GAS SUPPLY
Why your new appliance underperforms on propane
You bought a bigger appliance and it does not deliver what the specification promised. Nine times in ten the appliance is fine and the line feeding it is not.
- Chino Valley, Williamson and Paulden
- Local conditions
- No sales pitch
Answered 24 hours, including nights, weekends and holidays.
Call (928) 766-1925The problem in one paragraph
Gas piping is sized to deliver a specific volume of fuel over a specific distance at an acceptable pressure drop. Every fitting, every foot of length and every reduction in diameter costs pressure. A line that was correctly sized for the appliances originally installed can be entirely inadequate for a replacement that demands more, even though it looks identical and connects the same way.
So the new range boils water slowly, the new heater cannot maintain output, or the tankless unit drops temperature when a second tap opens. The appliance is performing exactly as it should on the fuel it is receiving. It is simply not receiving enough.
This is common on properties here because so many run on propane rather than natural gas, and because appliance capacities have generally risen over time. An installation that was correctly sized for the appliances of twenty years ago is not necessarily adequate for what has replaced them, and nothing about the pipe itself will tell you that.
Symptoms and what they usually point at
Gas supply problems have a recognisable signature, particularly the way they change when more than one appliance runs.
| Symptom | Likely cause | Note |
|---|---|---|
| New appliance underperforms from day one | Line undersized for the new demand | The most common single cause |
| Fine alone, poor when another appliance runs | Total demand exceeds line capacity | Classic sizing signature; test by running them together |
| Yellow or lazy flame on a burner | Combustion or supply issue | Stop and get it looked at; this is not a performance question |
| Water heater output drops when the range is on | Shared undersized run | Very common where a line was extended for a later appliance |
| Worse in cold weather | Regulator, or vaporisation at the tank | Propane vaporisation falls with temperature and tank level |
| Smell of gas at any time | Leak | Leave, then call from outside; this is not a diagnostic exercise |
The second and fourth rows together account for a large share of what people report as a faulty appliance. Running two appliances at once is a genuinely useful home test.
The local wrinkle: cold weather and tank level
Propane behaves differently in January
Propane has to vaporise from liquid before it can be burned, and the rate at which it does that depends on temperature and on how much wetted surface area the tank has, which falls as the tank empties.
January normals in town sit near a 21F low, and it is colder out toward Williamson at around 5,053 feet. On a cold morning a tank that is running low can genuinely struggle to supply peak demand, even where the piping is correctly sized and the appliances are fine.
That is why a problem which appears only in cold weather, or only when the tank is low, is worth distinguishing from a sizing problem. They present similarly and the fixes are entirely different: one is a piping question, the other is a tank sizing and refill scheduling question for your propane supplier.
What proper gas work involves
Not a job to improvise
Gas is the area where the consequences of getting it wrong are not recoverable, and the standards reflect that.
- Sizing calculated from total connected load, developed length and the number of fittings, not estimated from the size of the existing pipe.
- Correct material and approved connectors throughout, with an accessible shutoff at each appliance.
- A sediment trap where required, which is a small detail that is routinely omitted and routinely picked up at inspection.
- Pressure testing of the completed installation before it is put into service, and a leak check at every joint.
- Permitting through the Town of Chino Valley, which has adopted the 2024 International Fuel Gas Code, or through Yavapai County for properties outside the town limits.
- An Arizona ROC licensed contractor. The registrar's licence search is public and takes seconds.
If a quote for gas work does not mention a permit or a pressure test, that is worth asking about before rather than after.
What we do about it
The starting point is the total load. That means listing every gas appliance on the system with its input rating, measuring the actual developed length of the run, and counting the fittings. Those three inputs produce a required pipe size, and comparing it against what is installed answers the question directly.
If the line is undersized, the options are usually upsizing the run, adding a dedicated run for the high-demand appliance, or in some cases adjusting the regulator arrangement. Which of those makes sense depends on the layout, and it is a genuine choice rather than a single prescribed answer. What each involves is on the gas line page.
If the line is correctly sized and the problem persists, the investigation moves to the regulator, the tank and the appliance itself, in that order. That is a different conversation and often one to have with your propane supplier as well as with us.
In practice a load calculation is a short process rather than a project. It is usually done on the same visit, it costs a fraction of what replacing an appliance would, and it produces a documented figure you can keep. That document is worth having even if you decide to do nothing, because it settles the question of whether the appliance or the supply is at fault, and it tells the next contractor what the system can carry. If a repair is needed we can usually schedule it straight away, and any warranty conversation with the appliance manufacturer goes considerably better with a measured supply figure in hand than without one.
Questions about gas supply
Can I just fit a bigger connector at the appliance?
No, and it is a common misunderstanding. The restriction is the whole run from the regulator to the appliance, and enlarging the final few feet does not change what the rest of the line can deliver.
It can also create a false sense that the problem has been addressed, which is worse than knowing it has not.
How do I know if this is the line or the appliance?
The two-appliance test is the most useful home check. If the appliance performs acceptably on its own and poorly when something else is running, the supply is the likely constraint.
If it underperforms identically regardless of what else is on, the appliance or its own regulator becomes more likely.
Do I need a permit to add a gas line for a new appliance?
Gas work is permitted in both the town and the county. The Town of Chino Valley has adopted the 2024 International Fuel Gas Code and runs permitting through Development Services; properties outside the town limits go through Yavapai County.
The permit brings an independent check on the pressure test and the connections, which on gas work is worth having regardless of who did it.
My tankless heater drops temperature when two taps run. Gas problem?
Frequently yes. Tankless units have a high peak input, and they are the appliance most likely to expose a line that was adequate for everything before it.
It is worth checking the gas supply before concluding the unit is undersized or faulty, because the symptom is identical and the fix is not.
Written and reviewed by the Chino Valley Plumbing Pros team. We publish under the company name rather than under an individual byline, because the work behind these pages is done by the crew rather than by one person.
Gas work on this site is carried out to the 2024 International Fuel Gas Code (IFGC) and 2024 International Plumbing Code (IPC), adopted by the Town of Chino Valley, with permitting through Town Development Services inside the town limits and through Yavapai County outside them. Licence status for any Arizona contractor, including us, can be checked on the Arizona Registrar of Contractors public licence search.
New appliance not performing?
Before you return it, let us check what the line can actually deliver.