
Brand new Summit S-670. I just completed the conversion from NG to Propane and fired it up for the first time. There appears to be almost no difference between High and Low.
I replaced the NG regulator with a propane line and regulator. Changed out the orifices on all the the burners (including roti, sear and side burner).


Am missing something here? Is this the nature of the Summit?
 
Where did you get the orifices from? That would seem to be your problem if I had to guess. But, maybe Larry will chime in with his knowledge on the subject.
 
There could be a number of reasons. Going from NG to LP is not always the easiest. Most of the later grills come with a continuously variable valve BUT unless you look at them you don't know for sure. If it has "stepped" or fixed orifice valves you cannot change/convert from NG to LP without complete manifold and valve assemblies. You could have also wrong sized orifices too. I remember the first time I converted a grill IIRC it was a 48k btu grill and stupid me I made the orifices for 48k PER BURNER (I think I was drinking at the time) it was a blow torch LOL. So new set of orifices and properly sized and all well.
Odds of your grill having fixed type valves is pretty slim BUT still possible. All depends on which Chinese co Weber sourced them from.
Here is a chart http://andersonforrester.com/conversion-chart/ that will give you reference for the conversion.
You may also have the wrong type of regulator. You can buy high pressure regulators and low pressure types. You need a low pressure type 11"WC.
Good luck sounds like you're gonna need it
 
Thanks LMicaels.

Orifices are not fixed, I swapped the all out, and regulator is low pressure. Did my first cook tonight, skirt steak and kabobs tonight. Came out pretty good. It may be the case that I don't really see a dramatic decrease in the flame hight (as I did with my old Genesis) but the heat seemed manageable.

As I was cooking it off yesterday (to burn out any chemicals/junk that might have come with the grill) i could not get the temperature to adjust down by reducing the burners, but it may just be that I was not patient enough. Running all 6 burners and the sear jacked the heat up very fast. I think I need to do some cooking o see if I actually have an issue here.

Thanks again.
 
Got some coaching from Jason at Grill-Repair. I have been paying with the venting sleeves on the front of the burners. Initially I had an all blue flame. Playing with some tweaks to get the yellow tips. Will see if this allows me to dial back the heat a little.
 
Be careful with that adjustment. Yellow tips are a little misleading. The shutters as they come from the factory should be fine whether on NG or LP as long as the orifices are CORRECT. My guess is with all main burners on low (not sear burner but just the 6) your grill should be able to hold about 350 to 450 *depending on wind and ambient temps" and with all (six only) on high should see 550 to 600. If this is not the case "Jason" is giving you BS and leading you down the wrong path. IN adjusting the shutters forget "yellow tips" and instead look for flames that hold from the surface of the burner without gurgling or breaking up. The PROPER setting is the flames should hold "steady" from the burner surface without blowing away in parts or becoming sooty or yellow. Forget striving for yellow tips as that is actually causing the burn to be too rich in gas. You're trying to achieve Stoichiometric air fuel ratio. Yellow tips may or may not occur. I think you're messing your grill up by not knowing what you're doing and following the lead of someone else who also seems to not know or care
 
Ill check the temp settings and see what I get. I will tell you that high got me closer to 700 -No wind, about 75 degrees.

as far as not knowing, That is exactly why I am here and asking questions.

All orifices changed. Propane regulator installed. I guess I need to confirm that the orifices are the correct size.

I have to say that they the folks at Grill repair have been incredibly responsive, and I get no "don't care" vibe by any means.

As far as adjusting the air flow, on either extreme I do see a radical difference in the flames, but for about 80% of the adjustment, there is minimal difference. I always have steady attachment to the surface in that 80% range. I am tweaking burners side by side so as to get a good comparison.

I have three days with of grilling ahead of me, and I think its entirely possible that I just need to get used to the cook on this grill. It may be that my old low was just a hell of a lot lower then the summit will deliver.
 
Yeah my bad on that top temp. It was the Ambien :D I actually meant to type 600 to 700 depending on air temp and wind conditions. Damn Ambien
 
I just did the same conversion, using the same source for orifices, and am having a similar issue. Shutters need to be all the way open. Is there a way to check the orifice valves to see if they are fixed or stepped. I'll also double check the size of the orifices.
 
I just did the same conversion, using the same source for orifices, and am having a similar issue. Shutters need to be all the way open. Is there a way to check the orifice valves to see if they are fixed or stepped. I'll also double check the size of the orifices.

You should NOT have to touch the shutters. If the gas is being metered in CORRECTLY the factory adjustment should NOT be touched. Grills (anything for that matter) does NOT care what kind of "gas" you "feed" it. All they care is it's the CORRECT AMOUNT at the CORRECT PRESSURE. When those 2 things are NOT met than people who don't know what they're doing either start playing with this or tell you to do so. WRONG WRONG WRONG!!!!!!
When the gas leaves that orifice AGAIN if it is regulated and proportioned CORRECTLY the stoichiometric ratio will be exactly the same! You both are playing with fire here!
 
I like it when "Playing with Fire" can be taken literally.

So are the stoichiometric ratio's for propane and NG close enough that it does not make a difference what the vents are doing? Doesn't the air mix in NG vary, while Propane is pretty consistent?

Is it possible that the factory adjusts the shutters one way for NG and another for Propane?


MarkDM If by stepped, you mean a "chamber" on the underside of the orifice, going to a smaller hole, then yes they are stepped. What was you fix when you experienced the same issue?

