Portable generator

[mswlogo]

Originally Posted by Sue Doe-Nym

In post #27, I referred to an opinion by an electrician that a Generac portable is not the best choice. I received a message from a forum member that he is very pleased with his standby Generac unit. I was not comparing the two. We have a Generac, installed in 2016, and have been pleased so far with its performance. The portable is another issue.

The standby Generacs are a completely different beast.

You have to understand how things are today.

China makes a lot of stuff. Some of it is crap, some ok, some excellent.

Besides Honda, China makes 90% of the portable generators. Which are not the best. A company like Generac, has no portable generator, They don’t make them.
So they find one to OEM and slap their reputable label on it.
Might even be a seperate company licensing the name.

That’s what the Westing House is too. Probably another company licensing the name and getting the same product from China.

When you work on stuff you see patterns. You go to buy a part and you find it’s the same part for Generac, DuraMax, Westing House and a dozen more.

Lots of stuff is like this. Lawn mowers, same thing. John Deere lawn mower you see in Home Depot is NOT a John Deere. It’s exactly the same as the Yard Man, husqvarna etc. If it was a John Deere it would cost 3x as much. To compete the buy the OEM one from China and slap their name on it. It’s not a bad unit though. I have one and you start to see patterns when you work on them. Only difference is the color and decals.

So asking which brand portable is kind of a joke. It’s either Honda, China or a Standby.

Regarding propane freezing. Propane freezes at -306F !!! Most Standby generators run on Natural Gas or Propane. The problem is moisture in your tank. Which can also happen to gasoline generators. Keep tanks full. Keep you boat tank full too (not because of freezing but because water in your fuel is bad). Cars don’t have this problem any more. See frost on say a table on your deck? That happens on the inside walls of the tanks. Humid air condenses on the cold walls. When it gets warm it melts and drips into the fuel. Night after night as temps go above and below dew point. This happens inside engines too and water gets in your oil. But it burns off if driven regularly.

https://bepreparedforit.com/do-propa...-cold-weather/

A large stand by system might have a mild heater on the regulator (a narrow point) to prevent fuel freezing and flowing.

You are more likely to have fuel issues with a portable gasoline unit in my opinion.

[DickR]

Originally Posted by mswlogo

...

Regarding propane freezing. Propane freezes at -306F !!! Most Standby generators run on Natural Gas or Propane. The problem is moisture in your tank. Which can also happen to gasoline generators. Keep tanks full....

Presumably that advice about keeping tanks full to avoid condensation inside pertains to gasoline tanks and is not meant for propane tanks. That won't happen with a propane tank. The pressure inside follows the vapor pressure curve for propane, and the top 20% or more of the tank volume is occupied by propane gas, with propane liquid below that. As the tank warms during the day, the liquid propane in the tank absorbs heat from ambient air through the tank wall, and the internal pressure rises. As the tank cools at night or after a cold front passes, condensation will occur inside and pressure drops, although this occurs slowly. But this is propane vapor condensing back to liquid. At some low temperature, well below zero, tank pressure is insufficient to deliver propane vapor to the appliance.

When the appliance uses propane as fuel, the tank pressure drops a bit, some propane boils off to maintain pressure, thus cooling the liquid accordingly, followed by absorption of heat from ambient air through the tank wall.

Since the tank is essentially always at pressure substantially above atmospheric, there is never any introduction of water vapor from the air. If there were any moisture present in the propane, its partial pressure would be way below that needed to cause condensation to liquid water droplets at any realistic temperature. Any water vapor present above the liquid would be flushed out quickly as the appliance uses the fuel.

[mswlogo]

Originally Posted by DickR

Presumably that advice about keeping tanks full to avoid condensation inside pertains to gasoline tanks and is not meant for propane tanks. That won't happen with a propane tank. The pressure inside follows the vapor pressure curve for propane, and the top 20% or more of the tank volume is occupied by propane gas, with propane liquid below that. As the tank warms during the day, the liquid propane in the tank absorbs heat from ambient air through the tank wall, and the internal pressure rises. As the tank cools at night or after a cold front passes, condensation will occur inside and pressure drops, although this occurs slowly. But this is propane vapor condensing back to liquid. At some low temperature, well below zero, tank pressure is insufficient to deliver propane vapor to the appliance.

When the appliance uses propane as fuel, the tank pressure drops a bit, some propane boils off to maintain pressure, thus cooling the liquid accordingly, followed by absorption of heat from ambient air through the tank wall.

