[cjshively]

Has anyone thought about using LP as a backup if the NG stops flowing? I just ordered a Cummins RS36 generator that can run on both LP and NG. It will be setup on the NG coming into my home but I was thinking about putting a LP tank so we could switch over if the NG pumping stations have problems. LP can be stored for a very long time without issues. I think switching the Cummins from LP to NG is as simple as a change on the LCD control panel. Then have a valve to shut off NG and a valve to turn on LP. Would this be feasible?

 

[Old man here]

36KW, you need to have a lot of propane on hand. You need to estimate how long a 500 gal. tank would last if that is what you are thinking. There are others here that would be able to give you that answer.
I'm jealous though!

 

[cjshively]

36KW, you need to have a lot of propane on hand. You need to estimate how long a 500 gal. tank would last if that is what you are thinking. There are others here that would be able to give you that answer.
I'm jealous though!

Thanks, really I only need enough LP to get me through a few days until the NG would be restored. My buddy was down for two day so that is what I am planning for. yes, we will need to do the math to see what size of tank I will need. Assuming during LP we only run the generator at half load.

 

[54fighting]

This is exactly what I'm thinking about. I have a generator that can run off of both fuel types as well. I was thinking of storing a couple or three 120 gallon propane tanks (with a tank cart). I figure that would get me at least four days, which would be great. The issue that I'm investigating is how to easily attach the propane tank in the event natural gas goes down. I just started a separate thread asking about a dual fuel valve or a work around.

 

[54fighting]

I was thinking about installing a tee between the NG shutoff valve and the generator and installing a shutoff off of the tee (into which the propane could be connected). I'd put a valve lock on the shutoff for the propane, and when switching to propane I would install a valve lock on the NG shutoff. It seems like there would be a valve to accomplish all of this, but if not I'm waiting for someone to tell me why my setup wouldn't work.

 

[ToolLover]

I hope you have a frequency meter to set the RPM and the 60 Hertz when you change from NG to propane.

 

[54fighting]

I hope you have a frequency meter to set the RPM and the 60 Hertz when you change from NG to propane.

I'm not sure what this means, but I would like to. If I had to guess (without knowing why), I'd guess that the generator should run at 50 Hertz when using natural gas and 60 Hertz when using propane.

My generator comes from the factory set to run on natural gas but it can also run on propane. Inside the generator is a knob that is pushed and rotated when converting to propane. Presumably, the initial setup would need to be rerun on the generator control pad to change the fuel selection from natural gas to propane. I'd assume that you go through this process (turning and pushing the knob and changing the fuel selection) to select the correct RPM.

 

[Old man here]

I'm not sure what this means, but I would like to. If I had to guess (without knowing why), I'd guess that the generator should run at 50 Hertz when using natural gas and 60 Hertz when using propane.

My generator comes from the factory set to run on natural gas but it can also run on propane. Inside the generator is a knob that is pushed and rotated when converting to propane. Presumably, the initial setup would need to be rerun on the generator control pad to change the fuel selection from natural gas to propane. I'd assume that you go through this process (turning and pushing the knob and changing the fuel selection) to select the correct RPM.

60 Hertz on any fuel in the US. Your engine has to run at exactly 3600 RPM to generate 60 HZ on a 2 pole generator.

 

[54fighting]

60 Hertz on any fuel in the US. Your engine has to run at exactly 3600 RPM to generate 60 HZ on a 2 pole generator.

Ok, but I don't understand the issue. The generator is built to run on natural gas or propane. There is a process to switch over to propane; i.e., the manual control knob inside the generator and the control panel to select the fuel type. Why would I need something (a frequency meter) in addition to what is provided by the generator?

 

[ToolLover]

Maybe the knob adjusts the fuel flow. Not sure about that.
In my Generac there is a selector to switch from NG to Propane.
Get a cheap VOM with frequency meter built in and set the fuel supply for 60 Hertz. As noted 3600 rpm.

 

[captchas]

you will need a separate gas regulator for each fuel which means separate piping also . there should be more detailed information in your owners manual

 

[54fighting]

So, if I could get back to the original question. We know the generator is designed to run on natural gas and propane, and the switch over on the generator itself is pretty simple.

