The stove doesn't work. Actually, it doesn't work reliably. You can't fix an unreliable thing without a sensible diagnosis. Why doesn't it work? And diagnostic work is very much a learned art form. Something you learn from others who've been there before you.

It's all fun and games on a boat until you don't have a hot breakfast.
Then it's a hellscape of granola bars and water until you can find a marina with hot coffee.
The struggle is real. When it's 13°C outside, all you can think of are
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Hot coffee.
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And. The stove doesn't work.
Your world narrows to "hot food" and "hot drinks." And the question of "why?" Why can't I have hot food and hot drinks?
CA describes a failed cooker as a deal breaker. We can't live on a boat with an unreliable stove.
This isn't a recent problem. Here's the history:
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Once upon a time (2 years ago) the stove didn't work on a cold day. Okay. This was weird, but, we have someplace to be, so we set sail and the problem did not recur during that particular voyage.
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COVID-19. That is to say, over a year passes with Red Ranger on the hard.
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October 2020, the cooker didn't work, so I replaced the regulator. It was a chilly morning, but it warmed up. We had day jobs and only spent weekends on the boat, so no hot food isn't a problem. We'll go out.
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May 2021, we're living here and the stove doesn't work. It's 13°C (55°F), and we have no working cooker. We're forced to buy my morning coffee the Sandy Pony donut shop.
The donuts are delightful. But, this is not okay.
We can't live like this in the long run. We're going to head south in the fall. It will get cold, and we'll be at anchor in the wilderness. We can't (trivially) ignore a flaky, unreliable propane system.
Symptoms
The symptom is no gas in the cooker.
We have gas in the tank. We weighed them. One has 4#, the other has 17#.
We have pressure in the line. Just under 100 PSI in the tank that's almost empty, almost 120 PSI in the tank that's almost full.
We're pretty sure this only manifests when there's a cold snap.

What parts can we replace?
The regulator. Replaced October 2020.

The solenoid. Replaced May 2021 (yesterday.) I was touching the old one and a wire broke. Before fixing the wire, I jumpered it so I could flip it on and off without having to run down to the galley. It still worked. I replaced it anyway.
I know it works because it gets hot.

The hose from tank to regulator. Replaced . May 2021, too. It's now super-flexible. And it's the older-style hose (without the big green ACME knob.)
What's left? The stove? Does the Force 10 have some kind of emergency shutoff? No. Can all the valves go bad at once? (Please; how likely is that?)
Diagnosis
When in doubt, I search the internet for hints. What I really need is some help diagnosing propane problems. Instead, I find a lot of other things that aren't really diagnosis procedures. I'm guessing that propane diagnostics are the province of propane dealers and installers, not random, amateur sailors.
Propane — mostly the burny explody aspect — is scary. I've payed folks to mess with my propane in the past. Changing the regulator and solenoid was a big step for me. I now have the yellow tape. And I've found that I can take things apart without breaking them.
I need to learn more diagnostic skills.
My search turned up some discussions about propane tanks freezing (They can't. Propane doesn't freeze until -187°C.) Folks will have have regulator problems in cold cold weather. Propane boils at -42°C; if it's that cold, the propane doesn't boil, and won't flow. They make little electric blanket heaters for this. We're not even at 0°C. We don't need a heater.
For very large tanks, moisture in the tank can be cause subtle cold-weather problems. The solution is a bit of alcohol. The treatments are 2 ounces of methyl alcohol per 100 pounds of propane. For a 20 pound tank, the volumes are too small to matter.
There are some discussions about regulators freezing or getting buried in snow and not working properly. The regulator has to be open to the air: it has an opening to sense ambient air pressure that must be kept clear. The regulator is new. It's mounted properly. We don't have snow.
The hose from the tank has a flow-limiting device in it. The hose is new. Also, the device resets when you disconnect it and let it rest a bit. This is something I've done dozens and dozens of times since the cooker stopped working Saturday morning.
I found an interesting document on the Marshal Excelsior Company site. "Why a regulator freezes up and how to prevent it". Not much of this applies to a marine installation. But there's this nugget: "̌Install the regulator and pigtail so that condensate drains back to the cylinder as shown in Figure 4." Figure 4 shows the regulator's inlet above the service valve outlet.
Hm.
While interesting, I didn't — at the time — know what to do with that. I needed to learn more about diagnostics. And perseverance.
Jeri and Denise from S/V Grace
CA did some work for Jeri and Denise. They wanted to buy us dinner. Jeri also gave us a bottle of cognac. We invited them over for a tasting and to swap sea stories.
Jeri, however, brought some tools. And her own flashlight. She had soaked up the propane story and was dying to figure out why propane was not flowing. After a snifter of cognac, we went back and stared at the propane locker.
There it all was: Tank, Regulator, Solenoid, Wires, Hoses, Brass Line.
Jeri's approach is to follow the propane through the system. The burny explody parts requires a spark, so, no smoking when you do this.
Important. You can't simply open the valve on the tank. It's designed to prevent flow unless there's a proper fitting tight against an internal needle valve inside the tank.
You can, however, use your old hose. Screw it onto the tank. Put your hand over the end. Open it a hair. Whoosh! propane. Okay.
We could take each fitting off. Instead, she decided to trust the new parts and jumped to the output from the solenoid. Unscrew the fitting on the output side. Put a hand over the hole.
Open the valve on the tank. Have CA apply power to the solenoid. Whoosh! propane. Close the valve and open it again just to be sure. Propane.
(And yes, I did sing a few bars of my version of J. J. Cale's Cocaine "If you want to cook out, you want to use the grill, Propane.")
The rigid brass pipe doesn't leak. It may have a kink, but that can't be weather related, can it?

There is, between pipe and cooker, a loop of hose.
"Loop."
At the bottom fo the picture is the rigid pipe from the on-deck locker.
At the top, a bit of rubber hose goes to the back of the Force 10 cooker.
It dips down and rises up a few inches.
This lets the gimbaled stove stay level when we're heeled over while sailing.
Jeri would not give up on this. She leaned over the cooker, peering down behind with the flashlight. She reach down and waggled the hose.
Lifted the low spot up. Let it drop.
Turned on a burner. Whoosh!
Propane!
Jeri lit the stove.
The galley is back in operation. The Force 10 cooks like new. While we drank cognac, I lit the stove. After they left, I lit the stove again.
This morning, CA lit the stove and made coffee for me.
Conclusion
Perseverance is key. I did not have a good diagnostic procedure. And I was not willing to blame the little rubber hose behind the stove.
It was condensate. But not in the propane locker.
It was likely some condensed propane in the low spot behind the cooker.
(It may have been moisture. Once the drop of water got spread out through the hose, it would get blown along the line and make the burner sputter a bit, something hardly noticeable.)
Now we know what we need to check when diagnosing "no gas." It's the following, in this order.
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Waggle the hose behind the cooker. There's nothing to replace here, but it can block the flow of propane.
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Weigh the Tank. This is the most likely culprit. Check the TW on the handle. It's around 17# or 18#, but it does vary.
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Test the tank hose for flow by taking it off the regulator, putting a finger over the opening, and then opening the valve.
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Test the regulator by disconnecting it from the solenoid, putting a finger over the opening, and then opening the tank valve.
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Test the solenoid by disconnecting it from the rigid line, applying power, and then opening the tank valve.
We — generally — try to leave the lines propane-free. We do this by turning off the solenoid and burning the last of the propane from the line and then turning the stove burner off.
We learned a lot from Jeri. And now we owe her (and Denise) a batch of freshly-baked scones. After all, the oven works again.