Converting house generator from propane to nat gas

[Just Joe]

Anyone done this before? I have a few questions.

Don't want to jerry rig something, want to do it properly.

How specific are the parts?

Seeing alot of jerry rigged solutions on YouTube.

Thanks

[Just Joe]

I think I just found the answer:

https://resources.kohler.com/power/kohler/enginesUS/pdf/trifuel_conversion_kits_sellsheet.pdf

[ATtiny85]

Oh yeah, just use a kit and do it. It is very common. From small BBQ up to very large industrial systems.

[Just Joe]

Thanks for the encouragement.

[uniwelder]

I’m curious to ask… how long would your generator run with a 20 lb tank of propane?  Does it make economic sense to convert to natural gas? I’m assuming this gets used once a year for emergency situations.

[bradne]

You probably have a good reason for converting, but keep in mind that natural gas fails occasionally also.  Propane tanks just sit there with little maintenance.  I only mention it because several years ago, the region I am in had a particularly severe cold snap and the gas company ended up diverting a lot of natural gas to more severely impacted areas.  I was not connected to the system but I had several friends that lost their heat.  When they do that, they will not turn on the pipeline until they go to each house and inspect the heater and water heater individually (some safety requirment).  You can imagine the huge lift that causes. 

[Just Joe]

Sorry for the slow response.

Our home was on propane when we bought it. No gas on our street until the year or so after we purchased it (30 year old country house).

We were renting the propane tank ($100/yr) which locked us into one supplier (Suburban Propane) and SB's prices more or less tripled on the last fill ($2 initially up to almost $6 per gallon).

So we decided to switch to gas. Single supplier problem again. Ultimately we plan on having an all electric house but I don't like to discard working appliances so we'll go electric as things wear out. I want the gas connection for the generator though and if we have any ice storms where the temps are down around zero so we can heat with gas using a hybrid heat pump / gas furnace. We had one at our previous house. 

The house had a propane instant water heater that had to be replaced so we went with a HPWH. Love it! Have a propane central furnace (split unit) that was converted to gas yesterday.  When the upstairs (electric resistance heat) broke down, had a new heat pump installed.

I don't have the numbers for you but the payback ought to be just a few years. This was not a cheap project.

$200 for generator conversion fuel regulator (to do)
$1200 for new HPWH plus $400 install (done) AO Smith
$500 to attach house to gas meter and convert furnace from propane to nat gas (done)
??? convert gas logs for emergency heat (to do)
??? new heater for basement TV area (to do), existing heater is propane only, no convert
$1500 to run gas line across large lot. Gas company would do XXX feet, my cost for the rest (done)
$800 if I have to hire someone to remove the existing propane tank b/c SB charges for that. Think I'll had dig it myself.

ALL that and it is still cheaper than the last fill of our propane tank.

Could have bought a new propane tank for ~$1500 and shopped around for the best propane prices each time it needed a fill.

When we first moved here the generator ran often due to frequent power outages. Not as much lately. Will be nice not to worry the propane will run out due to furnace and generator burning fuel during a weather event.

I am considering a bi-fuel or tri-fuel conversion regulator so we could run the generator off of a BBQ propane bottle in a pinch but not sure I'm committed enough that I want to purchase and fill a 100+ gallon propane tank. The black out problem isn't frequent enough.

Most manufacturers publish an estimated fuel consumption chart that would answer your question about how long a given generator would run on a BBQ tank. 

[Just Joe]

Just hopping in here to post that it turned out that our generator is dual fuel from the factory. There is a fuel block (aluminum distribution block).

Remove the fuel block to carb hose, remove barb fitting from the outlet labeled propane and screw it into the NG outlet. Take the threaded allen head plug from the NG outlet and move it to block the propane outlet. 

In other words, swap the threaded plug for the barbed fitting. Use NG rated thread sealant from the hardware store. Reattach the fuel line.

That's it.

I also changed the spark plugs, and inspected the air filter, and did not change the oil b/c it looks brand new. Put it back together.

Found a little case rust that will need to be addressed soon. Sandpaper and paint.

[ATtiny85]

Awesome. Great news. Now and then I wondered how this ended up. Thanks for the follow up.

[iluvzbeach]

We bought a gasoline generator a few years ago and DH added a kit that allows it to also run on natural gas or propane. We have two natural gas hookups outside but DH preferred to have propane be the first fuel source for the generator. We’d had everything for about three years and never used it until almost two weeks ago when we had a 27 hour power outage. DH hooked up the generator and we ran it on one of our propane tanks. We were shocked that we were able to get more than six hours’ usage out of each 5 gallon propane tank! It was impressive and we were one of the only local families who didn’t lose the food in our fridge, kept our house warm & had nice, hot showers.

DH’s insistence on the generator & related accessories really paid off!

[GilesMM]

Natural Gas is preferred generator fuel for minor electricity hiccups.  We live in the PNW.  When "the big one" hits, natural gas could be offline for months so we will be SOL.  Those with propane or diesel will be online longer, but they will run out eventually.  Diesel generators use 1-2 gal/hour.  So with a 500 gal tank you might run it 300 hours.  That's ten hours/day for a month. Better than nothing.  We will be cooking and heating with wood at that point.  A more viable long-term solution would be a solar setup to charge a battery (possibly in an EV car) during the day to provide electrons for the fridge, heat pump, etc.  This would work in a mild climate but probably not with severe heat or cold requiring heating or AC most of the day.

[Just Joe]

A follow up - you can choose when the house generator does its self-test. I finally opened the disconnect panel in the garage and found the owner's manual in there. Wahoo! Set it for Sunday afternoon. I like to hear it run once a week so I can be sure it does run and that it runs well. We're in the country so no neighbors to bother with the noise.

Our goal was to get off of expensive propane to NG. Basically for less than the price of refilling the propane tank, we put in a long gas line, upgraded to a HPWH from a thirsty propane powered instant water heater, converted the house furnace from propane to NG, and other details. The annual cost of NG is miniscule compared to what we were paying for propane from Suburban.

It took Suburban 2.5 months to get around to picking up the old tank after promising next week several times.

GilesMM if we had gas outages here or frequent power outages I'd buy a huge propane tank (new) and pipe it into the generator fuel block allowing me to switch back and forth between fuel sources at will. A ball valve and a toggle switch is all that would be required to swap fuels on our generator.