Natural gas requirements help.

[pmalavolti]

I am getting tired of fooling with propane tanks so I'm finally working on the gas line to hook up a small space heater and boiler for floor heat. I just measured at the inlet of my shop. I got 5 inches of water column. How does that sound.

 

[Jackfre]

On NG that static pressure is fine, however, what is the input of the appliances you are looking to install. How long are the pipe runs, what size are they. If the piping is not sufficient the pressure will drop like a stone. Also, if this system requires alteration, don't simply try to size it to support your current appliances. Oversize a bit to gain some flexibility.

 

[pmalavolti]

the boiler is 5" wc minimum. other appliance are yet o be determined.

 

[pmalavolti]

at the inlet of the shop i have 1.25 inch. nothing is ran yet. the shop is 125' from the meter. the meter is an al-425 w/10psig and 425 SCFH.

 

[mm08822]

5" wc without load is very low. Many loads require 5-7" , very few are down at 3". The 5" you measured will only drop further under load.

You may be able to increase the pressure to 7-8"wc. Still could be too low. You may need to go to a 2psi main regulator and then reduce to 7" wc at the building. You should call gas co and find out what pressure is available at meter regulator.

As Jackfre said, need to know all the loads, pipe sizes and lengths to go further with sizing.

 

[pmalavolti]

5" wc without load is very low. Many loads require 5-7" , very few are down at 3". The 5" you measured will only drop further under load.

You may be able to increase the pressure to 7-8"wc. Still could be too low. You may need to go to a 2psi main regulator and then reduce to 7" wc at the building. You should call gas co and find out what pressure is available at meter regulator.

As Jackfre said, need to know all the loads, pipe sizes and lengths to go further with sizing.

I thought it was low. I don't know what I can do now. Will it bigger meter at my house with a higher PSI help.

 

[mm08822]

I thought it was low. I don't know what I can do now. Will it bigger meter at my house with a higher PSI help.

Meter size is not the issue. The 425 meter will deliver 425 cfh at 7" wc. That is a lot of ng. It is rated to either 5 or 10 psi maximum allowable operating pressure and can exceed the 425 cfh at higher supplied psi's.

The regulator can have the orifice changed if needed for higher throughput but right now your only problem is pressure.

As said in my earlier post, you need to receive a higher delivered pressure. Either that regulator next to the meter can have the pressure output increased or it could be changed out. 1-2 PSI delivered sounds like what you need for that length of pipe.

Call the gas co and find out what psi they can deliver to your location.

 

[mm08822]

So what size are the load(s)?

 

[HoosierBuddy]

Check your pressure with no load on the meter. In other words, none of your gas appliances anywhere downstream of the system burning.

If you are still showing 5" inches you either need the regulator adjusted (call the gas company) or your gauge is wrong.

If you have 7-inches at your meter with a load on it and your pressure has dropped to 5 inches by the time you get to your shop, your line is undersized between the two. My point in testing it with no load is...if there is no load the pressure throughout the system will be the same. You only get a pressure differential when gas is flowing.

Phil

 

[pmalavolti]

the 5" was with no load

 

[pmalavolti]

So what size are the load(s)?

a weil mcclain boiler that has 175000 btu at inlet 5" wc. i want a space heater as well but dont have one picked out.

 

[pmalavolti]

in case it is not obvious, this meter also supplies my house.

 

[mm08822]

in case it is not obvious, this meter also supplies my house.

No it wasn't to me and not worthwhile assuming.

Ok, so now all loads in the house and the piping details from the meter are needed to do a proper sizing/check of the piping and device throughputs.

Can you post a sketch with above requested info?

 

[naturalgas]

1 1/4” pipe run 125’ from outlet of meter will carry 243k BTU load


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[D45]

in case it is not obvious, this meter also supplies my house.

Take a picture of your meter

GJ helped me to ID my 250k meter

I have a 3/4" pipe running about 60-70 feet to my 75K garage heater and it works perfectly

 

[pmalavolti]

out of the meter i have t. one part feeds the shop w/ 1.25" for 125 feet. the other part is 1" that feeds the house.

 

[mm08822]

out of the meter i have t. one part feeds the shop w/ 1.25" for 125 feet. the other part is 1" that feeds the house.

You are set up better than most! Somebody was thinking ahead.
So as ng stated, the dedicated 1-1/4" line off the meter will handle the boiler at 125' with no problem. You easily have another 75CFH capacity out to the garage for a spacer heater.

You just need to get the pressure up at the meter.

Since the garage and house are split at the meter, the house plumbing is not really any concern. No need for that piping info.

However, you still need to verify the total load thru the regulator and meter. Go read all the ng load nameplates and post each of them.

Also need pics of the regulator information. Need to verify what size orifice is in it for its flow capability.

I found the cut sheet for the AL-425 and it should not be an issue.

 

[HoosierBuddy]

the 5" was with no load

Then your gauge is wrong or the gas company needs to adjust their regulator.

In either case, I'd suggest calling the gas company and scheduling a service call. Meet the gas technician and if he says the pressure is fine, have him check it with your gauge too.

The reason I keep harping on the gauge is pressure gauges can fail and give false readings...especially water column gauges, because one time being hooked up to too much pressure and its ruined.

Phil

 

[mrobins297aaa]

at 125' 1 1/4 pipe will be good for about 275K BTU
here is a chart that we use to use to size low pressure NG systems. (Residential)

And a example of how to use the chart, you take the farthest appliance from the meter and the BTU's it requires and use that column on the chart to size everything else.
The chart is good for .5 psig and below so about 13.5" of WC and below.

 

[pmalavolti]

Is there a way to calibrate them

 

[pmalavolti]

I thank everyone trying to help me on this. I thought I planned ahead to cover this.

 

[HoosierBuddy]

Is there a way to calibrate them

If it's a dial gauge and it's wrong you typically throw it away. Digital gauges can be calibrated...although any I've dealt with that were way off were generally toast. The same as a dial gauge, if you overload the transducer by more than about 10% you'll break the thing.

And, just like a dial gauge it'll still give you numbers. They just won't be correct.

If you really want to know how many inches w/c you have, buy a tube type manometer. Dead accurate every time.

Phil

 

[naturalgas]

Call your Gas Co and tell them you have a pressure problem. Whether you do or not they should come out and check there meter fitt for no charge. They will tell you the accurate pressure and if needed correct their end.



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[aslack99]

You have some good advice from some others above. We deliver gas at 5.3 oz for our customers here, which translates to just over 9"W.C. If you have much less than that you will have issues.

 

[pmalavolti]

i think the gauge is jacked. the wife smelled gas in the shop that i did not. fixed 2 small leaks and put the gauge on with no difference at all.

 

[mm08822]

Buy a new gauge or simply clear tubing and a hose barb and make a manometer.
Fill u-shaped hose configuration with some water and read the delta h created with/without gas pressure.

 

[Lost Pup]

Most Nat Gas Companies are required to maintain/update a database of Customer Load/Usage information. Call them and they will update your record and request a pressure check. Hopefully no cost to you.

Service calls for a pressure check at the meter are quite common but any checks beyond the meter (downstream) depend on your local gas company policies. Some will setup and check pressure at device/load locations or that is left to the customer's HVAC seviceman.

Your local gas company might help with the pipe sizing design info in concert with a new load being added to the meter. The computerized system tools are just amazing today, customer info, load data, piping run are just a click away.

Call them and inquire about it.