Natural Gas Flow or Pressure Requirements

[mahenryak]

Hello Everyone:

First, I would like to start out by wishing each of you a very happy New Year! I have been lurking about and searching this forum for a little while now. I have really appreciated some of the insights I have gained, thus far. I have more of an interest than experience but I would like to slowly enter the roasting business/community by developing a small, loyal customer base and eventually, over the course of a few years, maybe be fortunate enough to earn enough to pay all the bills. Until then, I won't be quitting my day job. I am currently in the process of choosing a roaster. Now for my question.

Is there a typical flow/pressure requirement for running a 5K, 10K or 15K roaster? I have a shop building on my residence that I would like to install a roaster in but my home regulator displacement has recently been measured between 7 and 7.5 inches . I was told by one roaster vendor that I might really need somewhere between 8-15 WC. I see the BTU ratings of some of the roasters I have been looking at but I'm not sure how to work with or interpret those numbers.

Thank you very much.

 

[mahenryak]

So, I think I may be on the right track as far as assessing the NG requirements. For example, I notice that the manual for one popular Turkish roaster indicates a NG pressure requirement of 1/2 psi for its 5, 10 and 15K models. I found a conversion tool from psi to water column inches and found that 1/2 psi translates to nearly 14" of water column inches. This means I will likely need to upgrade my NG service to my residence or, of course, simply opt for propane (not as convenient).

 

[peterjschmidt]

I'm no expert in NG pressure, but it would surprise me if you can use NG for cooking or heat, but it wouldn't suffice for roasting.

 

[mahenryak]

I'm no expert in NG pressure, but it would surprise me if you can use NG for cooking or heat, but it wouldn't suffice for roasting.

Thank you for that. I did contact my NG company and it sounds like they are willing to work with me.

 

[Nugget]

i've had 3 roasters, different sizes and 11 inches was what the manufactures wanted while machine was operating. I think 13 from the line.

 

[mahenryak]

i've had 3 roasters, different sizes and 11 inches was what the manufactures wanted while machine was operating. I think 13 from the line.

Thank you very much.

 

[sae]

Diedrichs and Probats work in the 6-7" WC range (meaning you'd need 7-8" at the gas meter). Some USRC go as low as 3"

 

[mahenryak]

Diedrichs and Probats work in the 6-7" WC range (meaning you'd need 7-8" at the gas meter). Some USRC go as low as 3"

Thank you, SAE.

 

[JohnD18]

I have a Diedrich -12, and the manufacrer requires 8-14 WC, however my utility will only guarantee 4. So, unfortunately, I work with 4 as I can't afford the 10K for a booster. Instead of being able to roast 25 lbs, I only roast 15 at a time. Sucks, but I hope to address it one day and get the proper pressure. Also, after speaking with a roaster mechanic, he said there are a lot of places in Brooklyn that actually roast with as low as 2, because the pressure goes down at certain parts of the day. Idk how true this is, but apparently its a problem, at least here in NY.

 

[mahenryak]

I have a Diedrich -12, and the manufacrer requires 8-14 WC, however my utility will only guarantee 4. So, unfortunately, I work with 4 as I can't afford the 10K for a booster. Instead of being able to roast 25 lbs, I only roast 15 at a time. Sucks, but I hope to address it one day and get the proper pressure. Also, after speaking with a roaster mechanic, he said there are a lot of places in Brooklyn that actually roast with as low as 2, because the pressure goes down at certain parts of the day. Idk how true this is, but apparently its a problem, at least here in NY.

This is very interesting. It turns out the roaster I ended up going with (Ozturk 10k) recommends 13 to 15 column inches. I've decided to go with the propane option until I can deliver the NG to my out building at this level. Apparently, it's a pretty easy conversion to NG if I can get the required upgrade some time in the future. Thank you.

 

[Amhas]

Diedrichs and Probats work in the 6-7" WC range (meaning you'd need 7-8" at the gas meter). Some USRC go as low as 3"

My Diedrich was specked for 9 - 12 WC, if I recall correctly. Never seen or heard of a NG unit that required greater than 12 WC but suppose there could be. Usually a WC that high is for propane. Typical WC for NG at a home is around 7 - 8 from what I understand but can be as high as 10 WC with newer buildings. Either way there's a regulator on your gas line you can use to adjust it that (to what ever that regulator max is). Understand though that adjusting this can impact your home gas devices, such as your furnace and hot water heater. You must check all those devices for what they are rated for and DON'T exceed the max for those units unless you have a separate regulator just before that device.
I have heard that newer buildings/homes or larger commercial buildings have higher pressure regulators on the buildings. However, as I noted above this requires that they use regulators at or on each device (most likely) so that they don't exceed the specifications for each device on that line. I checked all my gas devices and the high range I found was no more than 10 WC. My line was set to 6 or 7 as I recall and I adjusted mine to 9 WC.
The other key which isn't mentioned here is not just pressure but flow and demand from other devices on the same line (down stream from the main line). You can have sufficient pressure but flow rate can impact how your unit works as well. They don't talk about this usually but this plays a big roll in what pressure you need. The smaller the line the greater the pressure you will need to meet the system demand. This is all related to how many BTUs are required of the system and how far you are from the main line (depending on pipe size and other system demands). I ran 3/4" line to my system to provide/ensure adequate flow. I had my NG pressure set to 10 and reduced it to 9 WC and I don't think I can tell much if any difference in the system performance.
2WC would mean that most likely there's a much smaller BTU output for the device or you would require a 1" input to the device. Also the pressure at the regulator is the same as it would be at the device. You don't need to increase it unless you are accommodating for flow issues. I put a pressure gauge just before my roaster so I can see what it is when roasting. You can see a small drop in pressure (maybe a half a WC) when another larger device starts (such as my furnace), but it usually comes back up to within a 1/8" WC from where it was after equalizing.