Elevated Natural Gas Pressure: 7.5" to 11" Water Column - Appliance Issues

[Truman]

I am installing a new swimming pool heater and need to elevate the natural gas pressure at the meter from 7.5" to 11" water column. Will there be any issues with the other appliances with the higher natural gas pressure of 11" W. C.? If there may be a problem, how can I confirm each appliance will work OK with 11" W.C.? My appliances are:

Furnace, Natural gas, Carrier, model # 58UHV1000-20 - 100,000 BTU
Boiler (Radiant Heat), Natural Gas, Prestige Solo 110 - 110,000 BTU
Cooktop, Natural Gas - 40,000 BTU
Grille, Natural Gas - 18,500 BTU
Hot Water Heaters (2) - 68,000 BTU

Thanks in advance for your advice.

[Mr Bill]

Will there be any issues with the other appliances with the higher natural gas pressure of 11" W. C.?

11" W.C. on natural gas! that's more than LP. you need to call the gas co and ask this question, you will probably need to step up the pipe size is what they will probably tell you. Natural Gas Rating: 3.5" to 5.5 W.C. L.P.Gas Rating: 10" W.C.

[stebs]

Are you sure that pressure you need isnt for propane and not nat gas?

11" on a nat gas line is about double the normal pressure. I can see big bangs in your future if you try and run that high of pressure. Best to call a gas tech or gas plumber about that pool heater.

[beenthere]

You need a contractor.

Sounds like you got a LP unit.

[REP]

In my neck of the woods you need the local gas co to increase the house pressue.If your area doesn't require that,I still think its a good idea.
After the supply pressure is increased you should turn on each appliance one by one .
I have seen pictures of homes that blew up.It is in no way shape or form a joke,its complete distruction.

[Truman]

I have contacted the gas company and they will be installing the regulator to increase the 'natural' gas pressure to 11.5" water column from 7.5" W.C. The Gas company told me it was my responsibility to ensure the appliances will work OK with the 11.5" W C.

I have a pool contractor installing the new heater, and he has worked with the Gas Company in the past to elevate the gas pressure for other customers.

I checked the specs on the boiler and it has a limitation of 13" W C. I could not find the W C spec on the other appliances. I would think the W C upper limit for a forced air furnace (IE, Carrier model # 58UHV1000-20) would be typically the same for most furnaces. Also, the same for a cook top, grille, and water heater. If not, I will need to contact the manufacturer of each appliance.

[skippedover]

Many appliances need an additional pressure reducing valve at their gas inlet to keep the pressure under their maximum. A normal rating for a natural gas appliance like a furnace is a minimum pressure of 4.5-in WC and a maximum of 13.6-in WC. That's why everyone raised their eyebrows at the 7.5 - 11.5 in WC. Those are normally LP gas pressures and sometimes the gas valve is different for LP and sometimes the pilot and/or burner orifices must be changed to a smaller diameter when going from natural to LP. I'd be curious to find out what water heater is being used in your application that requires that kind of pressure. Can you supply a make and model no?

[REP]

Many appliances need an additional pressure reducing valve at their gas inlet to keep the pressure under their maximum. A normal rating for a natural gas appliance like a furnace is a minimum pressure of 4.5-in WC and a maximum of 13.6-in WC. That's why everyone raised their eyebrows at the 7.5 - 11.5 in WC. Those are normally LP gas pressures and sometimes the gas valve is different for LP and sometimes the pilot and/or burner orifices must be changed to a smaller diameter when going from natural to LP. I'd be curious to find out what water heater is being used in your application that requires that kind of pressure. Can you supply a make and model no?

Wow I can't believe this is being interpeted so badly.
Has anyone here ever taken a pressure reading of the house pressure at the natural gas meter? you will find it around 8 inches wc.This pressure is the pressure at the enterance each gas valve. In
the gas valve there is a pressure regulator which knocks down the pressure to a working pressure of that appliance.
Some gas valves have a regulator that requires a higher inlet pressure in order to be able to knock it down to the required working pressure for the orfices and burners of that appliance.
Propane is totally differant in tghat the supply from the tank is the working pressure which is why when converting from nat to propane you completely disable the internal nat gas pressure regulator.

[beenthere]

[QUOTE=REP;6898542
Propane is totally differant in tghat the supply from the tank is the working pressure which is why when converting from nat to propane you completely disable the internal nat gas pressure regulator.[/QUOTE]

Your out to lunch on that.

[REP]

In my area there was a regulator at the tank way before it was piped into the the house.
How do you do it where you are?

