Propane pressure question

[airborne_spoon]

My generator runs off 13" WC and the rest of my trailer has a stock regulator pushing out 11" WC.

The generator does not run off the 11" I just tried and it's not doing anything. However, the regulator for the generator only works when the generator is sucking meaning if I don't have it hooked to the generator no gas will come out. Could the fact I'm trying to push gas into it be why it won't work or is there that big of a difference from a 11" to a 13" WC?

Or if I was to get a 13" WC regulator for the trailer would my stove and heater not work anymore?
Generator in question is a Champion 2500 dual fuel.

I can get a "T" adapter for the tank but that is a real PITA because the generator regulator is massive and I dono if it would survive driving down the road if it were permanently connected to my tank.

 

[TonyL]

Do you mean 13"WG?
I'm guessing that US appliances are similar to UK appliances which happily run 30 to 37mbar. To convert WG to mbar, multiply by 2.5

 

[airborne_spoon]

Do you mean 13"WG?
I'm guessing that US appliances are similar to UK appliances which happily run 30 to 37mbar. To convert WG to mbar, multiply by 2.5

No 13" WC water column it's how propane pressure is measured at least I'm the states.

It would make sense y'all Brits would use something different since you measure in lb, stone, mm, mph, km lol pick 1 standard 🤷‍♂️😂

 

[TonyL]

And to my stupidity, I found you write your dates down strangely as well.
WG Is water gauge, same as column.

 

[airborne_spoon]

And to my stupidity, I found you write your dates down strangely as well.
WG Is water gauge, same as column.

So same same but different. I write my dates 20230525 or 25 may 2023 not sure how y'all do it. But we're getting off track.
If it should run fine on 11" then could it be that I'm pushing gas and flooding it then? Also I spoke to the manufacturer and was told 11"to 14" it should run so I'm not sure what my issue is

 

[Jim18655]

I think generators and other gasoline conversions use a demand style regulator that does only pass propane when the engine draws. Works like a SCUBA regulator

 

[Wasillaguy]

That is correct. It may say 13" WC, but they have another one way valve that requires the engine suck it open.

 

[airborne_spoon]

I think generators and other gasoline conversions use a demand style regulator that does only pass propane when the engine draws. Works like a SCUBA regulator

That is correct. It may say 13" WC, but they have another one way valve that requires the engine suck it open.

So am I flooding the engine by pushing gas then?

 

[Wasillaguy]

I would imagine so. I just know on the propane engines I've been around, they use a "negative pressure" final stage, which is a fancy way of saying you gotta suck on it if you want any gas to flow.

 

[CharlesinGA]

What you are holding in your hand is a regulator that cuts the tank pressure down to about 11 inches of water column. The larger diaphragm takes that and then reduces it to about 1 to 2 inchs of water column. Generators that run on LP all have those large regulator diaphragms, known as demand regulators (even my 2500LP Onan mounted under my trailer) either internally or externally.

My travel buddy did a honda 2000i conversion to LP and they told him it would work fine off the trailers external grill/griddle/lantern quick connect if he installed the large diaphragm regulator (demand regulator) inline but close to the generator.

See this Hutch Mountain web page and look closely at the illustrations.

Hutch Mountain even supplies the two regulators like you have, but with a quick disconnect between them. That way, you can run them either off a 20/30 lb LP cylinder or you can separate them and set the smaller regulator aside and connect directly to your RV low pressure (11 inch water column) system, if so equipped.

Charles

 

[IBTripping]

Well. That sucks.

 

[Ray-IN]

Propane gas pressure for appliances is 10.5"-11" water column-when the appliances is running; ie:dynamic pressure, not static.
A factor many do not realize is the size of incoming piping and surface area of liquid LP in the tank both effect that setting of 10.5-11" water column at the appliance regulator when rate of usage increases and outside temperature decreases.
reference: Propane Regulators - LP Gas Pressure Regulation

 

[airborne_spoon]

Propane gas pressure for appliances is 10.5"-11" water column-when the appliances is running; ie:dynamic pressure, not static.
A factor many do not realize is the size of incoming piping and surface area of liquid LP in the tank both effect that setting of 10.5-11" water column at the appliance regulator when rate of usage increases and outside temperature decreases.
reference: Propane Regulators - LP Gas Pressure Regulation

Well… my stock RV regulator spits out 11". I measured it right after the regulator and also at the furthest point, both were 11" so are you saying that it is lower than that when my stove or heater is running?