I am 100% certain that all the way open is not the option on my grill. both extremes (open and shut) produced poor results.
 
OK first given your description to Mark you have fixed orifice valves not continuous. There is no hard/fast rule with Weber because they buy them from whoever is the cheapest Chinese supplier they can find. So first off a simple orifice change will NOT work correctly. You will need an entire manifold set up for ALL the burners to have this work correctly. Due to the pressure difference between NG/LP as it ENTERS the valve. Once it leaves the orifice it should be fully corrected for in regard to pressure and BTU content and no shutter (carburetor) adjustment should be necessary to achieve a clean and proper burn. So yes once the gas LEAVES that orifice the flow should be corrected for the type and volume of fuel so no adj should be done. If you find yourself needing to make an adj and or the adj makes little to no difference something is definitely wrong. It should not behave that way. The air mix in NG does not vary. More myths from the internet and people who don't know their rear end from a hole in the ground. My guess is first this guy at that store sized those orifices wrong or misunderstood what you need/want, also you have one of the odd grills that Weber used fixed valves on. This is entirely within their purview as long as the valve does the job for which it's intended. Since they really no longer manufacture the grills but simply assemble them from a bunch of foreign parts it really is a crap shoot as to what you get.
Now this is not all bad news here. Once you get the proper flow of fuel past the orifice and set the shutters back to factory (you did mark them didn't you?) the worst case scenario is at full on you will ave proper heat output but little to no regulation from high to low unless you start turning burners off to reduce temps. IT's not "dangerous" per se' but it is VERY inconvenient for some types of cooking. i.e. You're doing a large cookout of say burgers where you want solid and even heat across the entire grill so you might want to be able to say run all 6 burners on med or low to achieve this. You will never be able to achieve it because you will never be able to get the burners to go low enough without fully turning some off leaving hot and cold spots.
The only time the valve issue becomes "dangerous" is when you take it from LP to NG with fixed valves. Than gas flow on med or low could be insufficient to maintain a flame yet gas will still flow and could build up to dangerous levels inside a closed grill causing an explosion (or at best a very large "WHOOSH" of flame) when you open the lid.
So yes you ARE playing with fire. It's not rocket science but it's NOT for amateurs either. I was taught everything I know about it by a licensed gas service engineer. So I learned quite a lot. Just doing my best to impart that knowledge and share
 
If I ever need to do a NG to LP or vice versa, I am just going to find a donor manifold and be done with it. All these Stoimetrick stepping continuous valve camber whatchamacallits are too confusing.
 
IT's not so bad........................really. It's what happens when people who don't have a clue about gas flow and regulation begin selling stuff online and making claims for it that could cause people to blow themselves up. But yeah it's nice to just do a full manifold switch. Then you know exactly what you have and that it's calibrated properly for the fuel you want to use. I'm lucky in that my friend from the UK is a licensed gas installer (or whatever they call them) he's certified by the UK government. Taught me about manometers and proper flow and regulation, btu content and so on. So now doing a conversion is second nature and I have no issue making it correctly.
But I see these guys on YouTube and other places telling people stupid things. Just makes me SMDH that more folks don't die
 
So I based this entire project on the belief that the manifolds and fuel regulators where the same on the NG and Propane model. It is feeling like that is not the case. Worse case scenario, I end up paying a guy to come out and run me a NG line. End in the hole, but not catastrophic. Stupid tax I guess.


That said, I am not done trying to figure this one out. Thanks for all the coaching here. Genuinely appreciate the time and effort.

LM, I am leaning hard on you, but can you tell me exactly what a fixed valve is? Vs what? Thanks
 
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I believe a fixed valve has just a few possible settings. Like hi, med and low. A variable valve is anything from low to hi.

DJDeeg. Try to find a propane weber grill that is listed for just $20 or even free to pick up and rip the manifold off it. Manifolds are one of the more durable parts of a weber grill, so even if it looks like a wreck, the manifold is probably still good.
 
CJ is it possible they sent you the wrong orifices and at least on the 1000 I had a ng manifold that they stuck a propane regulator on it same thing ran like an inferno. Got a propane manifold from Jon who helped me out. At first when I looked at both orifices they looked the same size but that was not the case.

Do you have a piece of 16 gauge wire lying around if not you could get a foot at home depot for a buck and change. At least on the 1000 a 16 gauge wire will fit in a natural gas orifice it will not fit in a propane orifice only an 18 gauge piece of wire will fit in it. It would seem strange to me that those valves were not continuous as weber could have just changed the orifices using the same manifold when selling a nat gas or propane one less part to inventory but I admit I know nothing about the 670.
 
It is certainly possible that the orifice is not correct, but there is a clear difference between the Weber NG I removed, and the significantly smaller Propane I installed. I will do the wire test tomorrow. Will even swap out regulators with a couple I have lying around, but that is simply a hail mary.

I also struggle with the notion that Weber specs two different control valves vs one valve, and two orifices. I have a call in to the guys who sold me the orifices asking him of he would drill me a test one and a smaller dimension. Just to see what difference it would make. I did a bunch of chicken thighs tonight, and there is no doubt I simply have too much heat. Ill never manage a decent rib cook without standing over then the entire time.

I'm honestly a little bummed. I fear a call to the gas man to run a line out back is next. I will consider that the ultimate failure.
 

 

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