How to increase gas pressure

DamienRival

I run a coffee roasting company in Philadelphia. The roaster requires 7" WC to operate at capacity. The city of Phila. guarantees 4.5" which is what we have currently. In the cooler months, gas pressure in the city is increased to 6.5" if we're lucky. Needless to say we can't roast to capacity therefore limiting our output.
I'm surprised how difficult its been trying to find a solution or even an HVAC or plumbing company that is familiar with a solution. Ideally we would have the ability to increase by 3.5"WC.
There were two suggestions, a gas booster or a gas regulator. The gas regulator was suggested by a commercial kitchen equipment contact. I was unsure whether that would increase the max input. Any advice would be much appreciated. I did search the forum but did not find a similar discussion.

Thanks

Jamie Hall

If all the supplier can deliver you is 4.5", changing the regulator isn't going to help. A regulator regulates; it can reduce incoming pressure, but not raise it. You need a booster. And a big enough gas line from the street to feed it.

DamienRival

Thanks Jamie.
I figured that was the case. I'm thinking its best to contact a manufacturer and then have them suggest local company to install. Up to now, all the plumbing/heating companies I've spoke to don't work with boosters. Would you be familiar with a manufacturer that may be able to work with me?

ratio

Pay particular attention to the volume of gas you need as well. Pressure is just part of the equation. Around here (adequate local infrastructure implied), it's common for some to try turning up the gas pressure in an attempt to overcome undersized gas lines that won't flow the proper volume.

Tim McElwain

What they can guarantee you is not typical of what you may be getting for pressure on a daily basis. It sounds like you are on a low pressure system less than 1 pound of pressure typically 14" W.C. Those systems usually deliver between 7 to 10" W.C. most of the time. The exception would be in extreme cold weather.

I would actually monitor the gas pressure for a couple of weeks to see what you are actually getting. The truth is a lot of equipment that is out to day needs more than 4.5" W.C.

Check with other manufacturing facilities in the area who may be on a different gas line for higher pressure. Some utilities will do that.

You need to get together with the engineering division of your local utility.

DamienRival

From the gas company.

"Basically, the building has a 4.5” WC pressure (typical for Philadelphia properties) "

We monitor the pressure daily. In the cooler months it gets boosted to 6.5"

We were just quoted on an Eclipse Compact MD101 a light duty unit.

lchmb

set a propane tank

EBEBRATT-Ed

@DamienRival , In many of the large older cities the gas lines in the street are so old they leak....and they leak more when the pressure is raised which is why the utilities run low pressure. If thy raise the pressure they give away a lot of free gas. West Hartford, CT runs at 6" wc for example. You circumstance is not unusual.

Booster cost $$ but it is the only thing that will work. A gas regulator can only reduce pressure not raise it. Eclipse is fine. You might try googeling "Etter Engineering Company". They are in CT and sell boosters. The town escapes me right now.. There are only 3 or 4 companies that make them.

Yes, as @Tim McElwain mentioned you first stop is the utility engineering company

STEVEusaPA

Keep in mind with Peco, when it get's cold, that pressure will drop even more. They will move their interruptable customers over to heating oil to try to relieve the demand on the grid, but in Philly with Peco, you may have problems.
Even if you could just get a bigger regulator, you would need a bigger supply pipe.
You'll get clobbered with propane, especially if there is any issue getting a delivery (small street, can't park or block) or with any snow fall, unless you can get a big enough tank(s) for about 2 weeks of run time.

Leonard

I assume you already took your roaster apart to see that it doesn't have a regulator that is taking that 7" input down to some lower pressure ....... change setting or bypass it.

Alternately I wonder if you can just increase the orfice jet size in the burners. If doesn't burn well with larger jets , might have to ask manufacturer if has a different mixing hourglass venturie.

Zman

Leonard said:

I assume you already took your roaster apart to see that it doesn't have a regulator that is taking that 7" input down to some lower pressure ....... change setting or bypass it.

Alternately I wonder if you can just increase the orfice jet size in the burners. If doesn't burn well with larger jets , might have to ask manufacturer if has a different mixing hourglass venturie.

This is good advise. You should be able to find a contractor that can navigate this for you. I would advise checking the system for any regulators that could be adding resistance, double check the gas line size in the building a track the actual gas pressure at the appliance and at the meter. Just because they say you are getting a pressure, that does not mean you are getting that much all the time and under load.

ScottSecor

We also have some older gas mains here in my part of NJ. Gas pressure often drops to 5" in some areas during peak demand and rarely goes above 6" during the off peak season. We have not installed a pressure booster, but we have ordered many boilers with a special low pressure gas train. This is typically oversized by one or two sizes, for example say a 500,000 BTU boiler has a 1.25" gas train, for low pressure application it would come with 1.5" or sometimes 2",

As others have suggested, you may be able to upgrade your unit to accept the low gas pressure. BTW, around here the utility companies rarely increase the size of the line feeding the building if it is low pressure. I suspect this is because the gas main in the street is already undersized and if you use too much volume all of your neighbors will suffer.

Jamie Hall

ScottSecor said:

...As others have suggested, you may be able to upgrade your unit to accept the low gas pressure. BTW, around here the utility companies rarely increase the size of the line feeding the building if it is low pressure. I suspect this is because the gas main in the street is already undersized and if you use too much volume all of your neighbors will suffer.

This is a very good caution -- were you to install a booster, keep in mind that it works by sucking gas from the line outside -- which will reduce the pressure in that line. If the street main can't maintain the flow -- which is very possible -- you will end up snuffing out burners all up and down the street. This will not make you popular... check with your gas utility.

GBart

Good points, you could end up with some serious liabilities, if you get Gas co engineering approval then it's on them.

CYA

GBart

At any rate this looks interesting.

http://www.etterengineering.com/product/engb-standalone-booster/

EBEBRATT-Ed

@GBart ,
I have done some boosters with Etter. They know their stuff. Not cheap.

As far as alterations to the equipment gas train I thought of that as well but the owner would be taking on some liability there. I would go back to the equipment manufacturer and see if they have a factory solution first.

As @ScottSecor mentioned on larger equipment that is ordered and built for a specific job and application it is common on large commercial equipment to have the factory modify the gas train to save money in some cases and to meet job conditions.

Standardized equipment like cooking equipment, small boilers and water heaters usually are built to a basic spec which is seldom changed

the_donut

Just one question about the gas monitoring, is it before or after meter? Some meters have regulator or orifice built in. This could affect the monitoring.

Leonard

Talking about orfice in meter, for safety gas companies have an orfice in meter sized for your usuage to limit flow in case of pipe break.

If you never notified gas company of your new roaster usage, then the old small orfice in meter could be dropping some pressure at your higher flow rates. Maybe ask gas co to install a higher flow orfice in meter, or at least give you their opinion on options.

As others have said measure pressure at meter and at roaster while it and your other building loads are all burning gas. Your underground and/or building pipe could be too small diameter for the flow your drawing. There are tables for sizing pipe diameter VS length and flow rate, so you don't have excessive pressure drop along the pipe.

GBart

Aye and it's to their advantage because the more flow rate the more you burn and the more you burn the more they make.