Propane Regulator - Potential Issue at Low Temperatures

[EscapeBoulder]

This might have been discussed in the forum before, but I couldn't find mention of it.

Some background: Our temperature here in the Colorado Rockies went from 88 deg F on Monday to 23 degs F by Tuesday. A dramatic 65 degs F drop in less than 24 hrs.

We've been running the furnace in our Escape 19'er to aid in keeping the water system from freezing during this brief cold spell. (It's predicted to be in the 80's again in two days! Talk about crazy weather!)

This morning, at 23 degs I checked the green/red indicator on the propane regulator and it showed the selected tank as red, empty. "Whoa"... I though, we're using a lot of propane as the tank was recently filled."

So I switched to the other tank, and later today when I took the tank off to get it refilled the tank indicated as empty was more than half filled. Hm...

Anyway, I took the partial filled tank to the folks who sell us propane, and as the gentleman was giving me a partial fill, he indicated that at cold temperatures (23 deg F, I guess), if the appliance requesting/using the propane (the furnace) is requesting more propane than is evaporating from liquid to gas in the tank (which slows at low temperatures), the tank pressure will drop, triggering the regulator indicator.

So... Apparently, if you're using a lot of propane while the tanks are very cold, I guess you can experience a pressure drop which affects the regulator, and quite possibly could affect one or more of your appliances.

Please comment in this thread what you know about this phenomena.

[UncleTim]

Did you see this post by John?

https://www.escapeforum.org/forums/f...tml#post352511

It is post number 16 in the thread.

[rog mich]

We did a New Year's Eve 2019/2020 camp at Mueller State Park, Divide, CO, probably 9000' elevation. It was cold. In the middle of the night we awoke to cold as the furnace had shut down. I went out and switched to the other propane tank and the furnace fired right up. I "assumed" the regulator line had moisture in it and froze, but this may be the real culprit.

[Brian B-P]

Originally Posted by EscapeBoulder

Anyway, I took the partial filled tank to the folks who sell us propane, and as the gentleman was giving me a partial fill, he indicated that at cold temperatures (23 deg F, I guess), if the appliance requesting/using the propane (the furnace) is requesting more propane than is evaporating from liquid to gas in the tank (which slows at low temperatures), the tank pressure will drop, triggering the regulator indicator.

So... Apparently, if you're using a lot of propane while the tanks are very cold, I guess you can experience a pressure drop which affects the regulator, and quite possibly could affect one or more of your appliances.

As long as there is any liquid in the tank, the propane pressure depends only on the temperature of the propane. Using propane means more must vapourize, and that takes heat, so it chills the propane and the pressure drops.

So yes, this can cause the pressure to drop low enough to affect the regulator, or the ability for the system to flow enough propane for the appliances, and it can cause the pressure-controlled auto changeover device to indicate incorrectly.

The other problem with propane regulators at low temperatures and high flow rates is that the dropping of pressure in the regulator also causes chilling, which can cause visible frost formation on the outside of the regulator - that's harmless unless it blocks the atmospheric pressure reference vent or insulates the regulator too much causing the internal parts to get even colder. When the regulator gets cold enough inside oily contaminants in the propane liquify and interfere with regulator operation, and water (also a contaminant in the propane) freezes. These issues can keep the regulator from working properly or even damage it so it won't work again even when thawed out and drained.

[rubicon327]

They make electric propane tank warmers for cold weather but if you have electric power you could just as easily use a small electric heater to keep the trailer warm.
https://www.amazon.com/WarmGuard-WG2.../dp/B06WGX4V91