Since the tank is essentially always at pressure substantially above atmospheric, there is never any introduction of water vapor from the air. If there were any moisture present in the propane, its partial pressure would be way below that needed to cause condensation to liquid water droplets at any realistic temperature. Any water vapor present above the liquid would be flushed out quickly as the appliance uses the fuel.

Good info. So how do they freeze. I did look it up and it seems it can happen.

[DickR]

Originally Posted by mswlogo

Good info. So how do they freeze. I did look it up and it seems it can happen.

On looking further, it does seem that there is some disinformation out there, or perhaps just poor explanations. First, the propane itself will not freeze until its temperature gets to around -306 F. The actual freezing point will vary a little, because the "propane" delivered isn't pure propane, but has small amounts of lighter gases, including ethane, and heavier gases, such as butane.

That reference (https://bepreparedforit.com/do-propa...-cold-weather/) that refers to propane freezing at -44 F is a good example if misuse of words, in this case "freezing." That -44 F is the approximate temperature of propane fuel at which the pressure it exerts within the tank is one standard atmosphere (14.696 psi). At that pressure, propane from the vapor space above the liquid can't flow out to the generator, since there is no pressure difference to cause flow. Actually, flow will cease a bit before the tank gets that cold, because the gas line and pressure regulator both induce pressure drop.

In certain atmospheric conditions, icing can occur at the carburetor. On my Kohler 14KW standby, I installed their carburetor heater kit to prevent this. It runs off AC power from the house and activates when the temperature goes below 32 F. Other cold weather protection can be installed, such as a battery warmer or crankcase oil heater. I opted for the carburetor heater, figuring that cars left outside overnight in subzero weather usually start readily the next morning. In the 4-5 years I've had the generator, it's never failed to start when needed or for the weekly self-test.

[John Mercier]

Originally Posted by mswlogo

The standby Generacs are a completely different beast.

You have to understand how things are today.

China makes a lot of stuff. Some of it is crap, some ok, some excellent.

Besides Honda, China makes 90% of the portable generators. Which are not the best. A company like Generac, has no portable generator, They don’t make them.
So they find one to OEM and slap their reputable label on it.
Might even be a seperate company licensing the name.

That’s what the Westing House is too. Probably another company licensing the name and getting the same product from China.

When you work on stuff you see patterns. You go to buy a part and you find it’s the same part for Generac, DuraMax, Westing House and a dozen more.

Lots of stuff is like this. Lawn mowers, same thing. John Deere lawn mower you see in Home Depot is NOT a John Deere. It’s exactly the same as the Yard Man, husqvarna etc. If it was a John Deere it would cost 3x as much. To compete the buy the OEM one from China and slap their name on it. It’s not a bad unit though. I have one and you start to see patterns when you work on them. Only difference is the color and decals.

So asking which brand portable is kind of a joke. It’s either Honda, China or a Standby.

Regarding propane freezing. Propane freezes at -306F !!! Most Standby generators run on Natural Gas or Propane. The problem is moisture in your tank. Which can also happen to gasoline generators. Keep tanks full. Keep you boat tank full too (not because of freezing but because water in your fuel is bad). Cars don’t have this problem any more. See frost on say a table on your deck? That happens on the inside walls of the tanks. Humid air condenses on the cold walls. When it gets warm it melts and drips into the fuel. Night after night as temps go above and below dew point. This happens inside engines too and water gets in your oil. But it burns off if driven regularly.

https://bepreparedforit.com/do-propa...-cold-weather/

A large stand by system might have a mild heater on the regulator (a narrow point) to prevent fuel freezing and flowing.

You are more likely to have fuel issues with a portable gasoline unit in my opinion.

Actually the John Deere at Home Depot is a John Deere.
John Deere sets the prices and Home Depot cannot discount them or JD products in any way.
The mowers come in steel crates that cannot be opened by any employee of Home Depot and must be set out for the service technicians from the partnered dealership to come and do the initial multi-point quality inspection and enter the warranty designation before the machine can be purchased.
The ones in the store are the lowest series, and the ones sold online are through the White Glove Ambassador system set up with John Deere.

I used to work for HD and had to set out the crates over night so the when the technicians came in from, they would be ready.

We also use the White Glove Ambassador program for the Ariens and MTD product sold online, I did most of that locally with Belmont Hardware.