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Discussion Starter · #1 ·
Hello all,
I know this has been a popular topic of late but I hoping to get some advice from you pros out there.
After the winter storm in Feb, 2021 in Texas I bought a portable generator and added a generator inlet box to my house to power it if the power went out again.
I bought a Westinghouse 12.5KW portable generator and a Natural Gas conversion kit for that generator from PNG Technologies.
I tapped the gas line in my garage going to the Water Heater, got everything hooked up and it works GREAT! So if anyone needs help doing this setup, I have all the info and will be happy top to help with info.
Now comes my problem.... I bought the Westinghouse Generator only because I got a really smoking deal on it. Otherwise I was going to buy the Duromax 13KW generator.
Long story short, I was going to do the same setup for my mother and my Aunt. Bough all the same equipment I did for mine except I bough them the Duromax 13KW generator.
I got everything put together, bought the same conversion kit, the exact same hoses, fittings etc. The only difference is the generator and this thing WILL NOT run on the natural gas.

The regulator on the conversion kit requires a min of 6OZ of gas volume and I thought their service may only be supplying 4oz so I purchased an additional 4oz regulator and still nothing.
The generator fires right up on gasoline and I have even tried starting it on gasoline and switching to NG while running and it will run for about 2 minutes and then the engine starves out.
PNG Technologies is no help and the Guy over there Mat is really somewhat of an *******.

I am hoping there is someone on here with some Natural gas engine knowledge that will off me some help. I am really at a loss as to what may be the problem.

Like I said, aside from the issues with this particular generator, I have this process down and even have a parts list. If anyone needs help getting a system like this setup, please reach out.

Thanks in advance for the help!
 

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I am working on natural gas here with a couple generators.

I am willing to bet your issue is the volume of gas getting to the demand regulator at the generator.

There is an equation you can use to find the BTU available at a particular point in a gas pipe circuit. It is a rather complex calculation that requires a lot of measurements between all the pipes, bends, and reducers.

What you need is roughly 10,000BTU per engine HP. So if you have a 15hp engine you need 150,000BTU.

The gas pressure isn't the issue, per se. It is the volume. Pressure is part of it because if you are drawing gas from your demand reg (at the gen) that draw is pulling from the source (the piping ahead of the demand reg). If that draw drops the pressure in the line ahead of the demand reg too far then the demand reg won't work right. In order to get the pressure ahead of the demand reg up you need the volume there.

In order to set yourself up for the best flow you need a large supply as close to the utility feed as you can get. If your main gas piping off the utility feed is, say, 1" then keep 1" piping as far as you can - and try to keep it as short as you can. The larger the line diameter the more BTU at the far end you'll have. Also, you can't up-size the line and get more gas volume. The restriction will the smaller pipe or fitting ahead of the larger one. So, for example, if your feed for the water heater is 1/2" and then you up-size the line T'd off the water heater line to 1" your restriction is the 1/2" - so you won't get any more volume than what you will get at the 1/2" to 1" change.

Just an FYI also - working with gas lines can be a "pandoras box" - both on the safety aspect and insurance. The latter involves permitting and inspected work which would be best left up to a licensed plumber to navigate. If you do it yourself there is a ton of risk and if things aren't certified (inspected and signed off on) insurance may not cover any issues that come back to the gas line work. Even if you do have it inspected and signed off on, if it wasn't done by a licensed plumber your insurance company may still take issue with it. I'm not saying you don't have the ability to do the work - but just cross your T's and dot your I's - especially if it is someone else's property.

The above is what is hanging me up at the moment. I tapped a 3/8" grill outlet (quick connect, so no need to work on the actual plumbing other than connecting to the outlet) and don't have enough gas. In order to get a larger supply I need a T fitting with a valve added to the service entrance - which is 1". Right off the meter is a 90deg elbow - that is what I need changed to a T. We're working through the formal hoops with permitting and a licensed plumber. I don't have much more to offer at this point, other than the plumber wants a utility reg upgrade (bigger regulator from the utility company) and a permit first before quoting the addition of the T/valve.
 

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You can also reduce the spark plug gap by 20% or so when running on natural gas to ensure a stronger spark. Iridium plugs may help. Can you check their generator on your gas supply?
 

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Hello all,
I know this has been a popular topic of late but I hoping to get some advice from you pros out there.
After the winter storm in Feb, 2021 in Texas I bought a portable generator and added a generator inlet box to my house to power it if the power went out again.
I bought a Westinghouse 12.5KW portable generator and a Natural Gas conversion kit for that generator from PNG Technologies.
I tapped the gas line in my garage going to the Water Heater, got everything hooked up and it works GREAT! So if anyone needs help doing this setup, I have all the info and will be happy top to help with info.
Now comes my problem.... I bought the Westinghouse Generator only because I got a really smoking deal on it. Otherwise I was going to buy the Duromax 13KW generator.
Long story short, I was going to do the same setup for my mother and my Aunt. Bough all the same equipment I did for mine except I bough them the Duromax 13KW generator.
I got everything put together, bought the same conversion kit, the exact same hoses, fittings etc. The only difference is the generator and this thing WILL NOT run on the natural gas.

