Thursday, July 30, 2009
coleman check valve
I dissassembled a Coleman "suitcase" stove last week to get to a problematic part. Most parts on a coleman are trivial to service. The exception is a small object buried in the fount called a "check valve".
There's not an easy way to get to it, it can take a special $50 tool, and can get very, very stuck. Many people go their whole camping lives without having to change one of these doodads. I got mine out and replaced it today and cranked it up. Runs and holds pressure like a champ.
Here's how it works. Consider what happens when you pump up a Coleman fuel gear:
* release the plunger by rotating it a turn or so CCW.
* pump until you reach desired pressure
* lock the plungber back in place by rotating it CW until you feel it seat.
When the plunger is screwed into place it prevents air from leaking out. But what keeps the air from leaking out after the plunger has been opened? That's the check valve. It contains a ball little opening, blocking outward air movement. The screwed-in plunger and the check valve are the "belt and suspenders" system that keep the explosive fuel/air mix inside the gear where it belongs.
Speaking of which, I just called Atmos to report a possible gas leak around our meter out back. I might be imagining things; it's either faint or not there at all. But they are apparently on the way. I don't think we are in great danger of blowing up. But if you hear sirens tonite and I don't post anymore...
 more correctly, the air stem it's connected to prevents air from leaking out, but you get the idea.
 there's a third safety, in a way. The check valve sits in fuel but has a snorkel like a Hummer, so in case it depressurizes only air comes shooting out the hole in the plunger, not fuel.