 

[Ray-IN]

Well… my stock RV regulator spits out 11". I measured it right after the regulator and also at the furthest point, both were 11" so are you saying that it is lower than that when my stove or heater is running?

Yes. Same thing as your water pressure, when you turn on a faucet water flows, reducing pressure until the pump cycles on and maintains that flow pressure. Then you turn off the faucet and water pressure builds until it reaches the set-point of the pump.

Last winter I had a new state-of-the art 2-stage (98% efficient) house furnace installed. The technician set the LP pressure regulator to 11" WC while the furnace was running.

 

[airborne_spoon]

Yes. Same thing as your water pressure, when you turn on a faucet water flows, reducing pressure until the pump cycles on and maintains that flow pressure. Then you turn off the faucet and water pressure builds until it reaches the set-point of the pump.

Last winter I had a new state-of-the art 2-stage (98% efficient) house furnace installed. The technician set the LP pressure regulator to 11" WC while the furnace was running.

So if my regulator is pushing 11" when nothing is in use does that mean it's not functioning properly and I should get a new regulator that pushes like 12"-13" when nothing is in use?

 

[Lou Schneider]

11 inches WC = 0.397 PSI. 13 inches WC = 0.469 PSI. Tank pressure is in the range of 80-180 PSI depending on temperature. Did you disconnect the first stage of the generator's regulator and connect the demand stage directly to the output of the house generator? If not it's no wonder it didn't work on 11" WC.

I'd get the tank pressure Wye shown in the Hutch Mountain propane conversion kits mentioned above and fabricate a mount for the generator regulator. Maybe using a second hose similar to the one going to the house regulator.

Propane Tank Y

Or just get a second propane tank for the generator.

 

[Gary RV_Wizard]

I think you are making this over-complicated, Ray. In an RV water system, pressure falls at full flow because the relatively small pump cannot supply water fast enough to build pressure. An LP tank has beau coup pressure available, well north of 100 psi (2800 WC"!). The regulator is limiting pressure, not creating it, so output pressure remains quite stable. I've only had occasion to measure a few systems at the appliance end, but I've always found 11" WC.

 

[Lou Schneider]

The generator regulator has a single stage first stage regulator like what is used on a BBQ grill where absolute pressure consistency isn't needed, you can control the flame size by turning a knob. The house regulator is two stage, the first stage stabilizes the tank pressure to an intermediate value so the main stage doesn't have to deal with such a wide variation in pressure giving a more consistent output.

In other words, it's extremely unlikely the first stage of the generator's regulator is consistently supplying the engine's demand regulator with anything near the stated 13" WC. Have you tried directly plumbing the input of the demand regulator to the output of the house regulator?

 

[airborne_spoon]

The generator regulator has a single stage first stage regulator like what is used on a BBQ grill where absolute pressure consistency isn't needed, you can control the flame size by turning a knob. The house regulator is two stage, the first stage stabilizes the tank pressure to an intermediate value so the main stage doesn't have to deal with such a wide variation in pressure giving a more consistent output.

In other words, it's extremely unlikely the first stage of the generator's regulator is consistently supplying the engine's demand regulator with anything near the stated 13" WC. Have you tried directly plumbing the input of the demand regulator to the output of the house regulator?

So I got all the hardware and put it together with the check valve inline. It runs a little rough but if I plug the holes on the valve with my fingers it runs better. There are no leaks but those holes on the cover I can feel some air but it's not gas and has no smell.

I got Champion to send me a new regulator assembly because originally I thought it wasn't working right, (different thing entirely it was good just EBKAC). When that gets here I can see how smooth it runs stock because I forgot what it sounded like.

 

[Ray-IN]

I just bought a new 4kw Pulsar dual-fuel genset. I've only ran it on LP and it came with a LP hose without any outside regulator.
The instructions said to connect the hose to a 20# cylinder and the other end to the Pulsar genset LP fitting. I did and it ran great under load and without a load.

So, airborne how does your instructions read?