[flange]

wow. if you have ever worked on an lp system, you would know that leaving the tank there is a pounds to pounds regulator which drops from tank pressure to a low pressure usually in the single psig range, and then from pounds to inches reg at or near the appliance. in commercial heating, many services of natural gas come in the building at high pressure for large appliances, for example, 5 psig. it is then reduced for those appliances that need it.

in this scenario, the homeowner simply needs to have the gas company raise the pressure from the meter, branch off to his pool heater, then drop the pressure to the remainder of the appliances. this can be done with a single reg, or at each appliance. the utility will most likely require the piping to be complete and tested prior to their arriving onsite. by the way, around here, natural gas distribution in the steet can be up to 80 psig right up to the meter. most is more like fifty though. thats why they can use that tiny tubing now without disturbing your lawn. they just pull it through the dirt, connect each end and move on. its also why they now have to support every meter to the wall, the plastic tubing dont hold crap.

[Truman]

The location of the swimming pool heater is about a 100 - 120 ft from the gas meter. The gas pressure at the present heater is very low, about 2" W. C. because of the long run and diameter of the gas pipe, below 1 1/4". This gas pressure will not work efficiently with a 300,000+ BTU pool heater that I need. The pool contractor believes elevating the gas pressure at the meter to 11" WC will provide 4-4.5" WC at the pool heater which is what the heater needs.

The Gas Company measured the pressure in/out of the meter at 7.5" W. C., similar to what Rep said. Rep, if each appliance has a gas valve to lower the gas pressure to its working level, do I need to worry about the pressure being too high for some appliances?

Skippedover, if natural gas furnaces have a minimum pressure of 4.5-in WC and a maximum of 13.6-in WC, I would think elevating my gas pressure to 11" WC at the meter wouldn't be a problem for the gas furnace. The Pool heater is a Raypak, model 336.

[skippedover]

Well now the music hits the drummer! You never stated previously that the problem is an undersized gas pipe! So you've got so much drop you're raising the incoming? Wow!! You'd NEVER get away with that in our state. 300,000 Btu over 120-feet is more like a 2-inch black or plastic pipe. I've done both for pool heaters but out here we have to pull a permit and the size of the pipe is determined by the National Gas Code for the appropriate gas being used, the distance to the appliance (assuming this is a dedicated pipe to that one appliance) and the Btu input to that appliance.

[REP]

john,do you want to put your aol im on

[beenthere]

In my area there was a regulator at the tank way before it was piped into the the house.
How do you do it where you are?

Tank reg knocks it down to 10PSIG, and then a house/secondary reg knocks it down to 11".

[beenthere]

The location of the swimming pool heater is about a 100 - 120 ft from the gas meter. The gas pressure at the present heater is very low, about 2" W. C. because of the long run and diameter of the gas pipe, below 1 1/4". This gas pressure will not work efficiently with a 300,000+ BTU pool heater that I need. The pool contractor believes elevating the gas pressure at the meter to 11" WC will provide 4-4.5" WC at the pool heater which is what the heater needs.

The Gas Company measured the pressure in/out of the meter at 7.5" W. C., similar to what Rep said. Rep, if each appliance has a gas valve to lower the gas pressure to its working level, do I need to worry about the pressure being too high for some appliances?

Skippedover, if natural gas furnaces have a minimum pressure of 4.5-in WC and a maximum of 13.6-in WC, I would think elevating my gas pressure to 11" WC at the meter wouldn't be a problem for the gas furnace. The Pool heater is a Raypak, model 336.

Ah. So your contractor is Guessing how to correct your under sized gas line.

There is a way. But your contractor is going about it the wrong way.

[hearthman]

If this is NG, you need the gas utility to convert it to a 2 psi system. This will have a 2 psi leg run to the pool heater and another leg feeding the house. If you run a 2 psi line into the house near your main loads, you can then install a second stage psi-wci regulator. This will then provide beaucoup gas to the household appliances. If you just have them change the spring in the meter's regulator to a 12.2 wci system for instance, you will then need to adjust each appliance. Those with standing pilots will need to be turned down.

If this is LP, you can make a similar setup. One difference is, any indoor MP regulator will need a separate vent line run to the outside per NFPA 58.

Since you are having low pressure issues already, the higher pressure system would be needed even without the pool heater. Also, you need to check the CFH capacity of your meter. If it is below your load total, it will need to be changed by the utility.

HTH,

[thump_rrr]

The way Hearthman described is the only way to get enough gas pressure to your pool heater while meeting code requirements.

Whoever is advising you to raise the pressure is an idiot since the maximum allowable pressure drop by code is 1"w.c. at 14"w.c.
It is only 0.5"w.c. at 7"w.c.

At 2 psig the maximum allowable pressure drop is 1 psig and a 1/2" line is good for 367,000 btu at 125'

[ga-hvac-tech]

I agree with Hearthman also.

I would get a LICENSED Plumber out there to evaluate this mess. And be SURE the work is permitted. Insurance co's tend to NOT pay when the source of ignition of a fire is bad utility work.

Oh, and while the moderator has not flagged this, IMO this is the kind of DIY that could get someone killed. IMO this thread comes under the 'No DIY' rule.

[Prettyricky]

best advice...call your gas co. and you might have to also have a plumber pressent to figure out who will do what work. generaly gas co. is responsible for meter to the street and a plumber can work on anything in side.