The regulator on the conversion kit requires a min of 6OZ of gas volume and I thought their service may only be supplying 4oz so I purchased an additional 4oz regulator and still nothing.
The generator fires right up on gasoline and I have even tried starting it on gasoline and switching to NG while running and it will run for about 2 minutes and then the engine starves out.
PNG Technologies is no help and the Guy over there Mat is really somewhat of an ***.

I am hoping there is someone on here with some Natural gas engine knowledge that will off me some help. I am really at a loss as to what may be the problem.

Like I said, aside from the issues with this particular generator, I have this process down and even have a parts list. If anyone needs help getting a system like this setup, please reach out.

Thanks in advance for the help!
What is the gas supply situation? Diameter of pipe length of run and distance from the gas meter?

Also did you install an iridium sparkplug or regap the original down to ~ .022
 

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Discussion Starter · #5 ·
What is the gas supply situation? Diameter of pipe length of run and distance from the gas meter?

Also did you install an iridium sparkplug or regap the original down to ~ .022
Hello, So you are the second person to suggest the iridium spark plug and the re-gap so I am definitely going to try that.

As far as the supply situation goes. I tapped the dryer outlet on both situations where I am having problems. It is a 1/2" line that is probably 50+ line feet from the meter. From there I have a 25 ft - 3/4" hose that runs from the dryer valve to the generator.

On the setup at my home (that works perfectly) I tapped the HWH valve in my garage that is probably 20 line feet from the meter (also 1/2") and have it connected with the exact same 25 ft - 3/4" hose to the generator.

I mean those Duromax 13KW units do not even try to turn over on the NG. Next time I go, I am going to take my westinghouse generator over there and see if it will run their supply.

Thank you for the advice.
 

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Discussion Starter · #6 ·
I am working on natural gas here with a couple generators.

I am willing to bet your issue is the volume of gas getting to the demand regulator at the generator.

There is an equation you can use to find the BTU available at a particular point in a gas pipe circuit. It is a rather complex calculation that requires a lot of measurements between all the pipes, bends, and reducers.

What you need is roughly 10,000BTU per engine HP. So if you have a 15hp engine you need 150,000BTU.

The gas pressure isn't the issue, per se. It is the volume. Pressure is part of it because if you are drawing gas from your demand reg (at the gen) that draw is pulling from the source (the piping ahead of the demand reg). If that draw drops the pressure in the line ahead of the demand reg too far then the demand reg won't work right. In order to get the pressure ahead of the demand reg up you need the volume there.

In order to set yourself up for the best flow you need a large supply as close to the utility feed as you can get. If your main gas piping off the utility feed is, say, 1" then keep 1" piping as far as you can - and try to keep it as short as you can. The larger the line diameter the more BTU at the far end you'll have. Also, you can't up-size the line and get more gas volume. The restriction will the smaller pipe or fitting ahead of the larger one. So, for example, if your feed for the water heater is 1/2" and then you up-size the line T'd off the water heater line to 1" your restriction is the 1/2" - so you won't get any more volume than what you will get at the 1/2" to 1" change.

Just an FYI also - working with gas lines can be a "pandoras box" - both on the safety aspect and insurance. The latter involves permitting and inspected work which would be best left up to a licensed plumber to navigate. If you do it yourself there is a ton of risk and if things aren't certified (inspected and signed off on) insurance may not cover any issues that come back to the gas line work. Even if you do have it inspected and signed off on, if it wasn't done by a licensed plumber your insurance company may still take issue with it. I'm not saying you don't have the ability to do the work - but just cross your T's and dot your I's - especially if it is someone else's property.

The above is what is hanging me up at the moment. I tapped a 3/8" grill outlet (quick connect, so no need to work on the actual plumbing other than connecting to the outlet) and don't have enough gas. In order to get a larger supply I need a T fitting with a valve added to the service entrance - which is 1". Right off the meter is a 90deg elbow - that is what I need changed to a T. We're working through the formal hoops with permitting and a licensed plumber. I don't have much more to offer at this point, other than the plumber wants a utility reg upgrade (bigger regulator from the utility company) and a permit first before quoting the addition of the T/valve.

Hello and thanks for the response and advice.

