The buyers of a stove I sold wanted to know if the burners worked. Initially, the plan was to unhooked my stove, move it out of the way, move the other stove from the outside into the kitchen and temporarily hook it up. Hmm… Naw. Too many big heavy stoves to be moved about.

Second plan; leave the sold stove outside, link together enough gas connector hoses to reach from the kitchen gas line to that stove, a distance of 24′.  I had enough connectors I salvaged from other stoves in my inventory to almost reach. Just one more would be needed. I also needed enough plumbing hardware to link the connectors. The hardware store sales associate had a blast trying to figure out all the MIP, FIP, flare parts needed to link six hoses together!

However, two things didn’t go well with the second plan. First, all those lovely little MIP, FIP and flared parts and the additional hose totaled nearly $100. And the entire 24′ long linked connectors hose leaked gas like a sieve.

Third plan. Leave the stove outside and hook it up to a propane tank. I returned the expensive collection of plumbing parts, bought a hose and regulator assembly and one part to connect the regulator hose to the manifold. I liked this plan the best. My stove could stay put in the kitchen.  All the gas testing could be done outside so if there were any serious leaks, no big deal.

This part needs to connect the assembly to the manifold.

Sweet! It all worked well enough to past the basic test. The four cooktop burners and the griddle burner worked. I only need to see if every cooktop burner burned gas.

What I determined, later, is I had witnessed an NG configured stove trying to burn propane. Seems obvious, doesn’t it? But I didn’t yet understand what needed to be done to the stove to handle propane. The flame profiles seen here are characteristic of a system that isn’t throttled back properly for propane. All the orifices are too large.

Basic info bits about NG & LP

Natural gas is far more abundant in the US, half as energy dense as propane, lighter than air but external forces can easily affect that; temp 3542F.

Propane gas is less abundant, twice as energy dense (hotter), heavier than air but external forces can easily affect that; temp 3623F.

LP gas is more potent than natural gas. One cubic foot of natural gas generates about 1,000 BTUs (British Thermal Units) of heat. Propane generates about 2,500 BTUs per cubic foot! It also tends to be delivered to the stove burners at a higher pressure than NG (0.4 psi for LP vs 0.25 psi for NG). When converting a stove from NG to LP gas, the gas flow has to be throttled back to maintain the same BTUs the stove burners are designed to sustain. If I just piped LP into my NG-configured stove I could turn my stove into a modest flame thrower. Pass.

	psi	BTU per cubic ft	air/gas ratio
Natural gas	0.25	1000	90% / 10%
Liquid propane gas	0.40	2500	96% / 4%

From Inspectapedia

“The gas pressure delivered to a heating appliance (gas range, clothes dryer, gas heating furnace, gas fired water heater, etc) needs to be both constant and at the proper pressure for that appliance.

Because of varying outdoor temperatures, the LP gas pressure inside the storage tank may be as low as 10 psi in freezing weather or as high as 200 psi with the tank exposed to sunlight in hot weather.

And in natural gas fuel systems the gas pressure delivered from the gas main in the street can also vary widely by area, season, time of day and for other reasons.

Regulator(s) have to keep gas flowing to the appliance(s) at that pressure even as pressure in the storage tank changes and even when the number of appliances consuming gas changes (as devices turn on and off in the building).”