I don't know where the OP is situated, but I'm in California. If we have an earthquake that knocks out electric we're probably going to lose our natural gas. It would be important to have a propane back up. But I don't want to be changing out all of the piping under those circumstances.

My plan was this. The natural gas line into the generator would have a shutoff. Between that shutoff and the generator I would install a tee. Off the base of this tee, I would install another shutoff valve.

I can't keep a 250 gallon propane tank on my property. I could store a couple 120 gallon propane tanks. If there were an earthquake, I would use a tank dolly to move a tank over to the generator and secure it to an existing post. The tank would have a regulator. I would have a preconfigured pipe with couplings at either end (it would be better if I could use some flexible pipe). One coupling would attach to the propane tank and the other would attach to the shutoff valve that was installed at the base of the tee. I would close the natural gas valve and install a lock on that valve. During those times when the generator was operating off natural gas the valve at the base of the tee would be closed and would have a lock installed (or I'd install a short length of pipe with a cap off the valve).

It seems like this should work. What am I missing?

 

[captchas]

the issue is the line pressure of ng is higher than propane you would still need to swap out the regulator and piping, it's not as simple as of simply flipping a switch on the carburetor

seems you would be better just setting it up as propane and having a pair of 100 gallon tanks

generac is good with making available the owners and installation manuals on their web site or you could ask for more detail in this also wonderful generac forum where i got my own help Ziller Forum

 

[54fighting]

the issue is the line pressure of ng is higher than propane you would still need to swap out the regulator and piping, it's not as simple as of simply flipping a switch on the carburetor

seems you would be better just setting it up as propane and having a pair of 100 gallon tanks

generac is good with making available the owners and installation manuals on their web site or you could ask for more detail in this also wonderful generac forum where i got my own help Ziller Forum

I'll try Ziller.

I'm not sure why the pressure differential would matter. I'd use the same piping (black pipe or galvanized) for natural gas or the propane tank. The propane tank would have a regulator. Why would I have to swap out the piping? I'd only be using a small piece of the existing natural gas piping.

Presumably, if I had a coupling at the generator for the natural gas line I could detach the coupling and with a bit of flex on the natural gas line pull back that line and connect a line from the propane tank to the coupling. If so, I don't understand why I couldn't accomplish the same by simply connecting the tank to the shutoff valve that I proposed.

 

[captchas]

you don't use galvanized pipe on any gas, black pipe only, the gases can break away the galvanization in flakes that make thier way into the system

it would be best for you to have a talk with both gas suppliers and your local building inspector , since permits are needed to make the installation . all should be able to more clearly tell you why one or the other

 

[Browse Deweb]

The RS36 runs at 1800 RPM and 60 Hz. What a fine generator. Congratulations!

Regarding NG vs Propane - What I would do is leave the NG connection and do nothing with the propane. Why? The probability that you would lose NG supply is very low. Installing and filling a propane tank and doing all of the connections and configurations could get very expensive. Perhaps a cheaper alternative would be to have an inexpensive portable genset connected to a dedicated breaker via an interlock, running on gasoline as your backup. This won't run the whole house, but should get you through any major issues like frozen pipes and lost food for the few days you might be out of NG.

 

[Stevo]

Has anyone thought about using LP as a backup if the NG stops flowing? I just ordered a Cummins RS36 generator that can run on both LP and NG. It will be setup on the NG coming into my home but I was thinking about putting a LP tank so we could switch over if the NG pumping stations have problems. LP can be stored for a very long time without issues. I think switching the Cummins from LP to NG is as simple as a change on the LCD control panel. Then have a valve to shut off NG and a valve to turn on LP. Would this be feasible?

I just ordered a Westinghouse WGEN9500 (12500 peak watts) and it is gasoline. I then turned around and ordered an LP and Natural Gas conversion kit. I plan on using Natural Gas as my primary and LP or Gasoline as my back up. The Westinghouse has a Freq meter on it, so hopefully I can adjust it as needed. I also ordered all of the electrical parts to make it so I can plug it into my house system. Two of my neighbors are set up like that.

 

[PatD]

60 Hertz on any fuel in the US. Your engine has to run at exactly 3600 RPM to generate 60 HZ on a 2 pole generator.

Cummins 36KW runs at 1800 RPM and is water cooled.

 

[Old man here]

Cummins 36KW runs at 1800 RPM and is water cooled.

That is a 4-pole rotor.