I had figured the volume might be part of the issue. As I stated the conversion kit came with a 6 oz regulator and I ordered a 4 oz regulator thinking that might solve the problem if supply volume was an issue. Do I have the wrong theory here?

They are in Houston, TX and to to upgrade their gas service to a 2lb service, center-point energy (Gas co) charges $300 to do that. Here in Round Rock where I live the gas company will upgrade to 2lb service at no charge. I am trying to stay away from that option because if I go to a 2 lb service them I would have to install step down regulators on all gas appliances to handle to increased service. And I certainly do not want to do all of that and then find out that has not solved my issue. I am really ready to just pull my hair out over this issue. This should be very simple (like it was for my home)
I appreacite any and all help. Thank you!
 

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Discussion Starter · #7 ·
You can also reduce the spark plug gap by 20% or so when running on natural gas to ensure a stronger spark. Iridium plugs may help. Can you check their generator on your gas supply?
What do you mean "Can you check their generator on your gas supply"
 

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75’ on a 1/2” line (the step up to 3/4 does not provide increased volume) is most likely the issue on a unit that large. It is starving for fuel. Go to the USCarb website and see what size supply line their size grid indicates for your engine size.
 

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Hello and thanks for the response and advice.

I had figured the volume might be part of the issue. As I stated the conversion kit came with a 6 oz regulator and I ordered a 4 oz regulator thinking that might solve the problem if supply volume was an issue. Do I have the wrong theory here?

They are in Houston, TX and to to upgrade their gas service to a 2lb service, center-point energy (Gas co) charges $300 to do that. Here in Round Rock where I live the gas company will upgrade to 2lb service at no charge. I am trying to stay away from that option because if I go to a 2 lb service them I would have to install step down regulators on all gas appliances to handle to increased service. And I certainly do not want to do all of that and then find out that has not solved my issue. I am really ready to just pull my hair out over this issue. This should be very simple (like it was for my home)
I appreacite any and all help. Thank you!
As to the pressure the regulators operate at - my understanding is 14-16 inches of water is the output pressure. On my regulators they are stamped with 6-8oz inlet pressure (8 oz max). 8 ounces is 1/2 PSI and 14 inches of water is 1/2 PSI.

I have not had a chance post-holiday etc to investigate the upgrades. However, my understanding is the regulator would be "larger" in the upgrade, and I interpret that to mean it can supply a higher volume of gas - not higher pressure.

A regulator limits the pressure down stream of it. Think of pneumatic tools vs pneumatic paint spraying. An impact wrench may take all the pressure you can get to it. If you have a compressor that runs at 175 psi the impact wrench won't care. However, your paint gun might only run at 40psi. In order to "step down" the pressure from your compressor you need to put a line pressure regulator ahead of the paint gun that limits the pressure to 40psi. There are flow control valves you can get for air lines also - however, they DO NOT regulate pressure. They resist flow.

All your gas appliances are supposed to run at low pressure, I presume in that same ~1/2psi range. They just consume differing volumes of gas (or require differing amounts of BTU's - which to meet the BTU requirement you need a certain gas volume). It wouldn't make sense to me at the moment to boost the "line pressure" - such as in your numbers to go to 2psi from around 1/2psi. That is 4x the pressure.

What you need is more volume - cubic feet/min, cubic inches/min.

What numbers catch my attention here is that, since you are going to loose volume ability the further down the line you are going to get (and the smaller in diameter the lines get), you need a regulator from the utility that will pass the total volume of:
  • Volume consumed by your devices (not just generator - what about the water heater, furnace, and oven/range at the same time?)
  • Volume lost from service regulator to devices

For example - if your total consumption is 200,000BTU but you loose 80,000BTU then you need to upsize the reg to 280,000BTU or higher so that it is capable of pushing 280,000+ BTU.

In my case, if the service regulator pushes 300,000BTU, the generator consumes (23hp x 10kBTU/hp) 230,000BTU, and the gas appliances consume 275,000BTU with 50,000BTU lost that is (230k + 275k + 50k)= 755,000BTU demand off a 300,000BTU reg - can't do it. The reg has to be up-sized to north of 755,000BTU.

If we have to upgrade the pressure then put a step down reg at each appliance/gas feed that isn't going to be a cheap set up. Quite honestly - I would not want step down regulators at all the devices. That additional set of regulators is too much that can go south.

However, if boosting the line pressure and a step-down regulator is needed - if that could be exterior and feed the existing entrance piping then that might be OK. It keeps the extra "hardware" outside the wall = if something leaks its not in the house. Still, though, I don't like that arrangement.

I am hoping the regulator from the gas company can simply be swapped out with one that has a higher BTU rating - if it is even needed.
 

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yea... too long of run...
too small of pipe.
now if you did go to the high pressure on the small pipe that helps...
you are better off doing the 1 inch pipe and then necking that down at the last fitting.

expense... yea... but worth it!

over build the gas supply is the key on NG as well as LP systems.
the demand regulator will deal with any over volume.
but make sure the final pressure for all of your devices is correct!

if you have not bought one yet a pressure and volume meter set is a must when dealing with close setups.
we over kill on the volume (pipe dia) , then make sure the pressure is perfect at the demand regulator.

and remember any fittings are a minus! a 90 deg takes off several feet of volume capacity!
that is why we say stick to the one inch hard lines for the main feed runs.
 

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This is right off uscarbs website. It’s basic and perfect. If the pipe size and distances don’t fall within the bounds of the chart then expect running problems.

Early distribution systems were low pressure in the street and hampered gas volume and are not very common. Typical distribution systems are under greater pressure around 15psi in most cases. It’s then reduced and fed through the meter to home at around 7” water column. These systems give much more leeway in getting adequate volume through the homes pipe work. If the house in question is in a low pressure area adequate pipe sizes are crucial.

Generator
Wattage
Engine
HP
10
20
30
40
50
60
70
80
90
100
125
1850
3.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
.5
2500
5
.5
.5
.5
.5
.5
.5
.5
.75
.75
.75
.75
4000
8
.5
.5
.5
.75
.75
.75
.75
.75
.75
.75
1
5000
10
.5
.75
.75
.75
.75
.75
.75
1
1
1
1
7500
15.5
.75
.75
.75
.75
1
1
1
1
1
1
1.25
8000
16
.75
.75
1
1
1
1
1
1
1
1.25
1.25
10,000
20
.75
.75
1
1
1
1
1.25
1.25
1.25
1.25
1.25
12,000
24
.75
1
1
1
1.25
1.25
1.25
1.25
1.25
1.25
1.25
 

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and always go the next up pipe dia from any of the charts.
and never have to look back!
 

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Discussion Starter · #13 ·
This is all very good and valuable information. Thank you all for taking the time to help me out with this. I have plenty to look into and research. Thank again everyone.
 

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Texas King, have you tested your 12.5kw Westinghouse under your full anticipated load with the HWH you tapped into running? That is also a big unit to be supplied by 1/2“ off of another appliance. Running under load vs idle require very different supply demands. I would expect that unit to require that you supply it with a 1“ T and line directly off your meter.
 

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Discussion Starter · #17 ·
Texas King, have you tested your 12.5kw Westinghouse under your full anticipated load with the HWH you tapped into running? That is also a big unit to be supplied by 1/2“ off of another appliance. Running under load vs idle require very different supply demands. I would expect that unit to require that you supply it with a 1“ T and line directly off your meter.

Yes I have, It struggled a tad when the central AC kicked on but stabilized and ran fine. I have made a couple of test runs simulating a power outage to make sure I did not have issues when the real thing hit. That wesinghouse 12.5KW is an awesome generator. I would highly recommend. It even comes with an external battery tender.
 

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Discussion Starter · #18 ·
Since your setup works correctly, you could try connecting their generator onto your gas line and see if it works. If it works properly on your connection, you know the issue is the gas supply.
Yes, I would like to try that and probably will, its just a six hour round trip from their house to mine.....
 

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Yes, I would like to try that and probably will, its just a six hour round trip from their house to mine.....
I don’t mean to hijack this thread but have a related problem: I just installed a Century NG conversion on my Duromax XP4850EH dual-fuel generator. Supply is 3/4” 4 foot hose direct from the NG meter. My issue is that even with the new low-pressure regulator’s outlet screw all the way open, it will only start and run smoothly with the choke halfway closed on NG. I’ve seen Youtube videos that report the same. While I can live with it like this, I’m curious what might be causing this obvious lack of fuel to the carb?
 

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I don’t mean to hijack this thread but have a related problem: I just installed a Century NG conversion on my Duromax XP4850EH dual-fuel generator. Supply is 3/4” 4 foot hose direct from the NG meter. My issue is that even with the new low-pressure regulator’s outlet screw all the way open, it will only start and run smoothly with the choke halfway closed on NG. I’ve seen Youtube videos that report the same. While I can live with it like this, I’m curious what might be causing this obvious lack of fuel to the carb?
measure the pressure at the demand regulator
it is in wc.
also what filter do you have on the gen set ?
is it paper or foam?
and where is the conversion plate located?
at the air cleaner side of the carb?

make sure to purge the hoses and NG lines....
it takes a while to get it to pure NG.
are you adjusting the load block?
what size of load block do you have?

if the load block is all the way open you need larger flow.
also you need to keep the hose short from the adapter plate to the load block.

you could have a bad demand regulator as well...

on your house side connections did you use full port valves?
 
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